Topic 3 Review

What are the REACTANTS in this reaction?

6 H2O + 6 CO2 --> C6H12O6 + 6 O2

• C6H12O6 + 6 H2O
• 6 H2O, 6 CO2
• 12 H2O + 3 CO2
• 6 O2, C6H12O6

Answer explanation

REACTANTS are the things you start with; they react with one another.

Tags

NGSS.MS-LS1-6

What are the PRODUCTS in this reaction?

6 H2O + 6 CO2 --> C6H12O6 + 6 O2

• 6 H2O, 6 CO2
• C6H12O6, 6 H2
• C6H12O6, 6 O2
• 6 O2, 6 CO2

Answer explanation

PRODUCTS are the things produced at the end of a chemical reaction.

Tags

NGSS.MS-PS1-5

NGSS.MS-LS1-6

Fe  + O2 →  Fe2O3.

What are the PRODUCTS?

• Fe

• O2

• Fe2O3

• Fe+O2

Answer explanation

Fe2O3 is the chemical formula for rust. 

Tags

NGSS.MS-PS1-5

Na + H2O --> NaO2H

Does the number of H atoms on the left match the number of H atoms on the right?

• yes

• no

• i don't know

• it doesn't matter

Tags

NGSS.MS-PS1-5

Is the following chemical equation balanced:

Na + H2O --> NaO2H

• Yes, all atoms we started with appear in the products.

• Yes, we start with 4 atoms and end with 4 atoms.

• No, the water is gone

• No, we start with 2H and 1 Oxygen but end with 1H and 2 Oxygen

Answer explanation

Na + H2O --> NaO2H

Reactants: Na = 1, H = 2, O = 1

Products: Na = 1, H = 1, O = 2

Tags

NGSS.MS-PS1-5

A baker buys a  quart of heavy cream. He then shakes it very hard for 15 minutes. He notices that the milk has turned into a solid: butter. Is this a physical change or a chemical change?

Answer explanation

Shaking cream is a physical change; we didn't add anything, we just shake it....and the result is BUTTER!

Tags

NGSS.MS-PS1-2

 Before roasting it, a marshmallow smells like sugar. After holding the marshmallow over a campfire for 30 seconds, the marshmallow smells like nuts.  Is this a physical change or a chemical change?

Answer explanation

The change in smell and color indicate a chemical change.

Tags

NGSS.MS-PS1-2

Bubbles form when two or more substances are combined ...

• Chemical Change
• Physical Change

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

How many TOTAL atoms are in the following molecule:  

H2SO4

Answer explanation

H2SO4

H = 2

S = 1

O = 4

TOTAL IS 7

Tags

NGSS.MS-PS1-1

Which of the following statements is true about chemical reactions?

• Energy is absorbed in every chemical reaction

• Bonds are broken and new bonds form.

• Energy is released in every chemical reaction.

• Matter is created during chemical reactions.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS3-5