III. Chemical Reactions

The smallest part of an element that still has the properties of that element.

• mass

• an atom

• weight

Amount of matter in an object.

Downward pull on an object by gravity's Earth.

• mass

• weight

• an atom

Answer explanation

Mass is the amount of matter in an object. Weight is the downward pull on an object by Earth’s gravity. The mass of an object is the same on Earth, in space, or on other planets, but the weight of the object depends on where the object is.

Soil is an example of a ________ ________. It contains grains of sand, clay, and other materials

• physical change

• natural mixture

• chemical change

Melting butter is an example of a ________ ________.

• physical change

• natural mixture

• chemical change

• conservation

Answer explanation

Melting butter is an example of a physical change. The butter becomes liquid, but it is still butter.

Burning a piece of paper is a ________ _______.

• conservation

• chemical change

• physical change

Answer explanation

Burning a piece of paper is a chemical change. The paper becomes smoke, gas, and ash that have different properties from the original paper.

____________ means that something stays the same.

Answer explanation

Conservation means that something stays the same. When matter goes through a chemical reaction, many of its properties change, but the total number of atoms involved in the reaction is the same before and after. The total mass involved in the reaction is also the same before and after. In a chemical reaction, the amount of matter is conserved—it remains the same.

The periodic table allows scientists to predict the chemical behavior of an element by looking at its position in the table.

If an element is found on the last column of the periodic table, it must be a __________ gas that does not react easily with other elements.

• metal

• colorless

• colorful

The periodic table allows scientists to predict the chemical behavior of an element by looking at its position in the table.

If an element is in the same column as gold, it is probably a ________ because gold is a ________.

• gas

• metal

• liquid

What is the main difference between a heterogeneous mixture and a homogeneous mixture?

• In a homogeneous mixture, the components are not evenly spread throughout the mixture. In a heterogeneous mixture, the components are evenly spread throughout the mixture.

• In a heterogeneous mixture, the components are difficult to see and are spread out uniformly throughout the mixture.

• In a homogeneous mixture, the components are easy to see and are well mixed so the components show up in different parts of the mixture.

• In a heterogeneous mixture, the components are not evenly spread throughout the mixture. In a homogeneous mixture, the components are evenly spread throughout the mixture.