Thermochemistry

Match the definition below to the correct term. The enthalpy change that takes place when one mole of a compound is formed from its elements in their standard states under standard conditions.

• The enthalpy of neutralisation

• The enthalpy of combustion

• The enthalpy of formation

• The enthalpy of reaction

Define standard enthalpy of combustion.

• Heat released when one mole of substance is burnt completely in excess oxygen.

• Heat absorbed when one mole of substance is burnt completely in excess oxygen under standard state.

• Heat released when one mole of substance is burnt completely in excess oxygen under standard state.

• Heat change when one mole of substance is burnt partially in excess oxygen under standard state.

ΔH value in an endothermic reaction is a positive number.

• True

• False

Tags

NGSS.HS-PS1-4

Which of the following has a ΔH_f^o value of 0?

• Br₂(g)

• N(g)

• CO(g)

• N₂(g)

Twenty tortilla chips are combusted in a bomb calorimeter surrounded by 5 liters of water. The temperature of the water increases from 30℃ to 35℃. Assuming the heat capacity of the water is about 4 J/g∙ ℃ and the heat capacity of the calorimeter 2000 J/℃, what is the energy content of a single tortilla chip?

• 100 kJ

• 110 kJ

• 5.5 kJ

• 5 kJ

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

What type of reaction is this?

• Exothermic

• Endothermic

• Kinetic

• Potential

Tags

NGSS.HS-PS1-4

the study of energy changes that occur during chemical reactions and changes in state

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

NGSS.HS-PS3-4

If the enthalpy ter (ΔH) is negative the reaction is ____.

• Endothermic

• Exothermic

• Neutral

Tags

NGSS.HS-PS1-4

A positive ΔH means that:

• In order for the reaction to happen, heat must be input. It is exothermic

• In order for the reaction to happen, heat must be input. It is endothermic.

• When the reaction happens, heat is released. It is exothermic

• When the reaction happens, heat is released. It is endothermic

Tags

NGSS.HS-PS1-4

H₂ + ½ O₂ --> H₂O + 285kJ is an example of a(n)

• Electrical equation

• Heat equation

• Thermochemical equation

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1