The correct student with scientific reasoning is the first student who states that the percent error could be caused by the salt not completely dissolving, which would result in a lower measured change in heat per mole. This is a valid scientific reasoning as the dissolving of the salt is an important factor that affects the change in heat during the reaction.
The percent error could be caused by the salt not completely dissolving, therefore the change in heat per mole would be accidentally low. The percent error could be caused by mixing the reaction too quickly, the friction caused by mixing would increase the change in heat measured. The percent error could be caused by the change in pH of the solution, this would decrease the change in heat accidentally.
The second student's statement that the percent error could be caused by mixing the reaction too quickly is not a valid scientific reasoning, as mixing does not affect the change in heat produced by the reaction.
The third student's statement that the percent error could be caused by the change in pH of the solution decreasing the change in heat is also not a valid scientific reasoning, as a change in pH would not affect the change in heat produced by the reaction.
Therefore, the first student provides the correct scientific reasoning for the possible cause of the percent error in the lab.
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What happens to the surroundings during an endothermic reaction?
Answer: The surroundings will lower in temperature.
Explanation:
Endothermic reactions draw heat from the surroundings in order to occur. So the surroundings will feel cold, as the heat is being used as energy in the reaction.
describe the reaction that replenishes nad . name the reactants that get reduced and oxidized. what are the products, and where do they go next
Tthe reaction that replenishes( NAD+) involves the oxidation of NADH and the reduction of oxygen. The products are( NAD+), water, and ATP, which are then used in various cellular processes.
The reaction that replenishes( NAD+) is called cellular respiration, specifically, the oxidation of NADH back to( NAD+). This process occurs in the electron transport chain, which is a part of cellular respiration. The products are (NAD+), water, and ATP, which are then used in various cellular processes.
In this reaction, NADH is oxidized, meaning it loses electrons, and returns to its original form, (NAD+). This is essential for maintaining the balance of (NAD+ )and NADH in the cell and ensuring that glycolysis, the citric acid cycle, and other cellular processes can continue.
The reactant that gets reduced is oxygen (O2). Oxygen is the final electron acceptor in the electron transport chain and is essential for aerobic respiration. When oxygen accepts electrons, it is reduced to form water ([tex]H2O[/tex]).
The products of this reaction are ([tex]NAD+[/tex]), water, and energy in the form of ATP.( NAD+) is recycled and can be used again in glycolysis and the citric acid cycle to help generate more ATP. Water is a byproduct of the reaction and can be used for various cellular processes or excreted as waste.
The ATP generated is used as a source of energy for various cellular activities, including growth, maintenance, and repair.
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if 0.090 mole of solid naoh is added to 1.0 liter of 0.180 m ch3cooh, what will the ph of the resulting solution be?
If 0.090 mole of solid NaOH is added to 1.0 liter of 0.180 m [tex]CH_3COOH[/tex]. The pH of the resulting solution is 4.74.
To solve this problem, we need to use the equation for the dissociation of acetic acid:
[tex]CH_3COOH + H_2O[/tex]⇌ [tex]CH_3COO^{-} + H_3O^+[/tex]
The addition of solid NaOH will react with the acetic acid to form sodium acetate and water:
[tex]CH_3COOH + NaOH[/tex] → [tex]CH_3COO^{-} Na^{+} + H_2O[/tex]
To calculate the pH of the resulting solution, we need to determine the new concentrations of [tex]CH_3COOH[/tex]and [tex]CH_3COO^-[/tex]. We can use the initial concentration of [tex]CH_3COOH[/tex]and the amount of NaOH added to calculate the new concentration of [tex]CH_3COOH[/tex]:
moles of [tex]CH_3COOH[/tex]= initial concentration x volume = 0.180 M x 1.0 L = 0.180 moles
moles of NaOH = 0.090 moles
moles of [tex]CH_3COOH[/tex]remaining = 0.180 moles - 0.090 moles = 0.090 moles
volume of solution = 1.0 L + 0.090 L = 1.090 L
new concentration of [tex]CH_3COOH[/tex]= moles / volume = 0.090 moles / 1.090 L = 0.0826 M
Since NaOH is a strong base, it will completely dissociate in water to form [tex]Na^+[/tex] and [tex]OH^-[/tex]. The [tex]OH^-[/tex] ions will react with the remaining [tex]CH_3COOH[/tex]to form [tex]CH_3COO^-[/tex], so the new concentration of [tex]CH_3COO^-[/tex] will be equal to the moles of NaOH added:
new concentration of [tex]CH_3COO^-[/tex] = 0.090 moles / 1.090 L = 0.0826 M
Now we can use the equilibrium expression for the dissociation of acetic acid to calculate the pH of the buffer:
[tex]Ka = [CH_3COO^{-}][H_3O^{+}] / [CH_3COOH]\\[H_3O^{+}] = Ka * [CH_3COOH] / [CH_3COO^{-}]\\[H_3O^{+}] = 1.8 * 10^{-5} * 0.0826 M / 0.0826 M\\[H_3O^{+}] = 1.8 * 10^{-5} M\\pH = -log[H_3O^{+}]\\pH = -log(1.8 * 10^{-5})\\pH = 4.74[/tex]
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according to the galvanic cell video provided in the introduction page of this module, which statement is true about the four main parts of the galvanic cell? group of answer choices the anode is the electrode that receives electrons. an external circuit with a multimeter will be used to transfer electrons. there are two electrodes and they will be immersed in the same metal solutions. the cathode is the electrode where oxidation occurs. salt bridge will only be placed in one of the cells.
