Chemical Reactions Exercises

Which of the following materials undergoes a chemical change?

• Cutting of stainless metal plates

• Crushing chunks of ice

• Dissolving sugar in water

• Rotting of tomatoes

What are the substances that are present before a chemical reaction occurs?

• Coefficients

• Products

• Reactants

• Subscripts

Which symbol in a chemical equation represents "yields" or "produces"?

• +

• →

• =

• ↑

Which of the following is NOT an evidence of a chemical reaction?

• Change in temperature

• Evolution of gas

• Melting of ice

• Formation of precipitate

What law states that matter cannot be created nor destroyed in a chemical reaction?

• Law of Conservation of Mass

• Law of Definite Proportions

• Law of Multiple Proportions

• Law of Chemical Change

What happens to the mass of reactants and products in a chemical reaction?

• The mass of products is greater.

• The mass of reactants is greater.

• They must be equal.

• There is no relationship.

What happens when quicklime (CaO) is mixed with water?

• Change in temperature

• Formation of bubbles

• Evolution of light

• Production of mechanical energy

In the chemical equation H₂ + O₂ → H₂O, what are the products?

• H₂ and O₂

• O₂ and H₂O

• H₂O

• H₂

Which of the following best describes a combustion reaction?

• A reaction where two elements combine to form a new product

• A reaction where oxygen reacts with a hydrocarbon to form carbon dioxide and water

• A reaction where a compound breaks down into simpler substances

• A reaction where ions are exchanged between two reactants

Which type of reaction is represented by AB → A + B?

• Combination

• Decomposition

• Single replacement

• Double replacement