Hydrogen gas and oxygen gas are produced at the cathode and anode, respectively when a solution of Na₂SO4 containing several drops of phenolphthalein is electrolyzed between Pt electrodes.
When a solution of Na₂SO4 containing several drops of phenolphthalein is electrolyzed between Pt electrodes, the following reaction takes place:
2H₂O(l) + 2e- ⟶ H₂(g) + 2OH⁻(aq)
Na₂SO4 (solute) dissociates into ions, i.e., Na+ and SO₄²⁻ in the solution.
When the current is passed through this solution, the positively charged sodium ions migrate towards the negative electrode, i.e., the cathode, whereas the negatively charged sulfate ions migrate towards the positive electrode, i.e., the anode.
At the cathode, the hydrogen ion accepts electrons from the cathode and reduces to hydrogen gas. At the anode, the sulfate ion releases electrons to the anode and oxidizes to form oxygen gas.
The following are the balanced equations for these reactions:
2H⁺(aq) + 2e⁻ ⟶ H₂(g)
SO₄²⁻(aq) ⟶ O₂(g) + 4e⁻
Phenolphthalein is a pH indicator, and its color changes from colorless to pink as the pH increases above 8.2. When Na₂SO4 containing several drops of phenolphthalein is electrolyzed between Pt electrodes, the solution initially turns pink at the anode because OH⁻ ions are produced in excess, which increases the pH beyond 8.2.
However, at the cathode, the concentration of OH⁻ ions decreases as they react with the H+ ions to form water molecules. As a result, the solution around the cathode becomes acidic, and the pink color of phenolphthalein fades away.
Therefore, when a solution of Na₂SO4 containing several drops of phenolphthalein is electrolyzed between Pt electrodes, hydrogen gas, and oxygen gas are produced at the cathode and anode, respectively. The pink color of phenolphthalein fades away at the cathode due to the decrease in OH- concentration.
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if you add 25 ml of water to 15 ml of a 0.050 m hcl solution, what is the new concentration of the solution?
The initial volume of the solution is 15 mL, and when 25 mL of water is added, the new volume of the solution is 40 mL. Therefore, the new concentration of the solution is 0.01875 M.
The initial concentration of the solution is 0.050 M, and since the volume of the solution increased to 40 mL, the new concentration of the solution will be (0.050 M) * (15 mL/40 mL) = 0.01875 M.
To determine the new concentration of a solution after the addition of a specified volume of solvent, use the dilution equation.
The equation for dilution is: C1V1 = C2V2, where C1 is the initial concentration of the solution, V1 is the initial volume of the solution, C2 is the final concentration of the solution and V2 is the final volume of the solution.
Given that:
Initial concentration of HCl solution, C1 = 0.050 M
Initial volume of HCl solution, V1 = 15 mL
Volume of water added, V = 25 mL
Let's find out the final volume of the solution by adding the initial volume to the volume of water added.V2 = V1 + V2 = 15 mL + 25 mL = 40 mL.
Let's substitute the known values in the dilution equation and solve for the final concentration of the solution.
C1V1 = C2V2
0.050 M × 15 mL = C2 × 40 mL
0.750 = 40 × C2
C2 = 0.750/40
C2 = 0.01875M
The final concentration of the HCl solution after the addition of 25 mL of water is 0.01875 M.
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explain why only one peak is present (either the anodic or cathodic peak) in a cyclic voltammogram of an irreversible electrochemical reaction.
In a cyclic voltammogram of an irreversible electrochemical reaction, only one peak is present (either anodic or cathodic) due to the limited reversibility of the reaction.
An irreversible reaction cannot be completely reversed so when the potential of the reaction is increased, the reaction will proceed in the same direction, leading to the formation of a single peak.
The peak represents the forward reaction, either the oxidation or reduction of the species in the reaction.
The magnitude of the peak depends on the rate of the forward reaction and the degree of reversibility of the reaction.
When the potential of the reaction is increased, the reaction will move further in the same direction, and the peak will become more prominent.
The peak will reach a maximum size when the reaction reaches its equilibrium potential, which occurs when the rate of the forward and reverse reactions are equal.
The magnitude of the peak also depends on the rate of diffusion of the species in the reaction. The peak will be smaller when the rate of diffusion is slow, and it will be larger when the rate of diffusion is fast.
The shape of the peak will depend on the degree of reversibility of the reaction, with more symmetrical peaks for reversible reactions and more asymmetrical peaks for irreversible reactions.
Only one peak is present in a cyclic voltammogram of an irreversible electrochemical reaction due to the limited reversibility of the reaction.
The magnitude of the peak is determined by the rate of the forward reaction, the rate of diffusion of the species, and the degree of reversibility of the reaction.
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is it possible to determine the amount of energy released in a in a combustion reaction, the energy released as the products form is
The negative value of the heat of reaction indicates that the combustion of methane is an exothermic reaction, and 890.3 kJ of heat are released per mole of methane burned.
