Chemistry Quiz on Changes and Reactions

Melting chocolate is an example of:

• A new product being formed

• A chemical change

• Sublimation

• A physical change

Which of the following suggests that a chemical change has taken place?

• Heat and light are released

• The substance is dissolved

• The substance changes state

• The substance undergoes a non-permanent colour change

What are the reactants in this chemical equation? Copper + Nitric Acid → Copper Nitrate + Hydrogen

• Copper

• Copper and nitric acid

• Copper, nitric acid, and copper nitrate

• Copper, nitric acid, copper nitrate, and hydrogen

The substances present at the beginning of a chemical reaction are called

• products

• chemicals

• reactants

• enzymes

Rust is formed by a chemical reaction between iron, water, and oxygen. Identify the product of this reaction.

• Rust

• Water

• Iron

• Oxygen

Which of the following processes represent the state changes between a liquid and a gas?

• Melting and freezing

• Deposition and sublimation

• Evaporation and condensation

• Melting and evaporation

What happens when you cool a substance?

• The atoms cool down and lose energy.

• The atoms move less and pack closer to one another.

• The substance may undergo a change of state, such as freezing or condensing.

• All of the above.

Which of the following is NOT an example of a chemical change?

• Fruit ripens and changes colour.

• A pot of water boils and releases water vapour.

• Cooking an egg.

• Wood is burnt in a fireplace and ashes are left behind.

A student wants to conduct an experiment to find out how the reaction rate changes as the temperature of the reactants increases. The dependent variable will be:

• the temperature of the reactants

• how long it takes for the reaction to occur

• the hazards associated with carrying out the experiment

• the mass of the products of the reaction

A farmer applied different fertilizers to his cotton crops to see which one will make his plants grow the tallest. What is the independent variable?

• Type of fertilizer

• Growth of plants

• Height of plants

• Amount of fertilizer