Question

1. How many air molecules are in a 11.5×12.0×10.0 ft room? Assume atmospheric pressure of 1.00 atm, a room temperature of 20.0 ∘C, and ideal behavior.

Volume conversion:There are 28.2 liters in one cubic foot.

2. To identify a diatomic gas (X2), a researcher carried out the following experiment: She weighed an empty 6.3-L bulb, then filled it with the gas at 1.30 atm and 23.0 ∘C and weighed it again. The difference in mass was 9.5 g . Identify the gas.

Express your answer as a chemical formula.

3.

When heated, calcium carbonate decomposes to yield calcium oxide and carbon dioxide gas via the reaction

CaCO3(s)→CaO(s)+CO2(g)

What is the mass of calcium carbonate needed to produce 51.0 L of carbon dioxide at STP?

4. Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is

2C4H10(g)+13O2(g)→8CO2(g)+10H2O(l)

At 1.00 atm and 23 ∘C, what is the volume of carbon dioxide formed by the combustion of 4.00 g of butane?

5. A quantity of CO gas occupies a volume of 0.47 Lat 1.5 atm and 290 K . The pressure of the gas is lowered and its temperature is raised until its volume is 2.8 L .

Find the density of the CO under the new conditions.

6. A 48.5-mL sample of gas in a cylinder is warmed from 25 ∘C to 89 ∘C.

What is its volume at the final temperature? (Assume constant pressure.)

7. A balloon contains 0.128 mol of gas and has a volume of 2.84 L .

If an additional 0.164 mol of gas is added to the balloon (at the same temperature and pressure), what will its final volume be?