Is it possible to determine the amount of energy released in combustion reaction?Yes, it is possible to determine the amount of energy released in a combustion reaction. Energy released as the products form is called the heat of reaction or enthalpy change (ΔHrxn) and can be calculated using balanced chemical equation and the standard enthalpies of formation (ΔHf) of reactants and products.
The standard enthalpy of formation of an element in its standard state is defined as zero.
ΔHrxn = ΣnΔHf(products) - ΣmΔHf(reactants)
ΔHf(products) is the standard enthalpy of formation of each product, n is the stoichiometric coefficient of each product, ΔHf(reactants) is standard enthalpy of formation of each reactant, and m is the stoichiometric coefficient of each reactant.
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
The standard enthalpies of formation of methane, oxygen, carbon dioxide, and water are -74.8 kJ/mol, 0 kJ/mol, -393.5 kJ/mol, and -285.8 kJ/mol, respectively.
ΔHrxn = [ΔHf(CO2) + 2ΔHf(H2O)] - [ΔHf(CH4) + 2ΔHf(O2)]
= [(-393.5 kJ/mol) + 2(-285.8 kJ/mol)] - [(-74.8 kJ/mol) + 2(0 kJ/mol)]
= -890.3 kJ/mol
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At what temperature will 0.505 mole of CO2 occupy a volume of 3.50 x 103 mL at a pressure of 3185 mmHg?
Answer:
3.5 x 10^3 ml
Explanation:
We can use the ideal gas law to solve this problem:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
First, we need to convert the volume to liters and the pressure to atmospheres:
V = 3.50 x 10^-3 L
P = 3185 mmHg / 760 mmHg/atm = 4.19 atm
Next, we can solve for T:
T = PV / nR
T = (4.19 atm) (0.505 mol) (0.08206 L atm mol^-1 K^-1) / (3.50 x 10^-3 L)
T = 1074 K
Therefore, at a temperature of 1074 K (801°C or 1474°F), 0.505 mole of CO2 will occupy a volume of 3.50 x 10^3 ml at a pressure of 3185 mmHg.
when a 25.7 ml sample of a 0.494 m aqueous hydrofluoric acid solution is titrated with a 0.424 m aqueous sodium hydroxide solution, what is the ph after 44.9 ml of sodium hydroxide have been added?
When a 25.7 mL sample of a 0.494 M aqueous hydrofluoric acid solution is titrated with a 0.424 M aqueous sodium hydroxide solution, the pH after 44.9 mL of sodium hydroxide have been added is 8.71.
When a 25.7 mL sample of a 0.494 M aqueous hydrofluoric acid solution is titrated with a 0.424 M aqueous sodium hydroxide solution, the pH after 44.9 mL of sodium hydroxide have been added can be calculated using the Henderson-Hasselbalch equation. This equation states that the pH of a solution is equal to the pKa (the acid dissociation constant) plus the logarithm of the base-to-acid ratio. The pKa of hydrofluoric acid is 3.2 and the base-to-acid ratio is the molarity of the sodium hydroxide (0.424 M) divided by the molarity of the hydrofluoric acid (0.494 M). This gives a ratio of 0.855 and a pH of 7.12.
To calculate the pH of the solution after 44.9 mL of sodium hydroxide have been added, the volume of hydrofluoric acid solution added must be taken into account. Since 25.7 mL of the hydrofluoric acid solution was initially present, an additional 19.2 mL of sodium hydroxide must be added. Using the Henderson-Hasselbalch equation, this gives a base-to-acid ratio of 1.608 and a pH of 8.71.
In summary, when a 25.7 mL sample of a 0.494 M aqueous hydrofluoric acid solution is titrated with a 0.424 M aqueous sodium hydroxide solution, the pH after 44.9 mL of sodium hydroxide have been added is 8.71. This is calculated using the Henderson-Hasselbalch equation and taking into account the additional volume of sodium hydroxide added.
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a tertiary alkyl bromide was heated in ethanol, thereby giving both sn1 and e1 reaction products. which statement is false concerning the sn1 and e1 reactions that occur?select answer from the options belowthe rate determining step for both processes is the first step: loss of the leaving group.in the sn1 mechanism, the solvent (ethanol) serves as the nucleophile, whereas in the e1 mechanism, the solvent serves as the base.the sn1 and e1 reaction mechanisms both involve a carbocation intermediate.the sn1 and e1 reaction mechanisms are both concerted processes.
the sn1 and e1 reaction mechanisms are both concerted processes is false concerning the sn1 and e1 reactions that occur
Which reaction conditions are favourable to SN1 and E1?In general, the necessary carbocation intermediate must be somewhat stable in order for an SN1 or E1 reaction to occur. Strong nucleophiles prefer substitution, while strong bases, particularly strong hindered bases (such as tert-butoxide), prefer elimination.
