Answer:
A
Explanation:
CH4+O2-CO2+ H20
that mean methane has burn in oxygen to produce CO2
Refer to attachment for your answer
To do this problem it is necessary to take into account that the heat given by the unknown substance is equal to the heat absorbed by the water, but considering the correct sign:

Clearing the specific heat of the unknown substance:

Answer:
formula pottasium Oxalate C2k204
Explanation:
C2k204