How many moles and how many grams of carbon do you need to burn to obtain 45 dm3 of carbon dioxide?

Given:
V (CO2) = 45 dm3 = 45 l

Find:
n (C) -?
m (C) -?

1) Write the equation of a chemical reaction:
C + O2 => CO2;
2) Calculate the amount of substance CO2:
n (CO2) = V (CO2) / Vm = 45 / 22.4 = 2 mol;
3) Determine the amount of substance C (taking into account the coefficients in the reaction equation):
n (C) = n (CO2) = 2 mol;
4) Using the periodic system of D.I.Mendeleev, calculate the molar mass C:
M (C) = Ar (C) = 12 g / mol;
5) Calculate the mass C:
m (C) = n (C) * M (C) = 2 * 12 = 24 g.

Answer: The amount of substance C is 2 mol; weight – 24 g.