Posted by Brandon on .
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.