According to galvanic cell video which is provided in the introduction page of this module, the statement which is true about the four main parts of the galvanic cell will be; "The cathode will be the electrode where reduction can occurs." Option D is correct.
A galvanic cell, also termed as a voltaic cell, in an electrochemical cell which uses a spontaneous redox reaction to generate an electric current. The cell consists of two half-cells, each containing an electrode and an electrolyte solution. The two half-cells are connected by a wire as well as a salt bridge.
The other statements are not correct; The anode is the electrode where oxidation occurs, not where it receives electrons.
An external circuit with a voltmeter (not multimeter) is used to measure the potential difference (voltage) between the two electrodes.
There are two electrodes, but they are immersed in different solutions (not the same metal solutions).
The salt bridge is placed in both cells to allow the flow of ions to maintain electrical neutrality, not just in one cell.
Hence, D. is the correct option.
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--The given question is incomplete, the complete question is
"According to the galvanic cell video provided in the introduction page of this module, which statement is true about the four main parts of the galvanic cell? group of answer choices A) the anode is the electrode that receives electrons. B) an external circuit with a multimeter will be used to transfer electrons. C) there are two electrodes and they will be immersed in the same metal solutions. D) the cathode is the electrode where oxidation occurs. E) salt bridge will only be placed in one of the cells."--
a buffer can not be destroyed by adding too much strong base. it can only be destroyed by adding too much strong acid. false 2. adding 0.1 mol solid naoh to a 1.0 l of 0.2 m hcl solution could prepare a buffer. false 3. adding a small amount of acid to a buffer increases the ph of the buffer.
The following statements on solutions, the following are as, 1- false. 2- false. 3- false.
1. The statement "a buffer can not be destroyed by adding too much strong base. it can only be destroyed by adding too much strong acid" is false. While it is true that buffers are most commonly used to resist changes in pH caused by the addition of strong acid, adding too much strong base can also destroy a buffer.
This is because a buffer works by containing both a weak acid and its conjugate base (or a weak base and its conjugate acid). If too much strong base is added to a buffer, it can convert the weak acid to its conjugate base, removing the buffer capacity.
2. The statement "adding 0.1 mol solid naoh to a 1.0 l of 0.2 m hcl solution could prepare a buffer" is false. In order to prepare a buffer, you need to have both a weak acid and its conjugate base (or a weak base and its conjugate acid) present in the solution.
The addition of NaOH to HCl will only create a strong acid-base reaction that will result in the formation of salt and water.
3. The statement "adding a small amount of acid to a buffer increases the ph of the buffer" is also false. When a small amount of acid is added to a buffer, the buffer will resist the change in pH caused by the addition of the acid.
This is because the buffer contains both a weak acid and its conjugate base (or a weak base and its conjugate acid), which can neutralize the added acid. As a result, the pH of the buffer will remain relatively unchanged.
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a. it is impossible to anticipate the ph profile of an acid and base without performing the experiment in the lab. b. the ph profile is expected to behave similarly to the example of hydrochloric acid and sodium hydroxde provided in the lab manual. c. the ph profile is expected to behave similarly to the example of acetic acid and sodium hydroxide provided in the lab manual. d. the identity of the acid does not play a role in determining the ph profile of the reaction between an acid and a base.
Answer:
a. it is impossible to anticipate the pH profile of an acid and base without performing the experiment in the lab.
