The purity of the copper (II) carbonate will be equal to 79.3%.
Start with the balanced chemical equation for this decomposition reaction
Notice that you have a
Since you didn't provide the pressure and temperature conditions, I'll assume you're at STP (Standard Pressure and Temperature).
At STP , which implies a pressure of 100 kPa and a temperature of 273.15 K, 1 mole of any ideal gas occupies exactly 22.7 L. This is known as the molar volume of a gas at STP.
You can use the molar volume of a gas to determine how many moles of carbon dioxide were produced by the reaction
According to the aforementioned mole ratio, if this many moles of
Use the compound's molar mass to determine how many grams would contain this many moles
Since the total sample weighs 24.8 g, its purity will be
SIDE NOTE Many problems still require you to use the old definition of STP, which specify a pressure of 1 atm and a temperature of 273.15 K. At that pressure and temperature, the molar volume of a gas is 22.4 L.
If your teacher or instructor wants you to use those values for pressure and temperature, simply redo the calculations using 22.4 L instead of 22.7 L.