The function of a buffer is to maintain the pH of a solution. The correct answer is maintain the pH of a solution.
Buffers are important in many chemical processes and biological systems, as they help maintain a stable pH environment, allowing for the proper functioning of chemical reactions and enzymes.
A buffer is a solution that resists changes in pH when small amounts of acid or base are added. It does this by absorbing or releasing H+ ions as necessary. The buffering capacity of a solution is determined by the concentrations of the weak acid and its conjugate base, which together form a buffer system.
Buffers are important in many biological processes because they help to maintain the pH of body fluids and prevent them from becoming too acidic or basic. They are also used in many laboratory experiments and industrial processes where pH control is important.
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wine goes bad soon after opening because the ethanol in it reacts with oxygen gas from the air to form water and acetic acid , the main ingredient of vinegar. what mass of water is produced by the reaction of of ethanol?
The mass of water produced by the reaction of 1 mole of ethanol is 0.0764 g.
The chemical equation for the reaction of ethanol (C₂H₅OH) with oxygen gas (O₂) to form water (H₂O) and acetic acid (CH₃COOH) is;
C₂H₅OH + 3O₂ → 2H₂O + 2CH₃COOH
From the equation, we see that for every mole of ethanol that reacts, 2 moles of water are produced. Therefore, we can calculate the number of moles of ethanol involved in the reaction by dividing the mass of ethanol by its molar mass (46.07 g/mol).
moles of ethanol =mass of ethanol/molar mass of ethanol
moles of ethanol = (Assuming a typical wine with 13% ethanol and 750 mL volume)
0.13 x 750 mL / 1000 mL/L x 1 kg/1000 g = 0.0975 kg / 46.07 g/mol
moles of ethanol = 0.00212 mol
Using stoichiometry, we can then determine the number of moles of water produced by the reaction;
moles of water = 2 x moles of ethanol
moles of water = 2 x 0.00212 mol
moles of water = 0.00424 mol
Finally, we can calculate the mass of water produced by multiplying the number of moles of water by its molar mass (18.02 g/mol).
mass of water=moles of water x molar mass of water
mass of water = 0.00424 mol x 18.02 g/mol
mass of water = 0.0764 g
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5
1 point
What volume of concentrated 18M solution is required to prepare 550 mL of a 2.0M solution?
Type your answer...
1 point
What volume of concentrated 1.5M is required to prepare 25 mL of a 7.0M solution?
Answer in liters
1-61.11 ml of the 18 M solution is required to prepare 550 ml of a 2.0 M solution.
2-0.117 liters or 117 ml of the 1.5 M solution is required to prepare 25 ml of a 7.0 M solution.
To calculate the volume of concentrated 18 M solution required to prepare 550 ml of a 2.0 M solution, we can use the formula:
M1V1 = M2V2
where:
M1 = 18 M (concentration of concentrated solution)
V1 = volume of concentrated solution to be added (unknown)
M2 = 2.0 M (final concentration required)
V2 = 550 ml (final volume required)
Rearranging the formula to solve for V1:
V1 = (M2 x V2) / M1
Substituting the values given:
V1 = (2.0 M x 550 ml) / 18 M
V1 = 61.11 ml
To calculate the volume of concentrated 1.5 M solution required to prepare 25 ml of a 7.0 M solution, we can again use the formula:
M1V1 = M2V2
where:
M1 = 1.5 M (concentration of concentrated solution)
V1 = volume of concentrated solution to be added (unknown)
M2 = 7.0 M (final concentration required)
V2 = 25 ml (final volume required)
Converting the final volume required to liters:
V2 = 25 ml = 0.025 L
Rearranging the formula to solve for V1:
V1 = (M2 x V2) / M1
Substituting the values given:
V1 = (7.0 M x 0.025 L) / 1.5 M
V1 = 0.117 L
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what is the answer to the question?
To determine the number of moles of reactants required to produce 6.2 moles of phosphoric acid (H₃PO₄), we need to use stoichiometry.
How many moles of reactant were required to form phosphoric acid?From the balanced equation, we can see that 1 mole of P₄O₁₀ reacts with 6 moles of H₂O to produce 4 moles of H₃PO₄. This means that the ratio of P₄O₁₀ to H₃PO₄ is 1:4, and the ratio of H₂O to H₃PO₄ is 6:4, or 3:2.
To find the number of moles of P₄O₁₀ required, we can set up a proportion:
1 mole P₄O₁₀ / 4 moles H₃PO₄ = x moles P₄O₁₀ / 6.2 moles H₃PO₄
Solving for x, we get:
x = (1 mole P₄O₁₀ / 4 moles H₃PO₄ ) x (6.2 moles H₃PO₄ ) = 1.55 moles P₄O₁₀
Therefore, 1.55 moles of P₄O₁₀ were required to produce 6.2 moles of H₃PO₄.
To find the number of moles of H₂O required, we can set up a similar proportion:
6 moles H₂O/ 4 moles H₃PO₄ = x moles H₂O/ 6.2 moles H₃PO₄
Solving for x, we get:
x = (6 moles H₂O/ 4 moles H₃PO₄ ) x (6.2 moles H₃PO₄ ) = 9.3 moles H₂O
Therefore, 9.3 moles of H₂O were required to produce 6.2 moles of H₃PO₄ (phosphoric acid).
