Chemistry Unit 3 Lessons 1 and 2

What is a good definition of fuel?

• A material that can react to release energy (often by combustion)

• Something that can combust when heat is added

• A material that absorbs energy

• Something that runs a motor

Tags

NGSS.HS-PS1-4

The temperature at which a compound gives off enough vapor to ignite in the air and burn is called a

• flash point.

• combustion point.

• ignition point.

• burning point.

In an exothermic reaction,

• heat goes out of the system (is released).

• heat enters the system (is absorbed).

• heat is not necessarily involved.

• the temperature of the surrounding area drops.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

In an endothermic reaction,

• heat goes out of the system (is released).

• heat enters the system (is absorbed).

• heat is not necessarily involved.

• the temperature of the surrounding area rises.

Tags

NGSS.HS-PS1-4

Which are always true of chemical reactions? Select all that apply.

• The new substance has new properties.

• The new substance will have properties similar to at least one of the original substances.

• Atoms are rearranged.

• Atoms are added.

• They are always hot.

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NGSS.HS-PS1-7

What is the solid part of a chemical reaction called?

• Precipitate

• Chunks

• Sediment

• Soliditary

Which of the following are true of organic substances? Select all that apply.

• They are carbon-based.

• They are oxygen-based.

• They are derived from living things or once living things.

• They are healthy to eat.

• They are not combustible.

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NGSS.HS-LS1-6

Which of the following are true of combustion?

• It requires oxygen.

• It often gives off carbon dioxide.

• It is a chemical reaction.

• It gives off oxygen.

• It can proceed without any activation energy.

What is the best definition of activation energy?

• Energy required to start a chemical reaction

• Energy required to start combustion

• Energy given off by a chemical reaction

• Energy that is transferred during a chemical reaction

Tags

NGSS.HS-PS1-4

Which are true of physical changes?

• The form of a substance changes.

• The atoms in the substance are rearranged.

• A new substance forms.

• No new substance forms.

• Color always changes.