Explanation:
Ammonia and gaseous hydrogen chloride combine to form ammonium chloride according to this equation:
NH3(g) + HCl(g) → NH4Cl(s)
If 4.21 L of NH3(g) at 27°C and 1.02 atmospheres is combined with 5.35 L of HCl(g) at 26°C and 0.998 atmospheres, what mass of NH4Cl(s) will be produced? Which gases are the limiting and excess reactants?
Explanation:
To solve this problem, we first need to calculate the number of moles of NH3 and HCl using the ideal gas law:
n = PV / RT
where:
P = pressure in atmospheres
V = volume in liters
T = temperature in kelvins
R = 0.08206 L atm/mol K (the ideal gas constant)
For NH3:
n(NH3) = (1.02 atm) (4.21 L) / (0.08206 L atm/mol K) (300 K)
n(NH3) = 0.177 mol
For HCl:
n(HCl) = (0.998 atm) (5.35 L) / (0.08206 L atm/mol K) (299 K)
n(HCl) = 0.204 mol
From the balanced equation, we can see that the stoichiometry of NH3 to HCl is 1:1, so NH3 is the limiting reactant since it has fewer moles. The balanced equation also tells us that the ratio of NH3 to NH4Cl is 1:1, so the number of moles of NH4Cl produced is also 0.177 mol.
To calculate the mass of NH4Cl produced, we need to use the molar mass of NH4Cl:
M(NH4Cl) = 14.01 g/mol (N) + 4(1.01 g/mol) (H) + 35.45 g/mol (Cl)
M(NH4Cl) = 53.49 g/mol
mass(NH4Cl) = n(NH4Cl) × M(NH4Cl)
mass(NH4Cl) = 0.177 mol × 53.49 g/mol
mass(NH4Cl) = 9.48 g
Therefore, the mass of NH4Cl produced is 9.48 g.
To determine the excess reactant, we can calculate how much of each reactant is consumed based on the stoichiometry of the reaction. Since NH3 and HCl react in a 1:1 ratio, we can assume that all of the NH3 is consumed, so we need to calculate the amount of HCl that is consumed:
n(HCl) consumed = n(NH3) = 0.177 mol
n(HCl) initially = (0.998 atm) (5.35 L) / (0.08206 L atm/mol K) (299 K)
n(HCl) initially = 0.204 mol
n(HCl) excess = n(HCl) initially - n(HCl) consumed
n(HCl) excess = 0.204 mol - 0.177 mol
n(HCl) excess = 0.027 mol
To convert this to a volume, we can use the ideal gas law:
V(HCl) excess = n(HCl) excess × RT / P
V(HCl) excess = 0.027 mol × (0.08206 L atm/mol K) (299 K) / (0.998 atm)
V(HCl) excess = 0.686 L
Therefore, the excess reactant is HCl, and the limiting reactant is NH3.
What is the freezing point in ºC of a 2.20 molal solution of lithium bromide in water?
Hence, a 2.20 molal solution of lithium bromide in water has a freezing point that is roughly -0.00409 °C.
What is water-based lithium bromide solution?In absorption refrigeration systems, the bromide lithium water (LiBr/H2O) solution is frequently employed as the working fluid since it is nonvolatile, nontoxic, and does not deplete the ozone layer.
We can use the following formula to get a solution's freezing point depression: ΔTf = Kf * molality
1.86 °C/m is the freezing point depression constant for water.
Inputting the values provided yields:
molality = 2.20 mol of LiBr / 1000 g of water
molality = 0.00220 mol/g
ΔTf = (1.86°C/m) * (0.00220 mol/g)
ΔTf = 0.00409°C
The freezing point of the solution is:
freezing point = 0°C - ΔTf
freezing point = 0°C - 0.00409°C
freezing point = -0.00409°C
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Give 2 processes in which particles will lose or gain energy.
The 2 processes in which the particles will lose or gain energy are:
1) Temperature Change Or
2) State Change
A particle losses or gains energy when its Temperature changes i.e. A vessel filled with boiling water (100 degrees C ) cools down at the room temperature OR
when its State changes i.e. A bucket full of ice is kept at a room temperature (state changes from Solid to Liquid)
It is because of the breaking or formation of bonds, which results in loss or gain in energy.
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aluminum is produced commercially by the electrolysis of al2o3 in the presence of a molten salt. if a plant has a continuous capacity of 1.15 million amp, what mass of aluminum can be produced in 2.40 h?
The mass of aluminum that can be produced in 2.40 h is 1390 kg aluminum production by Electrolysis.
The amount of aluminum produced can be calculated using Faraday's law, which states that the amount of substance produced is directly proportional to the amount of electric charge passed through the cell, and the molar mass of the substance.