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1 point
How many liters of a solution would be needed in a solution with a molarity of 10.5 and a 3.6 moles?
Type your answer...
the volume of the solution needed is 0.343 liters (or approximately 343 mL) liters of a solution would be needed in a solution with a molarity of 10.5 and a 3.6 moles.
To determine the volume of the solution, we can use the formula:
moles = molarity x volume
Rearranging the formula, we get:
volume = moles / molarity
Substituting the given values, we get:
volume = 3.6 moles / 10.5 M
volume = 0.343 L
Volume is the quantity of three-dimensional space occupied by a liquid, solid, or gas. It is measured in units such as liters, milliliters, cubic meters, or cubic centimeters, depending on the object or substance being measured.
In chemistry, volume is an important parameter for measuring the amount of a substance in a solution, and it is often used in calculations involving concentration, stoichiometry, and gas laws.
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some toxic substances degrade once released into the environment. what controls the rate of degradation? group of answer choices all of the above moisture chemistry of the substance temperature sun exposure
The rate of degradation of toxic substances in the environment is controlled by several factors. These include the chemistry of the substance, moisture, temperature, and sun exposure. The correct answer is "all of the above".
When toxic substances are released into the environment, the rate of degradation is controlled by all of the above factors. Toxic substances are substances that cause harm to living organisms when they come into contact with them.
The moisture content of the environment where the toxic substance is released affects the rate of degradation. When the environment is moist, the toxic substance degrades more quickly than when the environment is dry.
The substance's chemistry influences the rate of degradation, as some substances break down more quickly than others when exposed to the environment's natural processes.
Temperature also influences the rate of degradation of toxic substances. When temperatures are high, the substance degrades more quickly than when temperatures are low.
Sun exposure also impacts the rate of degradation, with more sun exposure leading to faster degradation than less sun exposure.
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what effect, if any, do you expect the three different substituents on the aromatic ring (para-chloro, para-methoxy, para-methyl) to have on the reaction? explain g
The para-methyl group is not expected to strongly influence the electronic properties of the ring but may affect its steric accessibility to reacting species.
the substituents on an aromatic ring can have a tremendous influence on the reactivity and selectivity of reactions that involve the ring in the case of the three unique substituents you noted para-chloro para-methoxy para-methyl they will probable have exceptional penalties on the response primarily based on their digital and steric properties para-chloro chlorine is an electron-withdrawing group which ability it will pull electrons away from the ring making it a whole lot much less electron-rich and extra inclined to electrophilic assault this can make the ring extra reactive closer to electrophilic fragrant substitution EAS reactions which comprise the addition of an electrophile to the ring the presence of a chlorine substituent can additionally have an impact on the regioselectivity of the reaction favoring substitution at the para role para-methoxy methoxy -och₃ is an electron-donating team which ability it will donate electrons to the ring making it greater electron-rich and much less susceptible to electrophilic assault this can make the ring plenty much less reactive in the direction of EAS reactions on the other hand the methoxy group can moreover increase the nucleophilicity of the ring making it more inclined to nucleophilic aromatic substitution NAS reactions the presence of a methoxy substituent can additionally have an effect on the regioselectivity of the reaction favoring substitution at the ortho and para positions para-methyl methyl -ch₃ is a as a substitute inert substituent that ability it does not strongly have an effect on the electron density of the ring or its reactivity toward EAS or NAS reactions however the presence of a methyl crew can affect the steric properties of the ring making it higher or a whole lot less on hand to the reacting species relying on the special reaction stipulations
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describe the three phases of gastric function and how the gastric activity is activated and inhibited.
The three phases of gastric function are the cephalic phase, gastric phase, and intestinal phase.
The cephalic phase is initiated by the sight, smell, taste, or even thought of food, which activates the vagus nerve, leading to the secretion of gastric juices and enzymes.
The gastric phase is initiated by the presence of food in the stomach. The distension of the stomach walls triggers the release of gastrin, which stimulates the secretion of gastric juices and enzymes.
The intestinal phase is initiated by the presence of chyme (partially digested food) in the small intestine. The duodenum releases hormones that inhibit gastric secretions and motility and stimulate the release of digestive enzymes from the pancreas.
Gastric activity is also regulated by several factors that can activate or inhibit its function. For example, stress, smoking, and caffeine can stimulate gastric activity, while alcohol and some medications can inhibit it. Additionally, the presence of fatty or acidic foods can either stimulate or inhibit gastric function.
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when 0.075 g of koh is dissolved in 1.00 l of 1.0 x 10-3 m cu(no3)2, a precipitate of cu(oh)2 is formed. true or false? (ksp of cu(oh)2 is 2.2 x 10-20)
It is true that when 7.5 x 10-4 g of KOH is dissolved in 1.00 L of 1.0 x 10-8 M Cu(NO3)2, a precipitate of Cu(OH)2 is formed. This is determined through the concept of Balanced chemical reaction.
