Question

Sometimes in the lab we collect the O2gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolate and measure the amount of gas produced. Suppose the gas evolved by a certain chemical reaction taking place at 55.0C is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be 117mL. Calculate the mass of that is in the collection tube. Round your answer to significant digits. You can make any normal and reasonable assumptions about the reaction conditions and the nature of the gases.

Answer 1

mass CO = 0.12166 g

Step-by-step explanation:

Mass of CO = 0.12 grams

Explanation

Volume of CO gas = 117 mL = 0.117 L

Temperature of CO = 55.0 oC = 328 K

Assumption : Pressure of CO = atmospheric pressure = 1.0 atm

According to ideal gas law,

moles of CO = [(Pressure of CO) * (Volume of CO gas)] / [(R) * (Temperature of CO)]

where R = gas constant = 0.0821 L-atm/mol-K

moles of CO = [(1.0 atm) * (0.117 L)] / [(0.0821 L-atm/mol-K) * (328 K)]

moles of CO = 0.004345 mol

mass CO = (moles of CO) * (molar mass CO)

mass CO = (0.004345 mol) * (28.0 g/mol)

mass CO = 0.12166 g