The balanced chemical equation for the electrolysis of [tex]Al_2O_3[/tex] is:
[tex]2 Al_2O_3(l)[/tex] -> [tex]4 Al(l) + 3 O_2(g)[/tex]
From the equation, we see that for every 4 moles of aluminum produced, 6 moles of electrons are needed.
The charge passed through the cell can be calculated using the formula:
charge = current × time
Where current is measured in amperes (A) and time is measured in hours (h). We need to convert 2.40 h to seconds:
[tex]2.40* 3600 = 8640 s[/tex]
The charge passed through the cell is:
charge = 1.15 million A × 8640 s = [tex]9.936 * 10^9[/tex] C
The number of moles of electrons passed through the cell can be calculated as:
moles of electrons = charge / Faraday's constant
Where Faraday's constant is 96,485 C/mol.
moles of electrons = [tex]\frac{9.936 * 10^9}{96,485} = 103,068[/tex] mol
Therefore, the number of moles of aluminum produced is half of the number of moles of electrons, or:
moles of Al = 0.5 × (103,068 mol) = 51,534 mol
The mass of aluminum produced can be calculated using the molar mass of aluminum, which is 26.98 g/mol:
mass of Al = moles of Al × molar mass of Al
mass of Al = [tex]51,534 * 26.98 = 1.39 * 10^6[/tex] g or 1390 kg
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suppose a student conducted a titration of an unknown solution of the weak acid ch3cooh with 0.880 m naoh. first, the student diluted 15.0 ml of the ch3cooh solution with 85.0 ml of water in an erlenmeyer flask and added 2 drops of the indicator, phenolphthalein. then, 0.880 m naoh was titrated into the diluted ch3cooh solution until the color of the solution changed to pink and the end point of the titration was reached. at the end point, 6.80 ml of 0.880 naoh was added to the ch3cooh solution. calculate the concentration of the ch3cooh solution.
The concentration of the CH₃COOH solution is 0.0399 M.
The balanced chemical equation for the reaction between CH₃COOH and NaOH is:
CH₃COOH + NaOH → CH₃COONa + H₂O
From the equation, it can be seen that one mole of NaOH reacts with one mole of CH₃COOH. Therefore, the number of moles of NaOH used in the titration is:
0.880 mol/L × 0.00680 L = 0.00598 mol
Since the dilution did not affect the number of moles of CH₃COOH, the number of moles of CH₃COOH in the original solution is also 0.00598 mol.
The volume of the original solution used in the titration is:
15.0 mL/100.0 mL = 0.15
Therefore, the concentration of the CH3COOH solution is:
0.00598 mol/0.15 L = 0.0399 M
As a result, the CH₃COOH solution has a concentration of 0.0399 M.
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what is the enthalpy of combustion of a compound if it's enthalpy of formation is -520 KJ/mol and if the total enthaply of formation of its products is -670 KJ/mol
Answer:
Thus, to yield the enthalpy of the combustion reaction, we then sum the enthalpies of formation of the products, weighted by their stoichiometric coefficients, and subtract the enthalpy of formation of ethanol (-277.69kJ/mol). The result is ethanol's standard enthalpy of combustion of -1234.79kJ/mol.
a student performs three titrations in order to standardize a naoh solutions. the results are: 0.105 m, 0.0990 m, 0.110 m. calculate the average and the standard deviation. are the results acceptable, or should she perform more titrations?
The average of the three titrations is 0.104 m.
The standard deviation is 0.0055
The average of the three titrations is as follows:
(0.105 + 0.0990 + 0.110) / 3 = 0.104 m.
To calculate the standard deviation, we first need to calculate the variance. The variance is the sum of the squared differences from the mean, divided by the number of measurements minus one. Using the formula for variance, we get:
Variance = [(0.105 - 0.104)² + (0.0990 - 0.104)² + (0.110 - 0.104)²] / (3 - 1)
= 3.05 x 10⁻⁵
The standard deviation is the square root of the variance, which is:
standard deviation = √(3.05 x 10⁻⁵) = 0.0055
The standard deviation is relatively small compared to the average, indicating that the results are precise. However, we cannot determine if the results are accurate without knowing the true value of the NaOH solution concentration. Therefore, we need to compare the average to the expected value or to a certified reference material.
If the average is within an acceptable range of the expected value or certified reference material, then the results are acceptable. Otherwise, more titrations should be performed to increase the precision and accuracy of the measurements. It is recommended to consult with a teacher or a supervisor to determine the appropriate number of titrations needed for the specific experiment.
