Chemistry A-LEVEL percentage atom economy HELP

Sodium azide NaN3 is a compound used in airbags when heated sodium azide decomposes as shown in the equation below (2NaN3(s)--->2Na(s)+3N2(g))nitrogen gas is used to inflate the airbags
1. calculate the percentage atom economy of this reaction
2. A driver's airbag is 56 cm³ when insulated to initiate the decomposition a temperature of 300k is required
3. In reality manufacturers work on an assumption that the percentage yield of the reaction is 90%. Calculate the actual mass in grams of sodium azide placed into the airbag?

Which part(s) are you stuck on?
From the wording, I’m not sure you’ve copied and pasted in all of part 2. Is part 2 meant to be working out the theoretical mass of sodium azide present in an airbag?

I've messed it up ,it has to be
The drivers airbag is 56cm³ when inflated .To initiate the decomposition a temperature 300K is required.Calculate the mass in g of sodium azide needed to inflate the air bag at 101KPa

The third one is about theoretical yield.
Am stuck at q2