What volume (in milliliters) at stp will be occupied by 0.0035 mol of methane, ch4?

Answer is: volume of methane is 78.4 mL.

n(CH₄) = 0.0035 mol.

At standard pressure and temperature:

V(CH₄) = n(CH₄) · Vm

V(CH₄) = 0.0035 mol · 22.4 L/mol.

V(CH₄) = 0.0784 L · 1000 mL/L = 78.4 mL.

Vm - molar volume.