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ernest rutherford's experiments in which alpha rays pass through a thin piece of metal foil demonstrated that group of answer choices neutrons exist. the atom contains a tiny nucleus containing most of the atom's mass. light is made of particles. electrons exist. light is a wave.
Ernest Rutherford's experiments in which alpha rays pass through a thin piece of metal foil demonstrated that atom contains a tiny nucleus containing most of the atom's mass. The correct answer choice is "the atom contains a tiny nucleus containing most of the atom's mass."
The alpha-particle scattering experiment was performed by Ernest Rutherford in 1911. It was conducted to discover the nature of atomic structure. The experiment demonstrated that most of the mass of an atom and all of its positive charge are contained in a small nucleus at the center of the atom.
The electrons were found to occupy almost all of the remaining space. Therefore, the correct answer is the atom contains a tiny nucleus containing most of the atom's mass.
Therefore "the atom contains a tiny nucleus containing most of the atom's mass." is the correct answer.
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Suppose only 5,550J heat was used to warm up the same 55.0g of water. If the water started out at 25 degrees celsius what would its final temperature become?
Answer:
What is the heat in joules required to raise the temperature of 25 grams of water from 0 degrees C to 100 degrees C? What is the heat in calories? Answer: 10450 J or 2500 calories of heat energy are required to raise the temperature of 25 grams of water from 0 degrees C to 100 degrees C.
Rank the following bonds from highest polarity to the lowest:
1 = most polar ; 4 = least polar
N--Si [ Select ] ["1", "2", "3", "4"]
O--Cl [ Select ] ["1", "2", "3", "4"]
C--S [ Select ] ["1", "2", "3", "4"]
H--N [ Select ] ["1", "2", "3", "4"]
The order of bonds from highest polarity to the lowest is:1. O--Cl2. H--N3. C--S4. N--Si
Polarity can be explained as the extent to which electron density is unevenly distributed between atoms within a molecule. This can result in the molecule having a partial positive or negative charge.
The polarity of the bond is decided by the electronegativity difference between the two atoms involved in the bond. If the difference is greater, the bond will be more polar.
O--Cl bond: Oxygen is more electronegative than chlorine, so the bond is polar. Hence, O--Cl has the highest polarity.
H--N bond: The difference in electronegativity between hydrogen and nitrogen is not as great as that between oxygen and chlorine, but it is still significant. Hence, H--N has the second-highest polarity.
C--S bond: The difference in electronegativity between carbon and sulfur is less significant, making the bond less polar. Hence, C--S has the third-highest polarity.
N--Si bond: The difference in electronegativity between nitrogen and silicon is the least significant of all the bonds given. Thus, N--Si has the lowest polarity.
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the second-order decomposition of no2 has a rate constant of 0.255 m-1s-1. how much no2 decomposes in 8.00 s if the initial concentration of no2 (1.00 l volume) is 1.33 m? the second-order decomposition of no2 has a rate constant of 0.255 m-1s-1. how much no2 decomposes in 8.00 s if the initial concentration of no2 (1.00 l volume) is 1.33 m? 0.85 mol 0.97 mol 1.66 mol 1.9 mol 0.36 mol
In 8.00 seconds, approximately 0.84 mol of NO2 decomposes. The closest answer among the given options is 0.85 mol.
To find out how much NO2 decomposes in 8.00 s given the initial concentration and rate constant, we can use the second-order reaction formula:
1/[A]t = kt + 1/[A]₀
Where:
- [A]t is the concentration of NO2 at time t (which we want to find)
- k is the rate constant (0.255 M⁻¹s⁻¹)
- t is the time (8.00 s)
- [A]₀ is the initial concentration of NO2 (1.33 M)
Step 1: Plug the values into the equation.
1/[A]t = (0.255 M⁻¹s⁻¹)(8.00 s) + 1/(1.33 M)
Step 2: Calculate the value on the right side of the equation.
1/[A]t = 2.04 M⁻¹
Step 3: Solve for [A]t (concentration of NO2 at 8.00 s).
[A]t = 1/2.04 M⁻¹ = 0.49 M
Step 4: Calculate the change in concentration (how much NO2 decomposes).
Change in concentration = [A]₀ - [A]t = 1.33 M - 0.49 M = 0.84 M
Step 5: Convert the change in concentration to moles (since the volume is 1.00 L, the change in concentration is equal to the change in moles).
Change in moles = 0.84 mol
So, the correct option is 0.85 as it is closest to the answer.
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what is the temperature of 1.2 moles of Helium gas at 1950mm Hg if it occupies 15,500 ml of volume?
The temperature of 1.2 moles of Helium gas at 1950 mm Hg if it occupies 15,500 ml of volume is 131°C.
