Urgent chem help?

Start with 74.4L N2 gas. End with g NaN3. Multiply the 74.4L N2 by 1mol N2/22.4L N2. This is the molar volume of an ideal gas at STP. The L N2 cancel to give moles of N2 gas. Multiply by 2mol NaN3/3mol N2. This comes from the balanced equation. The mol N2 cancel to give the moles NaN3. Multiply by 65g NaN3/1mol NaN3. The mol NaN3 cancel, giving g NaN3, the m. Atomic weights: Na=23, N=14.