Indicate whether each of the following errors would cause the calculated molar m
ID: 1041553 • Letter: I
Question
Indicate whether each of the following errors would cause the calculated molar mass be too large, too small, or whether the error would have no effect. HINT: Rearrange the Ideal Gas Law so that it shows the molar mass (M) specifically, and note how M is related to each of the other quantities in the equation (directly proportional, inversely proportional, not related) 3. Correction for the vapor pressure of water is not made. 4. Water level inside flask higher than outside. 5. Temperature incorrectly read as 30° rather than 20°. 6. Apparatus is not allowed to cool to room temperature before proceeding. 7. Subtraction error leads to too large an apparent mass of oxygen. 8. More MnO2 than is called for in the instructions is added to the KCIOs. 9. Three grams of KCIOs is used rather than the 2.0 g called for in the instructionsExplanation / Answer
PV = nRT
n = m/M
Therefore,
PV = mRT / M
M = mRT / PV
3. When no correction is made for water pressure,used pressure for calculation is larger than the actual pressure ( corrected P = P - P? H2O )
Therefore M become too small
4. M become too large as Volume of the gas goes down when level of water increases.
5. M become too large as temperature is read as higher value than the actual value.
6.M become too large as it is not allowed to cool to room temperature;so it shows higher temperature as it s starting temperature.
7. M become too large as "m" calculated as larger value.