Chemistry Common Assessment Review Flashcardziz

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include hydrogen (H), oxygen (O), and copper (Cu).

Front

Is H2O an element?

Back

No, H2O (water) is not an element; it is a compound made of hydrogen and oxygen.

Front

What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together. For example, water (H2O) and sodium chloride (NaCl) are compounds.

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting ice or dissolving sugar in water.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. Examples include rusting iron or burning wood.

Front

Is dissolving sodium hydroxide in water a chemical or physical change?

Back

It is a physical change because the sodium hydroxide retains its chemical identity.

Front

Is wood rotting a chemical or physical change?

Back

Wood rotting is a chemical change because it results in the formation of new substances.

Front

What is a mixture?

Back

A mixture is a combination of two or more substances that are not chemically bonded. Examples include air, salad, and sand.

Front

What are electrons?

Back

Electrons are negatively charged subatomic particles that orbit the nucleus of an atom. They play a key role in chemical bonding.

Front

What is the difference between a compound and a mixture?

Back

A compound is a substance formed from two or more elements chemically bonded together, while a mixture is a combination of substances that are not chemically bonded.