a. That has no effect on the calculated moles of O2 gas in the collection vessel. In the experiments I've seen one weighs the KClO3 test tube both before and after heating to expel O2 gas. That different in mass of the two weighings tells you how much weight was lost and that translates into the mols O2 gas evolved.
b. The water level in the collection bottle is higher than the water level in the tank holding the bottle. Therefore, the pressure outside the bottle is higher than the pressure inside the bottle and the volume of O2 gas is less than when the water level is lowered by equilibration.
c. See answer a above.
. O2 gas is slightly soluble in water. How does this affect the reported moles of KClO3 decomposed in the mixture? Explain.
2.
a. When the water level inside the gas collecting test tube is higher than it is outside, is the O gas pressure greater or less than atmospheric pressure? Explain.
b. When you equilibrate the gas pressures in Question 2a, does the volume of Ogas increase or decrease? Explain.
c. Suppose you did not equilibrate the gas pressure to atmospheric pressure, but assumed the pressure of the O gas equals atmospheric pressure. Are the reported moles of evolved Ogas greater or less than actual? Explain.
1 answer