Answer:
0.019 g.
Explanation:
where, P is the pressure of the gas in atm (P = 1.02 atm).
V is the volume of the gas in L (V = 15.0 L).
n is the no. of moles of the gas in mol (n = ??? mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 28°C + 273 = 301.0 K).
∴ n = PV/RT = (1.02 atm)(15.0 L)/(0.0821 L.atm/mol.K)(301.0 K) = 0.62 mol.
no. of moles = mass/molar mass.
∴ mass of oxygen = (no. of moles)(molar mass) = (0.62 mol)(32.0 g/mol) = 0.019 g.