Answer:
36
Your question is not complere. but maybe it is like:
5 day expedition.
you'll need to heat 4.0kg
Air Temperature: 25 °C
each canister has 75 g
The standar heat of formation of propane at 25°C is −103.85 / kJmol...
If the data is not exactly the same, you can follow the same steps.
Explanation:
Given:
Weight of water = 4.0 kg = 4000 g
Boiling point = 100 °C (T2)
Initial T ° Water= 25 °C (T1)
Specific heat capacity water (Cs) = 4.184 J / g°C
Then
Energy (q) = m x Cs x (T2-T1)
q = 4000 g x 4.184 J / g°C x (100-25) °C
q = 1255200 J per day
For 5 days the amount of energy will be 5xq = 6276000 J = 6276 kJ
Then we know that the standard heat of formation of propane at 25°C is −103.85kJ/mol. Also, Molecular Weight propane= 44,1 g / mol
Then we can know how much propane it's needed:
Mass= 6276 kJ÷103.85 kJ / mol = 60.43 mol
Mass of propane= 60.43 mol × 44,1 g/mol = 2664.9 g
So, if each canister has 75.g of propane:
Number of canister= 2664.9 g ÷ 75.g = 35.53 = 36 canisters
