Answer:
1813.74g
Explanation:
Given parameters:
Number of moles of radon = 8.17moles
Unknown:
Mass of radon = ?
Solution:
To solve this problem, we use the expression below:
Number of moles =
Molar mass of radon = 222g/mol
Now insert the parameters and solve;
Mass of radon = Number of moles x molar mass
= 8.17 x 222
= 1813.74g
Methane CH4
ethane C2H6
propane C3H8
Butane C4H10
pentane C5H12
Answer: d) -705.55 kJ
Explanation:
Heat of reaction is the change of enthalpy during a chemical reaction with all substances in their standard states.

Reversing the reaction, changes the sign of 


On multiplying the reaction by
, enthalpy gets half:


Thus the enthalpy change for the given reaction is -705.55kJ