We know we want to use the ideal gas law because we have the moles, pressure, and volume and we want to get the pressure: PV = nRT, where P = pressure, V = volume, n = number of moles, R = gas constant, and T = Kelvin temperature.
Here, the following values are given: 1950 mmHg of pressure, 15,500 mL (15.5 L), 1.2 mol of material, and R = 62.3638 (according to a table of gas constants). To the equation, include these:
Solve for temperature as follows: (1950) x (15.5 L) = (1.2) x (62.3638) x Temperature Temperature = 403.88 K.
We can convert this to degrees Celsius by subtracting 273 from the total:
3 sig figs = 403.88 - 273 = 130.88 - 131 (3 sig figs)
This causes the temperature to be 131°C.
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at the equivalence point for a weak acid-strong base titration, an equal number of h and oh- have reacted, producing a solution of water and salt. what affects the ph at the equivalence point for this kind of titration?
The pH at the equivalence point for a weak acid-strong base titration is affected by the dissociation constant of the weak acid and the hydrolysis of the resulting salt, leading to a pH above 7 at the equivalence point.
The pH at the equivalence point for a weak acid-strong base titration is affected by two main factors: the dissociation constant (Ka) of the weak acid and the hydrolysis of the resulting salt.
1. Dissociation constant (Ka) of the weak acid: The Ka represents the extent to which the weak acid ionizes in water. A smaller Ka value indicates a weaker acid, which means it ionizes less in solution. Since the equivalence point occurs when equal amounts of H+ and OH- ions have reacted, the degree of ionization of the weak acid will influence the pH of the solution.
2. Hydrolysis of the resulting salt: When a weak acid reacts with a strong base, a salt and water are formed. The anion of the salt, which is a conjugate base of the weak acid, can undergo hydrolysis, reacting with water to form a small amount of the weak acid and hydroxide ions (OH-). This hydrolysis increases the concentration of OH- ions in the solution, leading to a pH above 7 at the equivalence point.
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Find the mass, in grams, of 11.2 L H2.
The mass of 11.2 L of H2 gas at STP is 1.008 grams.
To find the mass of hydrogen gas in 11.2 L, we need to use the ideal gas law, which relates the pressure (P), volume (V), number of moles (n), and temperature (T) of a gas:
PV = nRT
where R is the gas constant.
To solve for the mass of H2, we need to know the pressure, temperature, and number of moles of the gas. Let's assume that the H2 is at standard temperature and pressure (STP), which is 0 degrees Celsius (273.15 K) and 1 atmosphere of pressure (101.3 kPa).
At STP, 1 mole of any gas occupies 22.4 L of volume. Therefore, the number of moles of H2 in 11.2 L can be calculated as:
n = (11.2 L) / (22.4 L/mol) = 0.5 mol
Now we can use the molar mass of hydrogen (2.016 g/mol) to convert the number of moles to mass:
mass = n x molar mass = 0.5 mol x 2.016 g/mol = 1.008 g
Therefore, the mass of 11.2 L of H2 gas at STP is 1.008 grams.
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Using the "NAS" idea, how many electrons are "needed" for the compound PBr3?
A. 12
B. 32
C. 26
D. 21
Answer:
32
Explanation:
what type of sold materials are typicall hard, have high melting points and poor electrical conductivities
Ionic and covalent network solids are hard, have high melting points, and are poor electrical conductors.
Commonly, materials that are hard, have high liquefying focuses, and poor electrical conductivities are ionic solids or covalent organization solids.
Ionic solids are made out of a three-layered exhibit of emphatically and adversely charged particles kept intact by electrostatic powers. The solid ionic connections between the particles make these solids hard and high softening, while the shortfall of free electrons makes them unfortunate channels of power.
Covalent organization solids, then again, are made out of an immense organization of covalent connections between particles in a gem cross section structure. These covalent bonds are major areas of strength for incredibly, these solids high softening focuses and hardness. Once more, the shortfall of free electrons implies these materials are unfortunate conduits of power.
Instances of ionic solids incorporate NaCl (table salt) and MgO (magnesium oxide), while instances of covalent organization solids incorporate jewel and silicon dioxide (quartz).
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PLEASE HELPPP!! I'M STUCK ON THISS
The arrangement of radial, symmetric, and asymmetric letters is found in the attachment.
What are radial, symmetric, and asymmetric letters?Bilateral Letters: These are letters that have a symmetrical shape where the left and right sides are mirror images of each other. In other words, if you were to draw a vertical line down the center of the letter, both sides would be identical.
