Energetics

Which of the following is true about the formation of bonds between molecules?

• Energy is given off when bonds are formed between molecules.

• Energy is absorbed by the molecule when bonds are formed.

• Energy is neither given off nor absorbed when bonds are formed.

Tags

NGSS.HS-PS1-4

Which of the following statement is true about the breaking of bonds between molecules?

• To break a bond between molecules, energy must be released by the molecule

• To break a bond between molecules, no energy is needed.

• To break a bond between molecules, energy must be absorbed by the molecule.

Tags

NGSS.HS-PS1-4

What is the activation energy?

• The energy of the products
• The energy of the reactants
• The minimum energy needed by the reactants to form the products.
• The energy lost in the reaction

If ∆H is negative, the reaction is?

• exothermic
• endothermic

Tags

NGSS.HS-PS1-4

ΔH value in an endothermic reaction is a positive number.

• True
• False

Endothermic reactions feel

• warm

• cold

Tags

NGSS.HS-PS1-4

Exothermic reactions feel

• warm

• cold

Tags

NGSS.HS-PS1-4

Which example would be considered exothermic?

• Melting Ice

• Photosynthesis

• Making ice cubes

• Cooking an egg

Tags

NGSS.HS-PS1-4

In an exothermic reaction, heat is ...

• taken in or absorbed
• given out or released

Tags

NGSS.HS-PS1-4

In an endothermic reaction, heat is ...

• taken in or absorbed
• given out or released 

Tags

NGSS.HS-PS1-4