Both E1 and SN1 start the same, with the dissociation of a leaving group, generating a trigonal planar molecule containing a carbocation. This molecule is then attacked by a nucleophile in the case of SN1 or by a base in the case of E1.
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Use Hess' Law to calculate the change in enthalpy in the combustion of ethanol.
Combustion has a constant enthalpy, Hc. The heat produced when 1 mol of a material burns fully in oxygen under typical conditions.
Hess' lawThe total enthalpy change for a reaction is equal to the sum of all changes, according to Hess's Law of Constant Heat Summation (also known as Hess's Law). Enthalpy's role as a state function is demonstrated by this law.An illustration might be C2H2(g)+52O2(g)2CO2(g)+H2O. (l)Using common enthalpies of formation, you compute Hc:p denotes "products," and r denotes "reactants," in the formula H°c=Hf(p)Hf(r).You divide the coefficient in the balanced equation by the product's Hf for each product, then add the results.Reactants should be treated similarly. Add the product sum and subtract the reactant sum. C2H2(g)+52O2(g)→2CO2(g)+H2O(l)ΔH°c=∑ΔH∘f(p)−∑ΔH∘f(r)[2 × (-393.5) + (-295.8)] – [226.7 + 0] kJ\s=-1082.8 - 226.7\s=-1309.5 kJ.Acetylene has a combustion heat of -1309.5 kJ/mol.For more information on Hess' law kindly visit to
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what is the specific rotation of pure (s)-carvone if a sample of (r)-carvone of 85% ee has a specific rotation of -52?
(+61.3) is the specific rotation of pure (s)-carvone if a sample of (r)-carvone of 85% ee has a specific rotation of -52.
A chiral chemical compound's unique rotation is a characteristic in chemistry. It is described as the shift in monochromatic plane-polarized light's orientation, expressed as the product of distance and concentration, as the light passes through a sample of a substance dissolved in solution. Dextrorotary substances are those that spin a plane polarised light beam's polarisation plane clockwise, and they correlate to positive specific rotation values.
[α] = α / (c×l)
[α] =specific rotation
α = observed rotation
c=concentration in g/mL
l =path length in dm
[α] = (-52)/(1×1)
= -52
(-52) = (0.85)×αr + (0.15)×αs
αs= (-52 - 0.85×αr) / 0.15
[α] = αs
= (-52 - 0.85αr) / 0.15
(-52) = (0.85)(+112.0) + (0.15)α
α = (+61.3)
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4. a laboratory experiment calls for 0.150 m hno3. what volume of 0.150 m hno3 can be prepared form 0.350 l of 1.98 m hno3?
The volume of 0.150 M HNO3 that can be prepared from 0.350 L of 1.98 M HNO3 is 0.07112 L, or approximately 71.12 mL (since 1 L = 1000 mL).
The given equation is used to calculate the volume (V1) of a desired concentration of a solution (0.150 M HNO3) that can be prepared from a given volume (V2) of a known concentration solution (1.98 M HNO3), using the ratios of their concentrations (C1 and C2).
Let's break down the calculation step by step using the given values:
V2 (given volume) = 0.350 L
C1 (desired concentration) = 0.150 M
C2 (known concentration) = 1.98 M
Plugging these values into the equation, we get:
V1 (0.150 M HNO3) = V2 (1.98 M HNO3) x (C1 (0.150 M) / C2 (1.98 M))
V1 = 0.350 L x (0.150 M / 1.98 M)
V1 = 0.350 L x 0.0758
V1 = 0.07112 L
Therefore, the volume of 0.150 M HNO3 that can be prepared from 0.350 L of 1.98 M HNO3 is 0.07112 L, or approximately 71.12 mL (since 1 L = 1000 mL).
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what's the difference between an alkane and an alkene?? simple answer pls
Answer:
Alkanes have only single bonds between carbon atoms. Alkenes have at least one carbon-carbon double bond. When trying to determine which is which in a lab setting, you can use bromine water. When mixed with an alkane, it will remain orange, but when mixed with an alkene, it turns colorless.
9) if you had a stock of 100% ethanol and wanted to make 250ml of a 70% ethanol solution (in water), how would you make it?
To make a 250 ml solution of 70% ethanol, you will need 175 ml of ethanol and 75 ml of water. The solution will have a final volume of 250 ml with a 70% ethanol concentration.
To make 250 ml of a 70% ethanol solution (in water) from a stock of 100% ethanol, you will need to take the following steps:
Step 1:
Calculate the amount of ethanol required for the solution. The volume of ethanol required to make 250 ml of a 70% ethanol solution can be calculated as follows:
Volume of ethanol = (70/100) x 250 ml= 175 ml
So, you will need 175 ml of 100% ethanol to make a 250 ml solution with a 70% ethanol concentration.
Step 2:
Calculate the volume of water required. To calculate the volume of water needed, subtract the volume of ethanol from the total volume of the solution.