The balanced chemical reaction can be written as,
2KOH(aq.) + [tex]Cu(NO_{3} )_{2}[/tex](aq.) ==> [tex]Cu(OH){2}[/tex](s) + [tex]2KNO_{3}[/tex](aq.)
moles KOH present can be calculated as,
= 7.5x10-4 g x 1 mole/56.1 g
= 1.33x10-5 moles KOH
= 1.3x10-5 M OH-
moles[tex]Cu(NO_{3} )_{2}[/tex] present can be calculated as,
= 1.0x10-8 mole/L x 1 L
= 1.0x10-8 moles Cu(NO3)2
= 1x10-8 M Cu2+
[tex]Cu(OH){2}[/tex] (s) ==> Cu2+(aq.) + 2OH-(aq.)
Q = [Cu2+][OH-]2
Q = (1x10-8)(1.3x10-5)2
Q = 1.3x10-18
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The correct question is,
When 7.5 x 10-4 g of KOH is dissolved in 1.00 L of 1.0 x 10-8 M Cu(NO3)2, a precipitate of Cu(OH)2 is formed. True or False? (Ksp of Cu(OH)2 is 2.2 x 10-20).
In a titration, 25mL of 0.20M NaOH neutralize 5mL of HCI, what is the acid molarity?
The molarity of the HCl sample is 1.0 M.
In a titration, the moles of acid are equal to the moles of base at the equivalence point.
We can use this principle to calculate the molarity of the acid (HCl) from the volume and concentration of the base (NaOH) used in the titration.
First, we need to calculate the number of moles of NaOH used in the titration:
moles of NaOH = M x V = 0.20 M x 0.025 L = 0.005 mol
Since NaOH and HCl react in a 1:1 molar ratio, the number of moles of HCl present in the sample is also 0.005 mol.
Now we can calculate the molarity of HCl using the number of moles and the volume of the HCl sample used in the titration:
molarity of HCl = moles of HCl / volume of HCl sample
molarity of HCl = 0.005 mol / 0.005 L
molarity of HCl = 1.0 M
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various aspects of this experiment are time sensitive. preparing your samples and taking measurements too soon may yield inaccurate results because the reaction may not have reached equilibrium yet, and so on. to avoid that situation, a student prepares and mixes their solutions to start the reaction. they then make special arrangements to leave their solutions out on the lab bench all day and return that evening (6 hours later) to take their readings. considering the specific species present in the reaction, what, if anything, will the student notice about the absorbance results?
The student may observe a decrease in the absorbance results due to the reaction having reached equilibrium and the concentrations of the species involved having changed over time.
The specific species present in the reaction will determine the rate at which the reaction reaches equilibrium. If the reaction is slow to reach equilibrium, leaving the solutions out on the lab bench for only 6 hours may not be enough time for the reaction to fully proceed and reach equilibrium. This can result in inaccurate absorbance results due to incomplete reaction.
Conversely, if the reaction reaches equilibrium quickly, leaving the solutions out for 6 hours may not have a significant effect on the absorbance results. Therefore, it is important to consider the reaction kinetics and equilibrium characteristics of the specific species present in the reaction to ensure accurate absorbance readings.
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--The complete question is, A student has prepared and mixed their solutions for an experiment, and left them on the lab bench for 6 hours before taking absorbance readings. What considerations should be made with regards to the specific species present in the reaction and how might this impact the accuracy of the absorbance results?--
a solution is prepared by adding 0.020 moles of na 2 hpo 4 and 0.010 moles of nah 2 po 4 to 100.0 ml of water. what is the ph of this solution? for h3 po 4 : ka1
The pH of the solution prepared by adding 0.020 moles of Na₂HPO₄ and 0.010 moles of NaH₂PO₄ to 100.0 ml of water is found to be 7.51.
A solution is prepared by adding 0.020 moles of Na₂HPO₄ and 0.010 moles of NaH₂PO₄ to 100.0 ml of water.
The total H⁺ concentration of the solution will be given as,
H⁺= √(Ka₁C₁)+(Ka₂C₂)
C₁ and C₂ are the concentration of the two acids. The Ka₁ and Ka₂ are the standard values of the solution. Putting all the values in the above mentioned formula we will get the pH of the solution to be 7.51.
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If the He in Problem 3 takes 20 sec to effuse, how long will NH3 take?
Brass is an alloy of copper and zinc. The composition of a 1.00-g sample of brass is analyzed by reaction with excess 1.50 M HCl. The hydrogen gas produced is collected by water displacement. It is found to have a volume of 135 mL at 25 degrees Celsius and 772 torr. The vapor pressure of water at 25 degrees Celsius is 23.8 torr. Assume that only the zinc reacts. Determine the mass of zinc present in the brass sample.
The brass sample has 0.357 g of zinc.
What is mass?The amount of inertia a body possesses and the resistance it provides to a change in its speed or position when a force is applied are measured by a body's mass, which is a fundamental attribute of matter. It is frequently used as a gauge for how much matter makes up a body and gives it weight in a gravitational field.
