Can someone check my answers? These are based off of an experiment which is determining the proportionality constant, R, in the ideal gas equation.
1. Suppose a student runs into some procedural and calculation difficulties. State the effect the following would have on the calculated R determined from this experiment.
a) After the reaction was completed, the student failed to withdraw the rod to its original position before taking the second buret reading.
answer: This would cause R to be much higher because the rod would push the chemicals in the buret up higher than they should be.
b) The student neglected to take into account the water vapor in the system while doing the calculations.
answer: The R would be lower and percent error negative. This would mess up most of the data because of bad recording.
c) The H2O2 solution had decompsed slightly after standing for awhile, so its concentration was somewhat lower than the laboratoy instructor had reported.
answer: The R would be higher because the H2O2 solutions concentration was lower. This would cause the data to be skewed and the buret reading to be a little off.
d)The student failed to read the barometric pressure at the time of the experiment. When she read the pressure the next day, it was 0.50 in. Hg higher than it had been during the experiment.
The R would be higher because the barometric pressure from one day to the next would change slightly and some of the solution could have evaporated.
2. a) Explain what is meant by the molar volume of a gas.
answer: The molar volume of a gas is the volume occupied by one mole of gas.
b) What assumption did you make about the molar volume of O2 when you performed your calculations for this experiment? Explain.
That the O2 would be lower than the moles of H2O2 reacting. I made the assumption because the O2 reacted from the H2O2 during the experiment.
See response to the original.
The answers listed here are incorrect.
yeah a majority of them are wrong
1. Let's check your answers for the effect of different factors on the calculated value of the proportionality constant, R:
a) After the reaction was completed, the student failed to withdraw the rod to its original position before taking the second buret reading.
Your answer: This would cause R to be much higher because the rod would push the chemicals in the buret up higher than they should be.
Correction: This would actually cause R to be lower, not higher. When the student fails to withdraw the rod to its original position, the volume of gas recorded would be larger than it should be. Since R is calculated by dividing the pressure and volume, the larger volume would result in a lower value of R.
b) The student neglected to take into account the water vapor in the system while doing the calculations.
Your answer: The R would be lower and percent error negative. This would mess up most of the data because of bad recording.
Correction: Neglecting to take into account the water vapor in the system would lead to an overestimation of the volume of the gas. This would result in a higher value of R, not lower. However, it is important to note that the percent error would depend on the magnitude of the error and the initial value of R.
c) The H2O2 solution had decomposed slightly after standing for a while, so its concentration was somewhat lower than the laboratory instructor had reported.
Your answer: The R would be higher because the H2O2 solution's concentration was lower. This would cause the data to be skewed, and the buret reading to be a little off.
Correction: The concentration of the H2O2 solution being lower than reported would not directly affect the value of R. The concentration of the reactants affects the number of moles, which in turn affects the volume of gas produced. However, since R is calculated using the ideal gas equation, any change in concentration would cancel out when calculating R.
d) The student failed to read the barometric pressure at the time of the experiment. When she read the pressure the next day, it was 0.50 in. Hg higher than it had been during the experiment.
Your answer: The R would be higher because the barometric pressure from one day to the next would change slightly, and some of the solution could have evaporated.
Correction: Neglecting to measure the barometric pressure during the experiment does not directly impact the value of R. However, changes in barometric pressure can affect the volume of gas recorded. If the pressure is higher during the second measurement, the volume of the gas would be slightly lower, leading to a slightly higher value of R.
2. a) Your answer for the definition of the molar volume of a gas is correct. The molar volume of a gas is the volume occupied by one mole of gas.
b) Your explanation regarding the assumption made about the molar volume of O2 during the calculations is unclear. Could you provide more details or clarification on this assumption?
To check your answers for the effects on the calculated proportionality constant, R, in the ideal gas equation, let's go through each situation:
1.a) When the student fails to withdraw the rod to its original position before taking the second buret reading, the calculated R would be much higher. This is because the rod would push the chemicals in the buret higher than they should be, resulting in an incorrect measurement of the volume. The proportionality constant, R, is directly affected by the volume measurement, and an incorrect volume would lead to an inaccurate value for R.
1.b) Neglecting to take into account the water vapor in the system while doing calculations would result in a lower calculated value for R. Water vapor contributes to the total pressure in the system, and not accounting for it would lead to an underestimate of the total pressure. This, in turn, would lead to a lower calculated value for R. Additionally, it would introduce negative percent error because the measured pressure would be lower than the actual pressure.
1.c) If the H2O2 solution had decomposed slightly and its concentration was lower than reported, the calculated R would be higher. This is because the concentration of the reactant affects the number of moles involved in the reaction, which in turn affects the pressure and volume. A lower concentration would result in fewer moles of gas produced, leading to a higher calculated R. It is important to have accurate concentration values to obtain reliable results.
1.d) The student's failure to read the barometric pressure at the time of the experiment and instead reading it the next day when it was 0.50 in. Hg higher would result in a higher calculated R value. Barometric pressure affects the overall pressure in the system, and a difference in pressure from one day to the next could indicate changes in the environment or solution composition. This could lead to slight variations in the measured pressure, affecting the calculated R value.
2.a) The molar volume of a gas refers to the volume occupied by one mole of gas at a given temperature and pressure. It is a measure of the volume per mole and is commonly expressed in liters per mole (L/mol). Molar volume is an important concept in the ideal gas law and allows for the comparison of different gases on an equal basis.
2.b) In the context of the experiment, it seems that you assumed the molar volume of O2 to be less than the moles of H2O2 reacting. This assumption is reasonable because during the reaction, the O2 gas is generated by the decomposition of the H2O2. As a result, the volume of O2 produced will be lower than the volume of H2O2 consumed. This assumption allows for the correct interpretation of the stoichiometry of the reaction and the calculations based on it.