Volume of water = Total volume of solution – Volume of ethanol
= 250 ml – 175 ml= 75 ml
Therefore, you will need 75 ml of water.
Step 3:
Mix the ethanol and water together in the right proportion. Once you have calculated the amount of ethanol and water required, add the 175 ml of ethanol to the 75 ml of water to obtain the 250 ml solution of 70% ethanol in water.
Consequently, the solution will have a final volume of 250 ml with a 70% ethanol concentration.
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at what temperature is the system at equilibrium? at what temperature is the system at equilibrium? t>250k t<250k t
If the value of ΔG° is equal to 0, then the value of K or Kp is equal to 1 and the system is said to be in equilibrium.
A change in temperature occurs when heat flow increases or decreases the temperature. This changes the chemical equilibrium towards the products or the reactants. This can be identified by examining the reaction and determining whether it is an endothermic reaction or an exothermic reaction.
If the temperature is raised, the equilibrium constant decreases. If the forward reaction has an endothermic nature, the equilibrium constant increases. The equilibrium position also changes when the temperature is changed.
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determine the limiting reagent in the reaction between 1,6-diaminohexane and sebacoyl chloride. calculate the percent yield of nylon using the molecular weight of one repeating monomer unit for the weight of the product.
The limiting reagent is sebacoyl chloride because we have fewer moles of it than 1,6-diamino hexane.
What is the limiting reagent?The reaction between 1,6-diamino hexane and sebacoyl chloride forms nylon-6,10, and the balanced chemical equation for the reaction is:
1,6-diaminohexane + sebacoyl chloride → nylon-6,10 + 2 HCl
To determine the limiting reagent, we need to compare the moles of each reactant to the stoichiometric ratio in the balanced equation.
Let's assume we have 2.00 moles of 1,6-diaminohexane and 1.50 moles of sebacoyl chloride.
The stoichiometric ratio in the balanced equation is 1:1, so we need an equal number of moles of both reactants to form nylon-6,10.
From the given amounts, we can calculate the moles of each reactant:
moles of 1,6-diaminohexane = 2.00 moles
moles of sebacoyl chloride = 1.50 moles
Since the stoichiometric ratio is 1:1, the limiting reagent is sebacoyl chloride because we have fewer moles of it than 1,6-diaminohexane.
To calculate the percent yield of nylon, we need to know the mass of the product formed. We can use the molecular weight of one repeating monomer unit of nylon-6,10 to calculate the weight of the product.
The molecular weight of one repeating monomer unit of nylon-6,10 is:
molecular weight of 1,6-diaminohexane: 116.20 g/mol
molecular weight of sebacoyl chloride: 260.41 g/mol
molecular weight of one repeating monomer unit: 226.61 g/mol (116.20 + 260.41 - 2*36.46)
To calculate the theoretical yield of nylon, we need to use the stoichiometric ratio and the amount of limiting reagent. Since the limiting reagent is sebacoyl chloride, we will use its moles to calculate the theoretical yield of nylon:
moles of sebacoyl chloride = 1.50 moles
moles of nylon-6,10 = 1.50 moles (from stoichiometric ratio)
The mass of the theoretical yield of nylon-6,10 is:
mass of nylon-6,10 = moles of nylon-6,10 x molecular weight of nylon-6,10
mass of nylon-6,10 = 1.50 moles x 226.61 g/mol = 339.92 g
Assuming that the actual yield of nylon-6,10 is 280.00 g, the percent yield is:
percent yield = (actual yield / theoretical yield) x 100%
percent yield = (280.00 g / 339.92 g) x 100%
percent yield = 82.36%
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Complete question:
what is the limiting reagent in the reaction between 1,6-diaminohexane and sebacoyl chloride. calculate the percent yield of nylon using molecular weight of one repeating monomer unit for the weight of the product
actual yield for nylon : 280.00 g
Another method of reporting the hardness of water is in grains per gallon. Take one grain to be 17. 14 ppm of calcium carbonate. What is the hardness of the unknown sample you analyzed reported in grains per gallon?
To convert from parts per million (ppm) of calcium carbonate to grains per gallon (GPG), we use the following formula:
Hardness in GPG = Hardness in ppm / 17.14
Since we do not have the hardness in ppm, we cannot directly convert to GPG. We need more information or data to calculate the hardness in GPG.
Without the ppm of calcium carbonate, we cannot determine the hardness in grains per gallon.
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When the reaction below produces 11.6 g of ethylene, C₂H4 it produces 2.4 L of hydrogen
gas at 300 K. What is the pressure of the hydrogen gas?
2 CH4 -> C₂H4 + 2 H₂
Answer:
8.35 atm.
Explanation:
The given reaction is:
2 CH4 → C2H4 + 2 H2
From the balanced equation, we can see that for every mole of C2H4 produced, 2 moles of H2 are produced.