The chemical formula for the interaction of zinc with hydrochloric acid is as follows:
Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(g)
One mole of zinc interacts with two moles of hydrochloric acid to create one mole of hydrogen gas, as shown by the balancing chemical equation. As a result, the amount of zinc in the brass sample and the amount of hydrogen gas produced by the reaction are equal.
The ideal gas law can be used to determine how many moles of hydrogen gas were generated:
PV = nRT
where n is the number of moles, R is the gas constant, T is the temperature in Kelvin, and P is the total pressure of the gas.
Initially, we must adjust the hydrogen gas volume for the water vapor pressure. The gas's overall pressure is:
Total P = [tex]\rm P_ {H_2 }+ P_{H_2O}[/tex]
where [tex]\rm P_ {H_2 } \ \texte{and }\ P_{H_2O}[/tex] are the partial pressures of hydrogen gas and water vapor, respectively.
P _H2O = 23.8 torr, as we know,
[tex]\rm P _{H_2[/tex] = [tex]\rm P_ {total[/tex] - [tex]\rm P _{H2O[/tex] = 772 torr – 23.8 torr= 748.2 torr.
Converting the volume to liters (L) and the pressure to atmospheres (atm):
P = 760 torr/atm / 748.2 torr = 0.984 atm
V=135 mL / 1000 mL/L = 0.135 L
The temperature must also be converted to Kelvin:
T = 25°C + 273.15 = 298.15 K
These values are substituted into the ideal gas law to find n.
n = PV/RT = (0.984 atm) × (0.135 L) / (0.08206 L·atm/mol·K) × (298.15 K) = 0.00547 mol H2.
When one mole of zinc interacts to create one mole of hydrogen gas, the brass sample also contains 0.00547 mol of zinc.
The molar mass of zinc (65.38 g/mol) can be used to calculate the mass of zinc in the brass sample.
mass of zinc = number of moles of zinc × molar mass of zinc
= 0.00547 mol × 65.38 g/mol
= 0.357 g
As a result, the brass sample has 0.357 g of zinc.
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what is the final volume of 5.31L of an ideal gas when heated from 200 K to 300 K at constant pressure?
The final volume of the gas is approximately 7.97 L. This type of process is often represented on a pressure-volume (PV) diagram as a horizontal line, where the pressure is constant and the volume changes.
What is Constant Pressure?
Constant pressure refers to a thermodynamic process where the pressure of the system remains constant throughout the process. This means that if a gas is undergoing a constant pressure process, its pressure will remain the same, but its volume, temperature, and other properties may change. In a constant pressure process, the system can exchange heat with its surroundings, but the pressure remains constant.
We can use Charles's Law to solve this problem, which states that at constant pressure, the volume of an ideal gas is directly proportional to its temperature in Kelvin.
We can set up a proportion:
(V₁/T₁) = (V₂/T₂)
where V₁ is the initial volume (5.31 L), T₁ is the initial temperature (200 K), V₂ is the final volume (what we want to find), and T₂ is the final temperature (300 K).
Solving for V₂:
V₂ = (V₁/T₁) x T₂
V₂ = (5.31 L / 200 K) x 300 K
V₂ = 7.965 L
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if a 0.25 m solution of a base is found to have a poh of 4.6 at equilibrium, what is the percent ionization of the base? select the correct answer below: 0.00010% 0.0010% 0.010% 0.10%
The percent ionization of the base is 0.010%. Option C is correct.
First, we can use the pOH value to find the pH of the solution;
pH + pOH = 14
pH = 14 - 4.6 = 9.4
Next, we can use the pH and the concentration of the solution to find the pKa of the conjugate acid of the base.
pH = pKa + log([A⁻]/[HA])
9.4 = pKa + log([A⁻]/[HA])
pKa = 9.4 - log([A⁻]/[HA])
Assuming the base is weak, we can also approximate the percent ionization using the equation;
% ionization = [A⁻]/[HA] x 100
Since the solution is 0.25 M, we can assume that [HA] = 0.25 M - [A-]. Substituting these values into the equation above and using the pKa we calculated, we get;
% ionization = [A⁻]/[HA] x 100
% ionization = [A⁻]/(0.25 M - [A⁻]) x 100
% ionization = [tex]10^{(-pKa +pH)}[/tex] x 100
% ionization = [tex]10^{(-9.4+4.6)}[/tex] x 100
% ionization = 0.010%
Hence, C. is the correct option.
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--"The given question is incomplete, the complete question is
If a 0.25 m solution of a base is found to have a pOH of 4.6 at equilibrium, what is the percent ionization of the base? select the correct answer below: A) 0.00010% B) 0.0010% C) 0.010% D) 0.10%"--
when 7.5 x 10-4 g of koh is dissolved in 1.00 l of 1.0 x 10-10 m cu(no3)2, a precipitate of cu(oh)2 is formed. true or false? (ksp of cu(oh)2 is 2.2 x 10-20)
The given statement {When 7.5 x 10^-4 g of KOH is dissolved in 1.00 L of 1.0 x 10^-10 M Cu(NO3)2, a precipitate of Cu(OH)2 is formed} is True. This is because the Ksp of Cu(OH)2 (2.2 x 10^-20) is exceeded, leading to the formation of a precipitate. So the answer is true.