Examples of bilateral letters include B, C, D, E, G, H, K, M, O, P, Q, R, S, U, and V.
Radial Letters: These are letters that have a symmetrical or circular shape around a central point. If you were to draw a circle around the letter, it would fit within that circle.
Examples of radial letters include A, C, D, M, and O.
Asymmetric Letters: These are letters that do not have symmetry or balance. If you were to draw a vertical line down the center of the letter, the two sides would not be mirror images of each other.
Examples of asymmetric letters include I, J, L, N, T, U, V, W, X, Y, and Z.
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what is the molecular geometry of the following and would you expect it to have a dipole moment? group of answer choices square planar, no octahedral, yes tetrahedral, yes octahedral, no square planar, yes
The molecular geometry of a given element is octahedral and it has no dipole moment. Therefore octahedral, No would be the correct answer.
The SF6 molecule has no dipole moment because each S−F bond dipole is balanced by one of equal magnitude pointing in the opposite direction of the other side of the molecule.
The three-dimensional configuration of the atoms that make up a molecule is known as molecular geometry. In addition to providing details about the molecule's overall shape, it also provides data on the bond lengths, bond angles, torsional angles, and any other geometrical factors that affect each atom's position.
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Determine the number of moles (n) for 22.5 g of carbon dioxide with a molecular formula of CO₂
There are 0.511 moles of CO 2 in 22.5 gm of the substance
Determine the number of moles of carbon dioxide, we need to use the molecular weight of CO₂ and the given mass of 22.5 g.
The molecular weight of CO₂ is:
c = 12.01 gm/mol
o = 16.00 gm/mol
2 x o = 2 x 16.00 gm/mol = 32.00 gm/mol
So, the molecular weight of CO₂ is 12.01 gm/mol + 32.00 gm/mol = 44.01 gm/mol.
Now, we can use the formula:
no of moles = Given mass / Molar mass
where n is the number of moles, m is the given mass, and M is the molecular weight.
Plugging in the values, we get:
n = 22.5 g / 44.01 g/mol
n = 0.511 moles"
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what mass of oxygen would form from 5 moles of water?
Answer:
Explanation: The equation of water is H2+1/2O2=H2O
->5 moles H2O*1 mol O2/2 mole
-> H2O=2.5 moles O2
->Now, molar mass of O2= 2*16=32gms
To find mass of O2,
-> No. of moles*Molar mass of O2
->2.5*32=0 gms
So, the mass of oxygen will be 80 gms.
Calculate the Heat of Formation for the following reaction.
2NO + O2 ---> 2NO2
The heat of formation of the given reaction is -56.4 kJ/mol.
What is Heat?
Heat is a form of energy that flows from a hotter object to a colder object. It is a type of energy transfer that occurs due to a temperature difference between two objects. The direction of heat flow is always from the object with higher temperature to the object with lower temperature until they reach thermal equilibrium.
The heat of formation of a compound is defined as the enthalpy change when one mole of the compound is formed from its constituent elements in their standard states at a given temperature and pressure. The standard state of an element is its most stable form at 1 atm pressure and a specified temperature.
Using the heat of formation values from standard tables, we can calculate the heat of formation of the products and reactants in the given reaction as follows:
Heat of formation of NO2 = -33.2 kJ/mol
Heat of formation of NO = +90.3 kJ/mol (since NO is an unstable gas at room temperature, we use the heat of formation of NO at 298 K instead of the standard heat of formation)
Heat of formation of O2 = 0 kJ/mol
Therefore, the heat of formation of the given reaction is:
ΔHf = Σ(heat of formation of products) - Σ(heat of formation of reactants)
ΔHf = [2(-33.2 kJ/mol)] - [2(90.3 kJ/mol) + 0 kJ/mol]
ΔHf = -56.4 kJ/mol
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calcium carbonate, also known as limestone, can be heated to produce calcium oxide (lime), an industrial chemical with a wide variety of uses, and carbon dioxide. how many grams of calcium carbonate must be decomposed to produce 5.00 l of carbon dioxide gas at stp?
19.7 g of calcium carbonate must be decomposed to produce 5.00 L of carbon dioxide gas at STP.