First, we need to find the number of moles of C2H4 produced:
Molar mass of C2H4 = 2(12.01 g/mol) + 4(1.01 g/mol) = 28.05 g/mol
Number of moles of C2H4 = 11.6 g / 28.05 g/mol = 0.413 mol
Since 2 moles of H2 are produced for every mole of C2H4, the number of moles of H2 produced is:
0.413 mol C2H4 × 2 mol H2 / 1 mol C2H4 = 0.826 mol H2
Now we can use the ideal gas law to find the pressure of H2:
PV = nRT
where P is pressure, V is volume, n is the number of moles, R is the gas constant (0.0821 L·atm/K·mol), and T is temperature in Kelvin.
We are given the volume (2.4 L) and temperature (300 K), and we just calculated the number of moles (0.826 mol). Plugging these values into the ideal gas law:
P × 2.4 L = 0.826 mol × 0.0821 L·atm/K·mol × 300 K
P = (0.826 mol × 0.0821 L·atm/K·mol × 300 K) / 2.4 L
P = 8.35 atm
Therefore, the pressure of hydrogen gas is 8.35 atm.
the radioactive decay of c14 which is used in estimating the age of archaeological samples follows first order kinetics with a half-life of 5725 years at 300k. if a sample of c114 initially contains 0.0035 mol of c14, how many moles remain after 2500 years.
the radioactive decay of c14 which is used in estimating the age of archaeological after 2500 years, 0.0027 mol of c14 remain in the sample.
The amount of c14 remaining after 2500 years can be calculated using the first-order rate equation:
N(t) = N0 * e^(-kt)
where N0 is the initial amount of c14, N(t) is the amount remaining after time t, k is the decay constant, and e is the base of the natural logarithm. The half-life of c14 is given as 5725 years, which means that k can be calculated as:
k = ln(2)/t1/2 = ln(2)/5725
Substituting the values given in the problem, we get:
k = ln(2)/5725 = 1.21 * 10^-4 /year
Now, we can use the rate equation to find the amount of c14 remaining after 2500 years:
N(2500) = 0.0035 * e^(-1.21*10^-4 * 2500) = 0.0027 mol
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what is the term for the shorthand description of the arrangement of electrons by sublevels according to increasing energy? group of answer choices atomic notation atomic number continuous spectrum electron configuration none of the above
The term for the shorthand description of the arrangement of electrons by sublevels according to increasing energy is electron configuration.
This means that electrons are arranged in the atom in the order of increasing energy. The order follows the patterns of the periodic table and consists of the following components:
Principal Quantum Number (n): This is the overall energy level of the electron. It determines how far away from the nucleus the electron is located.Azimuthal Quantum Number (l): This is a measure of the angular momentum of the electron. It describes the type of orbital the electron occupies, such as s, p, d, or f.Magnetic Quantum Number (m): This number describes the orientation of the orbital in space.Spin Quantum Number (s): This is the spin of the electron, which can be either clockwise (spin-up) or counterclockwise (spin-down).
These components are usually written in shorthand notation, with the principal quantum number first, followed by a letter for the azimuthal quantum number, and then a number for the magnetic quantum number. For example, the shorthand for the electron configuration of hydrogen is 1s1, where 1 is the principal quantum number, s is the azimuthal quantum number, and 1 is the magnetic quantum number.
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if a plant produces 4.91 mol c6h12o6, 4.91 mol c 6 h 12 o 6 , how many moles of co2 co 2 are needed?
Answer: If a plant produces 4.91 mol C6H12O6, then 6 x 4.91 = 29.46 moles of O2 are needed to produce 4.91 mol C6H12O6.
However, there is no given reaction, so it is not clear how O2 is involved. The balanced reaction equation for cellular respiration is:
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP)
The ratio of CO2 to C6H12O6 is 6:1, which means 6 moles of CO2 is produced from every mole of C6H12O6 in the reaction. The ratio of O2 to C6H12O6 is 6:1 as well.
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a chemist mixes of water with of methanol and of 2-methylpyrazine. calculate the percent by mass of each component of this solution. be sure each of your answer entries has the correct number of significant digits.
The percent by mass of each component of the solution is water: 35.5%, 2-methylpyrazine: 32.73%, and methanol: 31.82%, rounded to 2 significant digits.
The percentage by mass of each component of a solution containing 39. g of water, 36. g of 2-methylpyrazine, and 35. g of methanol can be calculated as follows:
Mass of water = 39. g
Mass of 2-methylpyrazine = 36. g
Mass of methanol = 35. g
Total mass of solution = (39. g + 36. g + 35. g) = 110. g
Percentage by mass of water = (Mass of water/Total mass of solution) × 100= (39. g/110. g) × 100= 35.45% (rounded to 2 significant digits)
Percentage by mass of 2-methylpyrazine = (Mass of 2-methylpyrazine/Total mass of solution) × 100= (36. g/110. g) × 100= 32.73% (rounded to 2 significant digits)
Percentage by mass of methanol = (Mass of methanol/Total mass of solution) × 100= (35. g/110. g) × 100 = 31.82% (rounded to 2 significant digits)
Therefore, the percentage by mass of water is 35.45%, the percentage by mass of 2-methylpyrazine is 32.73%, and the percentage by mass of methanol is 31.82%.
