Question 13

Each species that appears to the right of the arrow is called a

product.

Labels are used to indicate the physical state:

(g) gas (l) liquid (s) solid (aq) aqueous [dissolved in water] NH3(g) + HCl(g) → NH4Cl(s) SO3(g) + H2O(l) → H2SO4(aq)

13. Which statement regarding the complete combustion of a hydrocarbon is incorrect? a. The hydrocarbon is consumed in the reaction and must be shown in the balanced chemical equation. b. Heat is produced in the reaction but does not need to be shown in the balanced chemical equation. c. Balancing the chemical equation requires knowledge of the physical state of each reactant and each product. d. Oxygen is the oxidizing agent and must be shown in the balanced chemical equation. e. Carbon dioxide and water are produced in the reaction and must be shown in the balanced chemical equation.

c. Balancing the chemical equation requires knowledge of the physical state of each reactant and each product.

Hydrocarbons contain only

carbon and hydrogen.

Combustion of a compound that contains C and H (or C, H, and O) produces

carbon dioxide gas and liquid water. CH2O(l) + O2(g) → CO2(g) + H2O(l)

Balancing is achieved by writing stoichiometric coefficients to the left of the

chemical formulas. 2H2(g) + O2(g) → H2O(l)

A chemical equation uses chemical symbols to denote what occurs in a

chemical reaction. NH3 + HCl → NH4Cl

Chemical equations must be balanced so that the law of conservation of mass is

obeyed. H2(g) + O2(g) → H2O(l)

Combustion - a substance burns in the presence of

oxygen.

Each chemical species that appears to the left of the arrow is called a

reactant.

Decomposition

two or more products form from a single reactant CaCO3(s) →^ CaO(s) + CO2(g)

Combination

two or more reactants combine to form a single product NH3(g) + HCl(g) → NH4Cl(s)