Internal energy calculations?

Question

please help me to analys this and please give the answer and solution.....
using this formula
q(sub)v = n C(sub)v dT


1. how much heat is released when 4.50g of methane gas is burned in a constant-pressure system? One mol of methane gas combined with 2 moles of oxygen releases 890 kJ of heat.

2. the specific heat of water is 4.18 J/g-k. If 10.0g of water is heated from 25degrees celcius to 50degrees celcius at constant pressure, how much heat is needed? What is the molar heat capacity of water.

Answer 1

Molar mass of CH4 is 16 g

Thus heat released is 890*4.5/16 kJ

10*25*4.18 J