When 7.5 x 10-4 g of KOH is dissolved in 1.00 L of 1.0 x 10-10 M Cu(NO3)2, a precipitate of Cu(OH)2 is formed. This statement is true.
The equation is given below:
Cu(NO3)2 + 2KOH → Cu(OH)2 + 2KNO3, the given Ksp value for Cu(OH)2 is 2.2 x 10-20.
Molarity of Cu(NO3)2 is given by:
M = (1.0 x 10-10 mol/L) = moles of solute/L of solution= n/1.0 L1.0 x 10-10 = n/1.0 n = 1.0 x 10-10 mol
Amount of KOH is given by: Molarity of KOH = moles of solute/L of solution M = 7.5 x 10-4 g/(56.11 g/mol)/1.0 L= 1.336 x 10-5 mol/L, the balanced equation shows that the ratio of Cu(NO3)2 to KOH is 1:2.
Thus, moles of KOH = 2 x moles of Cu(NO3)2. Hence moles of Cu(NO3)2 = 1.0 x 10-10 mol/L x 1.0 L = 1.0 x 10-10 mol.
Moles of KOH = 2 x 1.0 x 10-10 mol = 2.0 x 10-10 mol.
Now we have the amount of both Cu(NO3)2 and KOH used in the reaction. The Ksp of Cu(OH)2 is given as 2.2 x 10-20.
The formula of Ksp is;
Ksp = [Cu2+][OH-]2Cu2+ and OH- are produced in a 1:2 molar ratio according to the balanced equation.
Therefore, [Cu2+] = 1.0 x 10-10 mol/L and [OH-] = 2 x 2.0 x 10-10 mol/L = 4.0 x 10-10 mol/L.
The value of Ksp is calculated as follows:
Ksp = [Cu2+][OH-]2= (1.0 x 10-10 mol/L)(4.0 x 10-10 mol/L)2= 1.6 x 10-28 mol3/L3.
This Ksp value is less than the given Ksp of Cu(OH)2 (2.2 x 10-20), which implies that a precipitate of Cu(OH)2 will form, and the statement is true.
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what is the ph of the buffer that results when 12.5 g of nah2po4 and 22.0 g na2hoi4 are mixed and diluted with water to 0.5 l?
The pH of the buffer that results when 12.5 g of [tex]NaH_{2}PO_{4}[/tex] and 22.0 g [tex]Na_{2}HPO_{4}[/tex] are mixed and diluted with water to 0.5 L is 9.36. A buffer is a solution that resists changes in pH as acids or bases are added to it. It is created from a weak acid or base and one of its salts.
To calculate the pH of a buffer, we can use the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]) where: pH is the pH of the buffer pKa is the acid dissociation constant of the weak acid[A-] is the concentration of the conjugate base of the weak acid[HA] is the concentration of the weak acid.
According to the problem, 12.5 g of [tex]NaH_{2}PO_{4}[/tex] and 22.0 g [tex]Na_{2}HPO_{4}[/tex] are mixed and diluted with water to 0.5 L. The molecular weight of [tex]NaH_{2}PO_{4}[/tex] is 120 g/mol. Therefore, the number of moles of [tex]NaH_{2}PO_{4}[/tex] is:12.5 g × 1 mol/120 g = 0.104 mol The molecular weight of [tex]Na_{2}HPO_{4}[/tex] is 142 g/mol.
Therefore, the number of moles of [tex]Na_{2}HPO_{4}[/tex] is:22.0 g × 1 mol/142 g = 0.155 mol The total concentration of the buffer is the sum of the concentrations of the weak acid and its conjugate base. Therefore, the concentration of [tex]NaH_{2}PO_{4}[/tex] is:0.104 mol/0.5 L = 0.208 M The concentration of [tex]Na_{2}HPO_{4}[/tex] is:0.155 mol/0.5 L = 0.31 M The pKa of [tex]NaH_{2}PO_{4}[/tex] is 7.21.The concentration of the weak acid [HA] is 0.208 M.
The concentration of the conjugate base [A-] is 0.31 M.pH = pKa + log([A-]/[HA])= 7.21 + log(0.31/0.208)= 9.36The pH of the buffer that results when 12.5 g of [tex]NaH_{2}PO_{4}[/tex] and 22.0 g [tex]Na_{2}HPO_{4}[/tex] are mixed and diluted with water to 0.5 L is 9.36.
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Determine the heat absorbed by 1.5 moles of glycerol when its temperature increases from 25°C to 70°C. The molar mass of glycerol (C3H803) is 92.09 g/mol.
As a result, 1.5 moles of glycerol absorb about 1.99 Joules of heat when their temperature rises from 25 to 70 degrees Celsius.
What is C3H8O3 also known as?Glycerin is a straightforward polymer. The molecular formula of this solvent is C3H8O3. It is sometimes referred to as glycerine or glycerol.
