How much heat is released when 47.50 g of ch4 (g) is burned in excess oxygen gas to produce carbon dioxide and water?

= 2113.44 kJ

Explanation:

When 1 mole of CH4 (g) burns in excess oxygen -714.0 kJ of heat is released.

For 47.50 g;

molar mass of CH4 = 16.042 g/mol

Number of moles of CH4

   = 47.5 g /16.042 g/mol

   = 2.96 moles

Therefore;

1 mole = -714.0 kJ

Heat change for 2.96 moles

 = 2.96 moles × -714.0 kJ

 = 2113.44 kJ

c is the answer because when something is left after something evaporates that shows the chemical change.