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

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.

it's c. elements are placed in rows based on how may valencies electrons have.