The question you wrote is incomplete, maybe the complete question is:
chemist mixes 39. g of water with 36. g of 2-methylpyrazine and 35. g of methanol. Calculate the percent by mass of each component of this solution. Round each of your answers to 2 significant digits component mass percent.
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cobalt(ii) chloride is dissolved in ethanol, and then water is added. what is the co(ii) complex equilibrium reaction? equilibrium reaction:
The equilibrium reaction for the formation of cobalt(II) complex when cobalt(II) chloride is dissolved in ethanol and then water is added is given by the following equation:
CoC₂l + 4 ethanol → Co(C₂H₅OH)₄Cl₂
When the cobalt(II) chloride is dissolved in ethanol, a cobalt(II) complex is formed. The complex is a tetrahedral molecule with four ethanol molecules attached to the cobalt ion. When water is added, it causes the equilibrium reaction to shifting to the right, with more of the cobalt(II) complex being formed. This is because the water molecules can displace the ethanol molecules from the complex, allowing the complex to form. The reaction can be expressed as:
CoC₂H₅OH)₄Cl₂ + 4 H₂O ↔ Co(H₂O)₄Cl₂ + 4 C₂H₅OH
In conclusion, the equilibrium reaction for the formation of cobalt(II) complex when cobalt(II) chloride is dissolved in ethanol and then water is added can be given as:
CoCl₂ + 4 ethanol → Co(C₂H₅OH)₄Cl₂ + 4 H₂O ↔ Co(H₂O)₄Cl₂ + 4 C₂H₅OH.
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describe how you can determine the ratio of cis- and trans-2-methylcyclohexanols from the 1h nmr spectrum provided. (hint: what do the peaks at 3.05 ppm and 3.75 ppm represent and what does their integration show?)
The ratio of cis-2-methylcyclohexanol to trans-2-methylcyclohexanol can be determined from the 1H NMR spectrum by analyzing the chemical shift and integration of the two peaks present.
In order to determine the ratio of cis- and trans-2-methylcyclohexanols from the 1H NMR spectrum provided, one must interpret the chemical shift and integration of the various peaks present.What is 1H NMR spectroscopy?1H NMR spectroscopy, also known as proton NMR spectroscopy or magnetic resonance spectroscopy, is a technique used to determine the molecular structure of a sample by analyzing its nuclear magnetic resonance (NMR) properties. The chemical shift and integration of a molecule's protons can be used to identify the molecule's structure and determine its ratio of cis- and trans-2-methylcyclohexanols.Here are the steps to determine the ratio of cis- and trans-2-methylcyclohexanols from the 1H NMR spectrum provided:Identify the peaks: In this case, there are two peaks present in the spectrum at 3.05 ppm and 3.75 ppm. These peaks correspond to the protons present in the 2-methylcyclohexanol molecule.3.05 ppm peak: This peak corresponds to the proton present in the trans-2-methylcyclohexanol molecule.3.75 ppm peak: This peak corresponds to the proton present in the cis-2-methylcyclohexanol molecule.Integration: Integration is the measurement of the relative abundance of each type of proton present in the sample. In this case, the ratio of the two peaks can be used to determine the ratio of cis- and trans-2-methylcyclohexanols.Using the integration values of the peaks, the ratio of cis-2-methylcyclohexanol to trans-2-methylcyclohexanol can be calculated. If there are two integrals with a 1:1 ratio, there is an equal amount of cis- and trans-2-methylcyclohexanols present in the sample. If the ratio is 2:1 or 1:2, there are twice as many molecules of one isomer present as the other isomer.Explain in 200 words about how you can determine the ratio of cis- and trans-2-methylcyclohexanols from the 1H NMR spectrum provided1H NMR spectroscopy is a type of nuclear magnetic resonance spectroscopy that can be used to analyze the structure of a molecule. The chemical shift and integration of the protons in a molecule can provide valuable information about its composition and structure.In the case of the 1H NMR spectrum provided, there are two peaks present at 3.05 ppm and 3.75 ppm. These peaks correspond to the protons present in the 2-methylcyclohexanol molecule. The 3.05 ppm peak corresponds to the trans-2-methylcyclohexanol molecule, while the 3.75 ppm peak corresponds to the cis-2-methylcyclohexanol molecule.Integration is the measurement of the relative abundance of each type of proton present in the sample. In this case, the ratio of cis-2-methylcyclohexanol to trans-2-methylcyclohexanol can be calculated using the integration values of the peaks.If there are two integrals with a 1:1 ratio, there is an equal amount of cis- and trans-2-methylcyclohexanols present in the sample. If the ratio is 2:1 or 1:2, there are twice as many molecules of one isomer present as the other isomer. Therefore, the ratio of cis-2-methylcyclohexanol to trans-2-methylcyclohexanol can be determined from the 1H NMR spectrum by analyzing the chemical shift and integration of the two peaks present.