Calcium carbonate, also known as limestone, can be heated to produce calcium oxide (lime), an industrial chemical with a wide variety of uses, and carbon dioxide. In order to produce 5.00 L of carbon dioxide gas at STP, we need to determine how many grams of calcium carbonate must be decomposed.The chemical equation for the thermal decomposition of calcium carbonate is:CaCO3 (s) → CaO (s) + CO2 (g).To find out the number of grams of calcium carbonate that must be decomposed to produce 5.00 L of carbon dioxide gas at STP, we can use the following steps:
Step 1: Write down the given information.V = 5.00 L (volume of carbon dioxide gas)T = 273 K (temperature at STP)P = 1 atm (pressure at STP)
Step 2: Use the ideal gas law to calculate the number of moles of carbon dioxide gas.n = PV/RT = (1 atm) x (5.00 L) / (0.0821 L atm/mol K x 273 K) = 0.197 mol
Step 3: Use the stoichiometry of the chemical equation to calculate the number of moles of calcium carbonate required to produce this amount of carbon dioxide gas.
The stoichiometry of the chemical equation tells us that 1 mole of CaCO3 produces 1 mole of CO2. Therefore, we need 0.197 moles of CaCO3 to produce 0.197 moles of CO2.Step 4: Calculate the mass of calcium carbonate required using its molar mass.The molar mass of CaCO3 is 100.1 g/mol. Therefore, the mass of CaCO3 required is:m = n x M = 0.197 mol x 100.1 g/mol = 19.7 g.
Therefore, 19.7g calcium carbonate must be decomposed to produce 5l of co2 gas at STP .
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Methane gas and chlorine gas react to form hydrogen chloride gas and carbon tetrachloride gas. What volume of carbon tetrachloride would be produced by this reaction if 5.0 mL of chlorine were consumed? Also, be sure your answer has a unit symbol, and is rounded to the correct number of significant digits.
Answer:
When 5.0 mL of chlorine gas is consumed, 1.3 mL of carbon tetrachloride gas is produced.
Explanation:
The balanced chemical equation for the reaction between methane gas and chlorine gas is:
CH4(g) + 4Cl2(g) → 4HCl(g) + CCl4(g)
From this equation, we can see that for every 4 moles of chlorine gas that react, 1 mole of carbon tetrachloride is produced.
To determine the volume of carbon tetrachloride produced when 5.0 mL of chlorine gas is consumed, we need to use the ideal gas law. Assuming standard temperature and pressure (STP), which is 0°C and 1 atm, the volume of one mole of any ideal gas is 22.4 L.
First, we need to calculate the number of moles of chlorine gas consumed:
n(Cl2) = V(Cl2) / Vm(Cl2)
n(Cl2) = 5.0 mL / 22.4 L/mol
n(Cl2) = 0.00022321 mol
According to the balanced equation, 4 moles of chlorine gas react to produce 1 mole of carbon tetrachloride. Therefore, the number of moles of carbon tetrachloride produced is:
n(CCl4) = n(Cl2) / 4
n(CCl4) = 0.00022321 mol / 4
n(CCl4) = 5.58025 x 10^-5 mol
Finally, we can calculate the volume of carbon tetrachloride produced using the ideal gas law:
V(CCl4) = n(CCl4) x Vm(CCl4)
V(CCl4) = 5.58025 x 10^-5 mol x 22.4 L/mol
V(CCl4) = 0.001251 L
Rounding to the correct number of significant digits, the volume of carbon tetrachloride produced is 0.0013 L or 1.3 mL.
Therefore, when 5.0 mL of chlorine gas is consumed, 1.3 mL of carbon tetrachloride gas is produced.
8. a second-order reaction has a half-life of 18 s when the initial concentration of reactant is 0.71 m. calculate the rate constant for this reaction
The rates are constant for this reaction 0.0782 M⁻¹s⁻¹. Second-order reactions are those in which the total of the exponents in the appropriate rate law of the chemical reaction equals two.
Second-order reactions are chemical processes that depend on either the concentrations of two first-order reactants or the concentration of one second-order reactant, according to the rate law equations provided below. A chemical reaction's half-life is the length of time it takes for half of the reactant to move through the reaction.
Second-order kinetics can be used to explain a variety of significant biological processes, including the creation of double-stranded DNA from two complementary strands. The total of the exponents in the rate law is equal to two in a second-order reaction. In this section, the two most typical types of second-order reactions will be thoroughly covered.
The differential (derivative) rate equation and the integrated rate equation are used to explain how the rate of a second-order reaction varies with the concentration of reactants or products. The integrated rate equation demonstrates how the concentration of species varies over time, whereas the differential rate law demonstrates how the reaction's rate changes over time.
Second order reaction for calculating rate constant is
t1/2 = 1/KCAO
Half-Life period = 18 s
Initial Concentration of reactant = 0.71M
18s = 1/K(0.71M)
K = 0.0782 M⁻¹s⁻¹
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