Given the equation: 2c2h2 (g) + 5o2 (g) → 4 co2 (g) + 2h2o(g)how many moles of oxygen are required to react completely with 1.0mole of c2 h2 ? (1) 2.5 (3) 5.0(2) 2.0 (4) 10

The answer is (1) 2.5 moles. The ratio of the reactants consumed are the same as the ratio of the coefficient before the compounds. So the moles of oxygen consumed is 1/2*5 = 2.5 moles.

Ibelieve your answer is true 

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.