Thermochemistry

During an exothermic reaction, heat content in the surroundings increases because

• heat energy is destroyed during reactions

• the reaction absorbs heat energy

• the energy contained in the reactants is lower then the products

• the energy contained in the products is lower than the reactants

What type of reaction is shown in the picture?

• endothermic
• exothermic

Releasing heat into the surroundings occurs during an ___________________ reaction.

• Exothermic

• Endothermic

• Kinetic Energy

• Thermal Energy

ΔH value in an endothermic reaction is a positive number.

• True
• False

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

What does the circle mean in ΔH°?

• Standard Conditions (T=298.15 K P=1 atm)

• Standard Temperature and Pressure (T=273.15 K P=1 atm)

• Degree K

• Degree C

How do you calculate Enthalpy of a reaction?

• ΔH = ΔH_products - ΔH_reactants

• ΔT = q / mC

• ΔG = ΔH -TΔS

• E = mc²

"Heat change when 1 mole of gaseous atom is formed from its element at standard states" is the definition for _______.

• standard enthalpy of formation

• standard enthalpy ofhydration

• electron affinity

• standard enthalpy of atomisation

Name the type of enthalpy for the following reaction:

Na⁺ (g) --> Na⁺ (aq) ΔH = -364 kJmol^-1

• Standard enthalpy of neutralisation, ΔH_neut^o

• Standard enthalpy of solution, ΔH_soln^o

• Standard enthalpy of hydration, ΔH_hyd^o

• lattice energy, ΔH_lattice^o

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.