Bond Energy Unit 3

Is this equation endo- or exo-thermic?

PCl3 (s) + Cl2 (g) --> PCl5 (s) + energy

• endothermic

• exothermic

Tags

NGSS.HS-PS1-4

Is this equation endo- or exo-thermic?

2KNO3 (s) + energy --> 2KNO2 (s) + O2

• endothermic

• exothermic

Tags

NGSS.HS-PS1-4

How can we figure out if an overall reaction is endo- or exo-thermic? It is the difference between _______ and __________.

• hot and cold temperatures

• energy to break and energy to form bonds.

• time to form a bond versus time to break a bond

Tags

NGSS.HS-PS1-4

When new chemical bonds form, energy ____________.

• is taken into the system.

• is released from the system.

• stays the same in the system.

Tags

NGSS.HS-PS1-4

Based upon the graph above, what type of reaction is this?

• Endothermic

• Exothermic

Tags

NGSS.HS-PS1-4

Which of the following represents an exothermic reaction?

• 
• 

Tags

NGSS.HS-PS1-4

Which letter in the image above represents the products.

• A

• B

• C

• D

If you hold a container where a chemical reaction is taking place and it feels warm to you, this reaction is:

• endothermic

• exothermic

• isothermic

• what?

Tags

NGSS.HS-PS1-4

if the energy needed to break bonds is less than the energy released when new bonds are formed, the reaction will ........ energy and is .......

• absorb, endothermic

• release, exothermic

• release, endothermic

• absorb, exothermic

Tags

NGSS.HS-PS1-4

Do the reactants in an exothermic reaction have a higher or lower energy than the products?

• higher

• lower

Tags

NGSS.HS-PS1-4