We can use the following formula to determine how much heat 1.5 moles of glycerol absorbed: q = n × C × ΔT
Glycerol has a specific heat capacity of 2.43 J/g°C. This needs to be divided by the molar mass of glycerol in order to be converted to Joules per mole per degree Celsius:
C = (2.43 J/g°C) / (92.09 g/mol)
C = 0.0264 J/mol°C
The change in temperature can then be calculated as follows:
ΔT = (70°C - 25°C) = 45°C
We can now enter the values into the formula as follows:
q = (1.5 mol) × (0.0264 J/mol°C) × (45°C)
q = 1.99 J
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you dissolve of the aminoacid leucine in a solution with . select the structure of the predominant form of the amino acid in solution?
Option a. CH, NH, CH, H-O. O. The predominant form of leucine in a physiological buffer with pH 7.40 is its zwitterionic form.
The predominant form of the amino acid leucine in a buffer with physiological pH (7.40) would be in its zwitterionic form, also known as the dipolar ion.
In this form, the amino group (-NH3+) is protonated and the carboxyl group (-COO-) is deprotonated, resulting in a molecule with both positive and negative charges. This zwitterionic form is more stable than the neutral or charged forms of the amino acid in aqueous solution due to the interactions between the charged functional groups.
The specific structure of leucine in its zwitterionic form can be represented as NH3+CH(CH3)CH2CH(NH2)COO-. Therefore, the answer would be option (a) CH3CH(NH3+)CH2COO-.
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The complete question is:
You dissolve 0.1 mol of the amino acid leucine in a buffer with physiological pH (7.40) and make 1L of solution. Select the structure of the predominant form of the amino acid in solution? NH, но, Q-COOH a-NH3 Leucine pl 2.32 9.58 ΝΗ, CH O (a) CH, NH, CH, H-O. O (b) wy CH ΝΗ, CH H-O O(C) CH NH' CH, O (d) yer CH
14. Activities in the human body are represented in the diagram below Heat released from body by blood vessels dilating or by sweating Blood temperature decreases L Signals via blood ୮ Blood temperature increases L Brain Skin Skin Heat conserved by blood vessels constricting or by not sweating (Not drawn to scale) alel Ĵ "Too hot" Signals to skin via nerves "Too cold" Source: Campbell and Reece, Biology, 6th edition (adapted) Which title would be appropriate for the diagram? A) Rate of Excretion Varies in Response to Amount of Water Taken In B) Feedback Mechanisms Help to Maintain Homeostasis C) Respiratory Rate Responds to an Increase in Muscle Activity D) The Nervous System Responds to Changes in Blood Sugar Levels
Heat manufacturing is a feature of metabolism. Most of the warmth produced in the body is generated in the liver, brain, heart, and skeletal muscle mass all through exercise.
What is the technique through which warmness is produced in human body?In our body, cellular respiration leads to formation of water, carbon dioxide and launch of energy. This energy is stored in the shape of ATP. Some structure of this strength is utilised in day by day things to do and the excess is launched in the form of heat.
Which of the following is the method in which heat is misplaced from the body as wind passes over it?Cooling Your Body
Convection happens when warmness is carried away from your body by means of shifting air. If the surrounding air is cooler than your skin, the air will absorb your heat and rise.
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25.0 ml of 0.212 m naoh is neutralized by 13.6 ml of an hcl solution. the molarity of the hcl solution is . group of answer choices 0.115 m 0.212 m 0.137 m 0.390 m 0.500 m
The molarity of the HCl solution is approximately 0.390 M.
To find the molarity of the HCl solution, you can use the formula:
Molarity of acid(M2) x Volume of acid(V2) = Molarity of base(M1) x Volume of base(V1)
Molarity of acid(M2) = (Molarity of base(M1) x Volume of base(V1)) / Volume of acid(V2)
Therefore,
M1V1 = M2V2
where M1 and V1 are the molarity and volume of NaOH, and M2 and V2 are the molarity and volume of HCl.
Given:
M1 = 0.212 M (NaOH)
V1 = 25.0 mL (NaOH)
V2 = 13.6 mL (HCl)
You need to find M2 (molarity of HCl).
Step 1: Rearrange the formula to solve for M2:
M2 = (M1V1) / V2
Step 2: Plug in the given values:
M2 = (0.212 M * 25.0 mL) / 13.6 mL
Step 3: Calculate the result:
M2 ≈ 0.390 M
So, the molarity of the HCl solution is approximately 0.390 M.
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what is the ph of a solution at the midpoint during the titration of 0.1656 m vh3cooh with 0.1612 m koh
The pH of the solution at the midpoint is 4.76. To find the pH of the solution at the midpoint of the titration, we need to determine the equivalence point, which is the point at which the number of moles of acid equals the number of moles of base.
The balanced chemical equation for the reaction is:
VH3COOH + KOH → KH2COO- + H2O
From the equation, we can see that the stoichiometric ratio of VH3COOH to KOH is 1:1. Therefore, at the equivalence point, the number of moles of VH3COOH will be equal to the number of moles of KOH.
