Consider the decomposition of solid calcium carbonate (limestone) to solid calcium oxide and gaseous carbon dioxide: CaCO3(s) ➡ CaO(s) + CO2(g)

Question

A 34.50 g piece of limestone is placed into a 1.50 L container and heated until the solid completely composes. What is the final pressure in the container when the temperature of the container returns to room temperature (25.0 °C).

Please use sig figs if possible.

Answer 1

First, determine how much CO2 is released from 34.50 g of CaCO3:

34.50 g CaCO3 x 1 mol CaCO3 /100.09 g CaCO3 x 1 mol CO2/ 1 mol CaCO3 = 0.3447 mols CO2

Now, we can use the ideal gas law to calculate the pressure of gas in the container given the mols of gas in the container:

PV=nRT

rearranging:

P= nRT/V = (0.3447 mols)(0.08206 L-atm/mol-K)(298.15 K) / (1.50 L)

= 5.62 atm

since the volume given is 3 sig figs, the final answer must have 3 sig figs