Which statement about bonding is correct?

Consider the following reactions.

Cu₂O(s) + O₂(g) → 2CuO(s) ∆H^O = –144 kJ

Cu₂O(s) → Cu(s) + CuO(s) ∆H^O = +11 kJ

What is the value of ∆H^O, in kJ, for this reaction?

Cu(s) + O₂(g) → CuO(s)

Consider the two reactions involving iron and oxygen.

2Fe(s) + O₂(g) → 2FeO(s) ∆H^O = –544 kJ

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s) ∆H^O = –1648 kJ

What is the enthalpy change, in kJ, for the reaction below?

4FeO(s) + O2(g) → 2Fe₂O3(s)

Which processes have a negative enthalpy change?

I. 2CH₃OH(l) + 3O₂(g) → 2CO₂(g) + 4H₂O(l)

II. HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

III. H₂O(g) → H₂O(l)

Which equation represents the bond enthalpy for the H–Br bond in hydrogen bromide?

Which types of reaction are always exothermic?

I. Neutralization

II. Decomposition

III. Combustion

A pure aluminium block with a mass of 10 g is heated so that its temperature increases from 20 °C to 50 °C . The specific heat capacity of aluminium is 8.99 × 10^–1 J g^–1 K^–1. Which expression gives the heat energy change in kJ?

Which statement is correct given the enthalpy level diagram below?

Identical pieces of magnesium are added to two beakers, A and B, containing hydrochloric acid.

Both acids have the same initial temperature but their volumes and concentrations differ.

Which statement is correct?

The specific heat of iron is 0.450 J g^–1 K^–1. What is the energy, in J, needed to increase the temperature of 50.0 g of iron by 20.0 K?

Consider the reaction between magnesium and hydrochloric acid. Which factors will affect the reaction rate?

I. The collision frequency of the reactant particles

II. The number of reactant particles with E ≥ Ea

III. The number of reactant particles that collide with the appropriate geometry

Use the average bond enthalpies below to calculate the enthalpy change, in kJ, for the following reaction.

H₂(g) + I₂(g) → 2HI(g)

Which equation represents the reaction for which the enthalpy change, ΔH, is the mean bond energy of the C-F bond?   

Consider the bond enthalpy values in the table.

For the reaction

H-O-O-H(g) $$\rightarrow$$ H-O-H(g) + 1/2 O=O(g)

the enthalpy change, in kJ mol⁻¹, is

Using the data in the table below, calculate the standard enthalpy change, in kJ mol⁻¹, for the reaction between carbon disulfide, CS₂, and oxygen shown in the following equation.

CS₂(g) + 3O₂(g) → CO₂(g) + 2SO₂(g)

When 10 cm³ of 2 mol dm⁻³ hydrochloric acid is reacted with 10 cm³ of 2 mol dm⁻³ sodium hydroxide solution, the temperature change is ΔT.

HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

When the reaction is repeated with 50 cm³ of each solution, the temperature change is

In an endothermic reaction in aqueous solution, which of the following is correct?