The number of moles of VH3COOH in the original solution can be calculated as:
moles of VH3COOH = 0.1656 M × V1 L
where V1 is the volume of VH3COOH in liters.
At the equivalence point, the number of moles of KOH added will be equal to the number of moles of VH3COOH in the original solution:
moles of KOH = 0.1612 M × Veq L
where Veq is the volume of KOH required to reach the equivalence point.
Setting the two expressions equal to each other and solving for Veq, we get:
0.1656 M × V1 L = 0.1612 M × Veq L
Veq = (0.1656 M × V1 L) / (0.1612 M)
Veq = 1.071 L
At the midpoint of the titration, half of the acid has been neutralized, which means that the number of moles of VH3COOH is half the number of moles in the original solution. Therefore, the number of moles of VH3COOH at the midpoint is:
moles of VH3COOH = 0.5 × 0.1656 M × V1 L = 0.0828 M × V1 L
The number of moles of KOH required to reach the midpoint is half the number of moles required to reach the equivalence point:
moles of KOH = 0.5 × 0.1612 M × Veq L = 0.0408 M × Veq L
At the midpoint, the moles of acid remaining equals the moles of base added. Therefore:
moles of VH3COOH = moles of KOH
0.0828 M × V1 L = 0.0408 M × 1.071 L
V1 = 0.503 L
Now we can calculate the concentration of the acid at the midpoint:
acid concentration = 0.1656 M × 0.503 L / 1 L = 0.0833 M
To find the pH at the midpoint, we need to use the acid dissociation constant (Ka) of VH3COOH, which is 1.74 × 10^-5 at 25°C. The Henderson-Hasselbalch equation can be used to calculate the pH:
pH = pKa + log([A^-] / [HA])
At the midpoint, [A^-] = [HA] because we are at half-neutralization. Therefore:
pH = pKa + log(1) = pKa = -log(1.74 × 10^-5) = 4.76
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each of the following is one of the major classes of outdoor pollutants except (mark all that apply) group of answer choices carbon oxides suspended particles nitrogen oxides sulfur oxides smog
Smog is a result of the interaction between different pollutants, it does not belong to the major classes of outdoor pollutants.
Let me briefly explain each major class of outdoor pollutant:
1. Carbon oxides: This group includes carbon monoxide (CO) and carbon dioxide (CO2). Carbon monoxide is a toxic gas produced by the incomplete combustion of fuels, while carbon dioxide is a greenhouse gas released from various human activities like the burning of fossil fuels.
2. Suspended particles: These are tiny solid or liquid particles suspended in the air, also known as particulate matter (PM). They can be emitted from various sources like construction activities, vehicle emissions, and industrial processes. Suspended particles can cause respiratory issues and other health problems.
3. Nitrogen oxides: This group includes nitrogen dioxide (NO2) and nitric oxide (NO), which are mainly emitted from vehicle exhausts and industrial processes. Nitrogen oxides contribute to the formation of smog, acid rain, and can cause respiratory problems.
4. Sulfur oxides: Sulfur dioxide (SO2) is the primary sulfur oxide, and it is released from burning fossil fuels, especially coal and oil, and from industrial processes. Sulfur oxides contribute to the formation of acid rain and can also cause respiratory problems.
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what is the uncertainty in the molarity of your edta titrant? show your worked out solution in the space provided below and enter your final answer for standard deviation and percent relative standard deviation.
The standard deviation and per cent relative standard deviation, which represent the uncertainty in the molarity of your EDTA titrant.
To calculate the uncertainty in the molarity of your EDTA titrant, we need some information about the measurements taken during the titration process. However, since the information is not provided, I will give you a general step-by-step guide to finding the uncertainty in molarity:
1. Record the volume measurements (in mL) for each titration trial.
2. Calculate the molarity of the EDTA titrant for each trial using the balanced equation of the reaction and the known molarity and volume of the analyte solution.
3. Find the mean (average) molarity of the EDTA titrant by summing the molarities calculated in step 2 and dividing by the total number of trials.
4. Calculate the deviation for each trial by subtracting the mean molarity from the molarity of each trial.
5. Square each deviation calculated in step 4.
6. Sum the squared deviations and divide by the total number of trials minus one (n-1) to find the variance.
7. Calculate the standard deviation by taking the square root of the variance.
8. Calculate the per cent relative standard deviation by dividing the standard deviation by the mean molarity and multiplying by 100.
After following these steps, you will have found the standard deviation and per cent relative standard deviation, which represents the uncertainty in the molarity of your EDTA titrant.
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what do you still think about what determines the Moon's appearance from Earth?
Answer:
I think that the moon's rotation around the Earth shows us different parts of the moon
Explanation:
Answer:
The biggest clue to why the Moon always looks different when you look up at the sky is that it is constantly moving in relation to Earth and the Sun.
Explanation:
Which of the following is a non-volatile solute? Select all that apply.
2-propanol (rubbing alcohol)
Methanol
Sodium chloride
Sugar
What is the aqueous solubility of He at 1 atm and at 20°C? The solubility of He at 20°C is 0.00037 mol/L/atm.
Answer in units of mg/L.
