Unit 2A Chemical Formulas/Reactions Review

What is a chemical reaction?

• 
  a change in matter when the molecules rearrange to make new molecules

• 
  a change in matter when the physical appearance changes

• a change in matter when matter changes its form or appearance

• a very boring change in matter

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

This change is a...

• Chemical reaction

• physical change

• chemical change

• physical reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The reactants in the image above are:

• 
  CH4 and 2O2

• 2H2O and CO2

• CH4

• 2O2

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

You know that a chemical reaction is occurring here because you see __________________ . (pick 2)

• Color change

• Gas production

• Temperature change

• New solid formed

Tags

NGSS.MS-PS1-2

You know that a chemical reaction is occurring here because you see __________________ .

• Creates a new solid

• Produces gas

• Odor/light production

• Temperature change

Tags

NGSS.MS-PS1-2

A precipitate is a ___________ that forms when 2 liquids react together.

• liquid

• gas

• plasma

• Solid

How is a chemical change different from a physical change?

• there is no difference between the two

• a chemical change creates a new substance

• a physical change creates a new substance

• a chemical change always changes states of matter

Tags

NGSS.MS-PS1-2

How many atoms of nitrogen (N) are found in this substance?

• 1

• 2

• 8

• 14

Tags

NGSS.MS-PS1-1

The chemical formulas for four substances are listed below. Which substance has exactly 4 atoms of carbon in every molecule?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-1

Select all that apply: What does a chemical formula always tell you?

• What elements are in the compund

• How many atoms of each element are in a molecule of the substance

• The atomic number and mass of the substance

• The number of molecules present

Tags

NGSS.MS-PS1-1