Question 31

[zaf]

could u explain question 31 to me??
if the amt of CO2 decreases because it is soluble in water, then W decreases and therefore M decreases since they are directly proportional.. or am i wrong???
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[admin]

Good question. The problem with your reasoning is as follows: the apparatus should in this passage is designed to determine pressure P, which is the unknown. Though you are correct that in reality the weight W is decreased by the CO2 which dissolves in the water, there is no way to precisely calculate the decrease in W based on the information in the passage. In fact, quite the opposite.

The passage specifically states that W is calculated based on stoichiometry NOT experimentally. Thus the dissolving CO2 only changes one factor which is determined experimentally: the pressure P.

[admin]

Yes, the volume remains the same. And yes, if CO2 disolves then there is less P and that means M is greater due to the equation (w is determined prior to the experiment).