Characteristics of Chemical Reactions

Front

How do we know that a chemical reaction has occurred when hydrogen and oxygen react to form water?

Back

The hydrogen and oxygen atoms regroup into a new molecule.

Front

Which of the following statements is true?
- We know combining Substances A and B resulted in a chemical reaction because a gas was formed
- We know combining Substances C and D resulted in a chemical reaction because of the lack of a temperature change
- We know combining Substances A and B resulted in a chemical reaction because of the lack of a temperature change
- We know combining Substances A and B resulted in a chemical reaction because of the lack of a temperature change

Back

We know combining Substances A and B resulted in a chemical reaction because a gas was formed

Front

What is the best description of the results of a chemical reaction?

Back

A new substance with different properties is formed

Front

Rust forming on a piece of iron is an example of which of the following:

A physical change because the process can be reversed

,

A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms

,

The natural process of decay as metallic ions age

,

A violation of the laws of physics because new mass has been created

Back

A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms

Front

Which of the following statements is true?

• Cutting paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone
• Freezing water is an example of a chemical reaction because a new substance is formed and the process cannot be undone
• Melting ice is an example of a chemical reaction because a new substance is formed and the process cannot be undone
• Burning paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone

Back

Burning paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone

Front

Hint: gas bubbles are being produced. Chemical reaction or not?

Back

yes

Front

Chemical reaction or not?

Back

no

Front

Chemical reaction or not?

Back

no

Front

Glow stick has been cracked. Chemical reaction or not?

Back

yes

Front

Is bike rusting a chemical reaction?

Back

Yes