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What is the heat, q , in joules transferred by a chemical reaction to the reservoir of a calorimeter containing 155 g of dilute aqueous solution ( c = 4.184 J/g⋅K ) if the reaction causes the temperature of the reservoir to rise from 22.0 ºC to 26.5 ºC ?
To calculate the heat transferred by the chemical reaction, we can use the equation:
q = mcΔT
where q is the heat transferred, m is the mass of the solution, c is the specific heat capacity of the solution, and ΔT is the change in temperature.
Given:
m = 155 g
c = 4.184 J/g⋅K
ΔT = 26.5 ºC - 22.0 ºC = 4.5 ºC
Substituting these values into the equation, we get:
q = (155 g) x (4.184 J/g⋅K) x (4.5 ºC)
q = 29168.98 J or approximately 29.2 kJ
Therefore, the heat transferred by the chemical reaction to the calorimeter reservoir is 29.2 kJ.
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g cyclohexane and 2 hexene have the same molecular formula what chemical test would you carry out to distinguish the two compounds provide a chemical equation for the reaction
To distinguish between cyclohexane and 2-hexene, you can carry out the bromine water test. Chemical equation for the reaction is 2-hexene + Br2 (aq) -> 2,3-dibromohexane
This test is based on the fact that cyclohexane is an alkane and 2-hexene is an alkene. Alkenes readily react with bromine water due to the presence of a double bond, while alkanes do not react.
Add a few drops of bromine water to separate test tubes containing cyclohexane and 2-hexene.
Observe the color change in the test tubes.
Chemical equation for the reaction:
2-hexene + Br2 (aq) -> 2,3-dibromohexane
Upon reaction, the bromine water loses its color in the presence of 2-hexene, while it remains the same in the presence of cyclohexane.
This difference in color change will help you distinguish between the two compounds.
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lindane (hexachlorocyclohexane) is an agricultural insecticide that can also be used in the treatment of head lice. which is the lowest energy chair conformation of lindane?
Lindane (hexachlorocyclohexane) is an agricultural insecticide that can also be used to treat head lice. The lowest energy chair conformation of lindane is a slightly puckered chair conformation, which is a six-membered ring of alternating single and double bonds. The hydrogen atoms are positioned in an axial orientation and the chlorine atoms are in an axial orientation.
Lindane (hexachlorocyclohexane) is an agricultural insecticide that can also be used in the treatment of head lice. The lowest energy chair conformation of lindane isThe lowest energy chair conformation of lindane is the one with the Cl atom and the H atom in equatorial positions. The molecule of lindane consists of six carbon atoms joined together in the form of a ring.Each carbon atom is attached to one hydrogen atom and one chlorine atom. The relative orientations of the C-H and C-Cl bonds determine the conformation of the molecule. The ring can assume various conformations, and the lowest energy conformation is the most stable. The conformation of the molecule can be analyzed by assigning axial and equatorial positions to the atoms on the carbon ring. In the axial position, the atoms are oriented perpendicular to the ring. In the equatorial position, the atoms are oriented at an angle of 120° with respect to the ring. The axial orientation is less stable than the equatorial orientation because the axial atoms experience steric hindrance from the other atoms on the ring. The steric hindrance is reduced in the equatorial orientation, and this results in a lower energy conformation. Thus, the lowest energy chair conformation of lindane is the one with the Cl atom and the H atom in equatorial positions.
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calculate the ph of a buffer solution that is formed by mixing 85 ml of 0.13 m lactic acid with 95 ml of 0.14 sodium lactate
The pH of a buffer solution that is formed by mixing 85 ml of 0.13 M lactic acid with 95 ml of 0.14 M sodium lactate is 4.91.
What is a buffer solution?A buffer solution is an aqueous solution that can resist changes in pH even when small quantities of acidic or basic substances are added to it. Buffers have the ability to maintain their pH in the presence of an acid or base. This is due to the presence of conjugate acid-base pairs in the buffer solution.
Calculation:Given:Initial concentration of lactic acid = 0.13 MInitial concentration of sodium lactate = 0.14 MVolume of lactic acid = 85 mlVolume of sodium lactate = 95 mlpKa of lactic acid = 3.86The Henderson-Hasselbalch equation for pH is:pH = pKa + log [A-]/[HA]where pKa is the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid.In this problem, lactic acid (HA) is the acid and sodium lactate (A-) is the conjugate base.
We must first calculate the concentrations of the acid and its conjugate base.[HA] = 0.13 M x 85/180 ml = 0.0611 M[A-] = 0.14 M x 95/180 ml = 0.0737 M, Substitute the values of [A-], [HA] and pKa in the above equation, we get:pH = 3.86 + log (0.0737/0.0611)pH = 4.91Hence, the pH of the buffer solution is 4.91.
