Answer:
68.6 % of the compound is carbon
Explanation:
Step 1: Data given
Mass of 7.40 mg = 0.0074 grams
Mass of carbon dioxide = 18.6 mg = 0.0186 grams
Molar mass CO2 = 44.01 g/mol
Step 2: Calculate moles CO2
Moles CO2 = mass CO2 / molar mass CO2
Moles CO2 = 0.0186 grams / 44.01 g/mol
Moles CO2 = 4.23*10^-4 moles
Step 3: Calculate moles C
For 1 mol CO2 we have 1 mol C
For 4.23*10^-4 moles CO2 we have 4.23*10^-4 moles C
Step 4: Calculate mass C
Mass C = 4.23*10^-4 moles * 12.01 g/mol
Mass C = 0.00508 grams
Step 5: calculate the mass percentage of carbon
% C= (0.00508 grams / 0.0074 grams ) * 100 %
% C = 68.6 %
68.6 % of the compound is carbon