The aqueous solubility of He at 1 atm and 20°C is 0.0928 mg/L. To convert the aqueous solubility of He from mol/L/atm to mg/L, we need to consider the molar mass of He, which is approximately 4.003 g/mol.
The conversion factor we need is:
1 mol He / (4.003 g He) x 1000 mg / 1 g = 249.8 mg He / mol He
Using the given solubility of He at 20°C (0.00037 mol/L/atm), we can calculate the aqueous solubility of He at 1 atm and 20°C:
Aqueous solubility of He = (0.00037 mol/L/atm) x (1 atm) x (249.8 mg He/mol He)
Aqueous solubility of He = 0.0928 mg/L
Therefore, the aqueous solubility of He at 1 atm and 20°C is 0.0928 mg/L.
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indicate if each of the following errors is systematic, random or human mistake based on how they affect the results of the lab: group of answer choices each solution absorbs carbon dioxide from the air, making them slightly more acidic [ choose ] estimating the amount of each salt to dissolve in the distilled water [ choose ] spilling some salt during the transfer into the centrifuge tube [ choose ] inconsistent volume in drops of indicator [ choose ] using dirty test tubes [ choose ]
Amoung the following errors 1, 2 and 5 are systemic error and 3,4 are random error.
1- Each solution absorbs carbon dioxide from the air, making them slightly more acidic: This is a systematic error because it affects all samples uniformly and consistently, causing a bias in the results.
2- Estimating the amount of each salt to dissolve in the distilled water: This could be either a systematic or a human error, depending on how the estimation is made. If the estimation is done using a consistent and repeatable method, it could be considered a systematic error. However, if the estimation is done inconsistently or based on subjective judgment, it would be a human error.
3- Spilling some salt during the transfer into the centrifuge tube: This is a random error because it affects only some samples and introduces variability in the results.
4- Inconsistent volume in drops of indicator: This is a random error because it affects only some samples and introduces variability in the results.
5- Using dirty test tubes: This could be either a systematic or a human error, depending on the cause of the dirtiness. If the dirtiness is due to a consistent and repeatable factor, such as inadequate cleaning, it would be a systematic error. However, if the dirtiness is due to a one-time event, such as accidental contamination, it would be a random error.
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Make a prediction you think is happening to the coral reefs if the concentration of salt increases or decreases.
Coral islands might be negatively impacted if the ocean's salinity level were to rise. Since corals have evolved to exist in a very narrow range of salinity, a rise in salt concentration might make them stressed or even kill them.
However, since corals need a certain amount of salinity to keep their internal water balance, a drop in salt concentration could also be harmful.
While salinity variations do not pose the greatest danger to coral reefs, they can undoubtedly affect their health and should be watched closely along with other environmental factors.
Coral reef survival and health depend heavily on salinity or the amount of salt in the ocean. Corals have developed to exist in a particular range of salinities, and changes outside of that range may have a detrimental effect on their capacity to endure and flourish.
The surrounding water may become too salty for the corals to endure if the concentration of salt increases, as might be the case due to human activities like salt mining or seawater desalination.
This could make them stressed out and more prone to illness, bleaching, or even mortality. Contrarily, a decrease in salt concentration, such as that caused by freshwater runoff, can make the water too diluted for the corals to keep their internal water balance, which can also lead to stress and other negative effects.
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1. For the reaction C + 2H2 → CH4, how many moles of carbon are needed to make 174.6 grams of methane, CH4 ?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:
Element
Molar Mass
Hydrogen
1
Carbon
12
2. 3 Cu + 8HNO3 --> 3 Cu(NO3)2 + 2 NO + 4 H2O
In the above equation how many moles of water can be made when 110.2 grams of HNO3 are consumed?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:
Element
Molar Mass
Hydrogen
1
Nitrogen
14
Copper
63.5
Oxygen
16
10.91 moles of carbon are needed to make 174.6 grams of methane.
0.9 moles of water can be made when 110.2 grams of HNO3 are consumed.
First, we need to calculate the number of moles of methane produced from the given mass.
Molar mass of CH4 = 12 + 4(1) = 16 g/mol
Number of moles of CH4 = 174.6 g / 16 g/mol = 10.91 mol (rounded to two decimal places)
According to the balanced chemical equation, 1 mole of carbon is required to produce 1 mole of CH4. Therefore, the number of moles of carbon required can be calculated as follows:
Number of moles of C = 10.91 mol × 1 mol C / 1 mol CH4 = 10.91 mol (rounded to two decimal places)
We need to use the given balanced chemical equation to determine the stoichiometry of the reaction between Cu and HNO3, and then use the molar mass of HNO3 to calculate the number of moles consumed and the number of moles of water produced.
According to the balanced chemical equation, 8 moles of HNO3 react to produce 4 moles of H2O. Therefore, the ratio of moles of HNO3 to moles of H2O is 8:4, or 2:1.
Number of moles of HNO3 = 110.2 g / 63.5 g/mol = 1.737 mol (rounded to three decimal places)
Number of moles of H2O = 1.737 mol / 2 = 0.869 mol (rounded to three decimal places).
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