Chemical Reactions and Energy

Which of the following is a balanced equation?

• 4 Na + O₂ → 2 Na₂O

• 2 Na + O₂ → 2 NaO₂

• Na₂O + O₂ → 2 NaO

• Na₂ + O → Na₂O₂

Tags

NGSS.MS-PS1-5

CaCO₃ represents a chemical

• formula

• subscript

• symbol

• reaction

The minimum amount of energy needed to start a reaction is the.......

• activation energy

• exothermic energy

• chemical energy

• endothermic energy

What happens when chemical bonds break and new bonds form?

• a chemical change.

• mattered is destroyed.

• surface area increases.

• a physical change

Tags

NGSS.HS-PS1-4

In chemical reactions, what does the law of conservation of mass mean/

• Matter is not created or destroyed.

• The total mass of the reactants is greater than the total mass of the products.

• The total mass of the reactants is less than the total mass of the poducts.

• Matter is not changed.

Tags

NGSS.HS-PS1-7

In an exothermic reaction, heat is ...

• taken in
• given out

Tags

NGSS.HS-PS1-4

In an endothermic reaction, heat is ,,,

• taken in
• given out

Tags

NGSS.HS-PS1-4

What type of reaction occurs in a hand warmer

• exothermic
• endothermic

Tags

NGSS.HS-PS1-4

Baking bread and cooking an egg are examples of....?

• Endothermic processes
• Exothermic processess

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

If a chemical reaction is EXOTHERMIC, the temperature would....

• Stay the same
• Increase
• Decrease

Tags

NGSS.HS-PS1-4