1. States of Matter Practice (3)

Calcium carbonate is a compound that can decompose into carbon dioxide and calcium oxide. Carbon dioxide, in turn, is made up of the elements carbon and oxygen. What needs to happen to a compound in order for it to be broken down into either elements or simpler compounds? a. The compound needs to undergo a chemical reaction. b. The compound needs to undergo a physical change. c. The compound needs to be distilled in order to be reduced to simpler components. d. The compound needs to be filtered in order to be reduced to simpler components.

The correct answer is A: The compound needs to undergo a chemical reaction. Explanation: A compound can only be reduced to elements or simpler compounds by a chemical reaction.

Which one of the following is not a solid at room temperature? a. wood b. air c. stainless steel d. rubber

The correct answer is B: air Explanation: This is the only choice that is a gas. The other three choices are all solids.

What distinguishes a mixture from a pure substance? a. A mixture consists of two or more phases, but a pure substance is only one phase. b. A mixture is a combination of two or more substances that are physically separable, and a pure substance is not physically separable. c. A pure substance consists of a single element, but a mixture consists of more than one elements. d. A mixture is a type of pure substance where two or more types of elements are combined to form a compound.

The correct answer is B: A mixture is a combination of two or more substances that are physically separable, and a pure substance is not physically separable. Explanation: Mixtures are more than one compound that are not chemically combined.

Which of the following is characteristic of a liquid? a. fixed volume and fixed shape b. fixed volume and variable shape (that depends on the container) c. variable volume and variable shape (depending on the container) d. variable volume and fixed shape

The correct answer is B: fixed volume and variable shape (that depends on the container) Explanation: A liquid has a fixed volume (e.g., 1 liter) but not a fixed shape. To picture this, imagine pouring a liter of orange juice into 3 different liter containers, each of which has a different shape. The volume will always be 1 liter, but the shape of the liquid in each container will be different.

Which of the following is not a pure substance? a. oxygen b. iron c. blood d. distilled (or pure) water

The correct answer is C: blood Explanation: Blood is made up of water, various chemicals, and cells. The different components of blood can be separated by physical process (e.g., a centrifuge to separate the cells).

Carbon dioxide bubbles can be found in many drinks, including sodas, some mineral waters, and beer. Which two phases of matter are present in drinks that contain carbon dioxide? a. gas and solid b. solid and liquid c. gas and liquid d. solid, liquid, and gas

The correct answer is C: gas and liquid Explanation: These drinks generally contain liquids mixed with CO2, or carbon dioxide.

When you squeeze an inflated balloon, you change both the volume and the shape. Which choice gives the correct phase of the contents in the balloon and also explains why the matter is categorized in that phase? a. liquid; the volume and shape are fixed b. gas; the volume is fixed but the shape can be changed c. gas; the volume and shape are variable d. liquid; the volume is constant and the shape is variable

The correct answer is C: gas; the volume and shape are variable Explanation: There is gas inside the balloon. The volume and the shape (as well as the pressure) of the gas depend on the balloon (i.e., the container), so the volume and the shape are variable.

Chemists categorize matter into three different phases or states. Which of the following is not a general phase or state of matter? a. solid b. liquid c. solution d. gas

The correct answer is C: solution Explanation: A solution is a homogeneous mixture.

Which of the following describes the characteristics of matter in the gas phase? a. The volume is constant but the shape can vary. b. The shape is constant but the volume can vary. c. The volume and shape are constant. d. The volume and the shape are not fixed.

The correct answer is D: The volume and the shape are not fixed. Explanation: The volume and the shape of matter in the gas phase are determined by the container and therefore not fixed.

Which of the following is not a mixture? a. beer b. granola bar c. grape drink d. oxygen gas

The correct answer is D: oxygen gas Explanation: Oxygen gas is comprised only of oxygen molecules, so it can be considered as an element (oxygen), which is a subcategory of a pure substance, not a mixture. To distinguish this substance from a mixture, you have to ask yourself if the pure oxygen gas can be broken down (by a physical technique) into separate substances.