Properties and Chemical Reactions: Mastery Test

Select the correct answer. Samuel adds a teaspoon of salt to a glass of water. He notices that the salt disappears. Samuel takes a sip to discover that the water tastes salty. What kind of change has occurred?

• It's a chemical reaction because a new substance has formed.

• It's a physical change because the water and the salt kept their original properties.

• It's an example of synthesis because two substances reacted to give one substance.

• It's a chemical reaction because the water now tastes salty but originally did not.

Select the correct answer. Carbon burns in the presence of oxygen to give carbon dioxide. Which chemical equation describes this reaction?

• carbon + oxygen + carbon dioxide

• carbon + oxygen → carbon dioxide

• carbon dioxide → carbon + oxygen

• carbon dioxide + carbon → oxygen

Select the correct answer. Iron oxide reacts with aluminum to give aluminum oxide and iron. What kind of chemical reaction is this?

• combustion

• decomposition

• replacement

• synthesis

Select the correct answer. What kind of chemical reaction does the chemical equation sodium + chlorine → sodium chloride represent?

• combustion

• decomposition

• single replacement

• synthesis

Select the correct answer from each drop-down menu. In certain fireworks, potassium nitrate breaks down into potassium oxide, nitrogen, and oxygen. This is an example of a _______ reaction. The opposite process is a _______ reaction.

• decomposition

• synthesis

• combustion

• neutralization

Select the correct images. Which images show chemical reactions?

Select the correct answer from each drop-down menu. The compound dinitrogen oxide is a gas at room temperature. The two elements found in a sample of this gas are:

• oxide

• carbon

• nitric acid

• oxygen