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.
Can anyone help me?
Unless we have done the exact experiment which you have done, then we really don't know what is going on.
Wow, Brandon! WOW!!
is this Prop379 determining prooportionality constant
I can help you review your answers and provide guidance on the concepts involved in your questions.
1. 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 states that this would cause R to be much higher because the rod would push the chemicals in the buret up higher than they should be. This is incorrect. The position of the rod would not affect the calculated value of R. The volume of gas in the buret would be determined by the difference in readings before and after the reaction, irrespective of the rod position. The effect of not withdrawing the rod would be that the initial and final volumes recorded would be inaccurate, leading to incorrect calculations of the volume of gas evolved.
b) The student neglected to take into account the water vapor in the system while doing the calculations.
Your answer states that the R would be lower and the percent error negative. This is incorrect. Neglecting the water vapor would not affect the value of R directly. However, it would lead to an incorrect determination of the number of moles of the gas, resulting in an incorrect value for R and potentially negative percent error, depending on the direction of the error.
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 states that the R would be higher because the H2O2 solution's concentration was lower. This is correct. If the H2O2 concentration is lower than expected, it would result in a lower number of moles of H2O2 reacting, leading to an overestimate of the volume of gas evolved. This would result in a higher value for 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 states that the R would be higher because the barometric pressure from one day to the next would change slightly, and some solution could have evaporated. This is incorrect. The change in barometric pressure alone would not affect the calculated value of R. However, the barometric pressure is necessary to determine the correct pressure of the gas in the experiment. If the pressure is higher than recorded, it would result in an overestimation of the volume of gas evolved, leading to a higher value for R.
2. a) Explain what is meant by the molar volume of a gas.
Your answer states that the molar volume of a gas is the volume occupied by one mole of gas. This is correct. The molar volume of a gas represents the volume occupied by one mole of the gas at a specific temperature and pressure.
b) What assumption did you make about the molar volume of O2 when you performed your calculations for this experiment? Explain.
Your answer states that you assumed the molar volume of O2 would be lower than the moles of H2O2 reacting because the O2 reacted from the H2O2 during the experiment. This assumption is incorrect. The molar volume of O2 would be unrelated to the moles of H2O2 reacting. The molar volume of O2 would be consistent with the molar volume of any ideal gas at the same temperature and pressure, as per the ideal gas law.
To summarize, I have provided corrections and explanations for each question. Remember to consider the direct effects and relationships between variables when analyzing experimental results.