Question

question 9 of 10
what reactants form a combustion reaction?

a. water vapor and oxygen

b. a hydrocarbon and oxygen

c. hydrogen and water vapor

d. a hydrocarbon and water

Explanation:

A combustion reaction is a chemical reaction where a substance (usually a hydrocarbon, which is a compound made of hydrogen and carbon) reacts with oxygen, producing carbon dioxide, water, and energy (heat and light). Let's analyze each option:

• Option A: Water vapor and oxygen don't form a combustion reaction. Combustion needs a fuel (like a hydrocarbon), not water vapor.
• Option B: A hydrocarbon (fuel) reacting with oxygen is the definition of a combustion reaction. For example, methane ($CH_4$) burning in oxygen: $CH_4 + 2O_2

ightarrow CO_2 + 2H_2O$.

• Option C: Hydrogen and water vapor don't represent the reactants of a typical combustion reaction. Combustion requires oxygen, not water vapor, along with a fuel.
• Option D: A hydrocarbon and water don't form a combustion reaction. Combustion needs oxygen, not water, as a reactant.

Answer:

B. A hydrocarbon and oxygen