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what is the ph of a solution that is prepared by mixing 100 ml of 0.20 m hcl with 200 ml of 0.10 m naoh
Answer: The pH of the solution is 1.44.
Explanation:
The given solution is a mixture of 100 mL of 0.20 M HCl and 200 mL of 0.10 M NaOH. Since NaCl is a neutral salt, it does not contribute to the concentration of H+ or OH-. The concentration of OH- can be calculated from the concentration of NaOH that was added, which is 0 M. Substituting the concentration of OH- into the equation for [H+], [H+] is found to be infinity which is not physically possible. Therefore, the pH of the solution is calculated using the equation pH = -log[H+], which gives a value of 1.44.
what volume (ml) of 7.48x10-2 m perchloric acid can be neutralized with 115ml of 0.244m sodium hydroxide?
The volume of 0.375 mL of 7.48x10-2 m perchloric acid can be neutralized with 115ml of 0.244m sodium hydroxide
To solve this problem, we need to calculate the number of moles of each substance first. For 7.48x10-2 m perchloric acid, the number of moles can be calculated using the molarity and the volume:
Moles of Perchloric Acid = (7.48x10-2 m) x (115 mL) = 0.00864 mol
To calculate the number of moles of sodium hydroxide, we can use the same method:
Moles of Sodium Hydroxide = (0.244 m) x (115 mL) = 0.0281 mol
Since both the perchloric acid and sodium hydroxide are in equal molar ratios, we know that 0.00864 mol of perchloric acid will be neutralized by 0.0281 mol of sodium hydroxide. To calculate the volume of the perchloric acid needed for this reaction, we can use the following equation:
Volume (mL) of Perchloric Acid = (0.0281 mol) / (7.48x10-2 m) = 0.375 mL
Therefore, 0.375 mL of 7.48x10-2 m perchloric acid can be neutralized with 115 mL of 0.244m sodium hydroxide.
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benzene has bp of 80oc, toluene has bp of 110 oc and xylene has boiling point of 130 oc. the gc of a mixture of these three compounds should show retention times as
Answer: Benzene has a boiling point of 80oC, toluene has a boiling point of 110 oC, and xylene has a boiling point of 130 oC. The GC of a mixture of these three compounds should show retention times as benzene, toluene, xylene.
The GC of a mixture of these three compounds should show retention times as. The correct answer is Option C; benzene, toluene, xylene. The boiling points of the components indicate that they have different volatility.
Therefore, the order of volatility follows the order in which they have been mentioned in the question;
benzene < toluene < xylene
This means that as the boiling point increases, the retention time of each compound in the column also increases. Since the order of volatility is benzene < toluene < xylene, the retention times of the compounds will be as follows; benzene will have the least retention time, followed by toluene and then xylene, with the largest retention time.
Therefore, the GC of a mixture of these three compounds should show retention times as benzene, toluene, and xylene.
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of the five chemical types of recyclable plastics listed in the lab manual document, which should give the simplest infrared spectrum, and why?
The chemical type of recyclable plastics that should give the simplest infrared spectrum is Polyethylene Terephthalate (PET). This is because PET has fewer functional groups, which reduces the number of peaks in the infrared spectrum.
What is infrared spectroscopy?Infrared spectroscopy is a technique used to determine the presence and concentration of various compounds based on the way they absorb infrared radiation. When molecules absorb infrared radiation, the bonds between atoms within the molecule vibrate at different frequencies, resulting in a unique infrared spectrum.
The plastic industry employs infrared spectroscopy to detect and analyze various polymer structures. The most common types of plastics are recyclable, with each plastic having its own unique chemical composition and, as a result, an infrared spectrum. Infrared spectroscopy is a powerful tool for studying these different plastic types.
According to the lab manual document, there are five chemical types of recyclable plastics, and each plastic type gives an infrared spectrum with its unique functional group peaks. The chemical types of recyclable plastics are Polyethylene Terephthalate (PET), High-density polyethene (HDPE), Polyvinyl Chloride (PVC), Low-density polyethene (LDPE) and Polypropylene (PP).
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now you will investigate the emission spectra for a different element, helium. helium is the next element after hydrogen on the periodic table and has two electrons. do you think the emission spectra for an atom with two electrons instead of one will be significantly different than that of hydrogen? explain your answer.
The electron configuration of Helium (He) is 1s², which means that it has two electrons in its outermost shell.
Helium is an inert gas and, like hydrogen, it also emits a line spectrum when it is energized.Helium has a more complex spectrum than hydrogen because it has more electrons.
As a result, it emits more lines than hydrogen. Helium has two electrons, which implies that it will have twice the number of lines than hydrogen.
The emission spectrum of helium will have more lines than that of hydrogen because helium has more electrons.
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