How many grams of carbon dioxide gas are in a 1.0-l balloon at stp?

Used the Ideal gas law to get the grams of carbon dioxide

PV=nRT  Where p is pressure, v is volume, n is a number of moles, t is temperature and r is the ideal gas constant. The value of R is 0.0821.

Solution
First, find the mole of carbon dioxide

n= PV/RT
  = 1 x 1.0 / 0.081 x (2.73 x 102)
  = 1 / 0.081 x 278.46
  = 1 / 22.56
  = 0.045 mol

Convert the moles into grams
Grams of CO2 = 0.045 mol x 44 g/mol = 1.98 g

So the grams of CO2 is 1.98g