Enthalpy Review

Describe the energy change that takes place when a chemical reaction occurs.

• a) Energy is given out
• b) Energy is taken in
• c) Energy is taken in and then given out
• d) Energy is given out and then taken in

Tags

NGSS.HS-PS1-4

Which statement is true regarding endothermic reactions?

• a) Temperature change is positive and enthalpy change is positive
• b) Temperature change is positive and enthalpy change is negative
• c) Temperature change is negative and enthalpy change is positive
• d) Temperature change is negative and enthalpy change is negative

Which statement is true regarding exothermic reactions?

• a) Temperature change is positive and enthalpy change is positive
• b) Temperature change is positive and enthalpy change is negative
• c) Temperature change is negative and enthalpy change is positive
• d) Temperature change is negative and enthalpy change is negative

Tags

NGSS.HS-PS1-4

Heat is measured in 

• joules
• grams
• degrees celcius

Energy in exothermic reactions are

• released
• absorbed

Tags

NGSS.HS-PS1-4

Endothermic reactions feel

• warm
• cold

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

What type of reaction is shown in the reaction pathway?

• endothermic reaction
• exothermic reaction

Tags

NGSS.HS-PS1-4

N₂ +  3H₂ −->  2NH₃ 
How many moles of ammonium are produced when 3 moles of nitrogen react with hydrogen?

• 6 moles Ammonium
• 1.5 moles ammonium
• 9 moles ammonium
• 9 moles hydrogen

What is the symbol for enthalpy?

• H
• S
• G
• q

For which of these processes is the value of ΔH expected to be positive?

1. The temperature increases when calcium chloride dissolves in water.

2. Steam condenses to liquid water

3. Water boils

4. Dry ice sublimates

• 4 only

• 1 only

• 3 and 4 only

• 2 and 3 only