Oquizy

Which statement correctly defines enthalpy change (ΔH)?

The change in energy of bonds only The energy needed to start a reaction The heat change at constant pressure The temperature change of the surroundings

What type of reaction does this diagram represent?

Combustion only Endothermic Exothermic Reversible

What does the upward arrow represent?

Activation energy Energy absorbed – endothermic Energy of products only Energy released – exothermic

Which statement is correct?

Bond breaking is endothermic Bond breaking is exothermic Bond making is endothermic Bond making requires energy

John adds 25 cm³ of 1.0 mol/dm³ HCl to 25 cm³ of 1.0 mol/dm³ NaOH in a polystyrene cup. The temperature rises from 25.0 °C to 31.0 °C.
What is the temperature change?

+6.0 °C 25.0 °C 56.0 °C –6.0 °C

Why is a polystyrene cup used in calorimetry experiments?

To absorb extra heat To allow faster mixing To cool the solution To minimise heat loss to the surroundings

Quiz: Chemistry - Chemical Energetics