Energetics - exam practice

they are averaged out over many molecules with different kinetic energies

they are averaged out over different compounds containing the same bond

they are the averages of the bond in liquid and gaseous compounds

they are average values from different data books

the energy required to produce one mole of bromine atoms in the gaseous state

the energy required to produce one mole of bromine atoms in the liquid state

the energy required to break one mole of Br-Br bonds in the gaseous state

the energy required to break one mole of Br-Br bonds in the liquid state

-1,106 kJ mol^-1

-540 kJ mol^-1

-254 kJ mol^-1

+1,106 kJ mol^-1

0.068 g

1.85 g

3.94 g

4.48 g

H_2(g) + 0.5O_2(g) ➔ H₂O_(g)

H_2(g) + 0.5O_2(g) ➔ H₂O_(l)

2H_2(g) + O_2(g) ➔ 2H₂O_(g)

2H_2(g) + O_2(g) ➔ 2H₂O_(l)

0.418 kJ

10.4 kJ

41.8 kJ

62.7 kJ

ΔH_f^⦵(CH₄) + ΔH_f^⦵(CO₂) - 2ΔH_f^⦵(H₂O)

ΔH_f^⦵(CO₂) + 2ΔH_f^⦵(H₂O) + ΔH_f^⦵(CH₄)

ΔH_f^⦵(CH₄) + 2ΔH_f^⦵(H₂O) - ΔH_f^⦵(CO₂)

ΔH_f^⦵(CO₂) + 2ΔH_f^⦵(H₂O) - ΔH_f^⦵(CH₄)

-62.7 kJ mol^-1

-31.4 kJ mol^-1

-15.7 kJ mol^-1

-3.14 kJ mol^-1

the total bond energy of the products is more than the total bond energy of the reactants, and ΔH for the reaction is positive

the total bond energy of the products is less than the total bond energy of the reactants, and ΔH for the reaction is negative

the total bond energy of the products is less than the total bond energy of the reactants, and ΔH for the reaction is positive

the total bond energy of the products is more than the total bond energy of the reactants, and ΔH for the reaction is negative

-418 kJ mol^-1

-88 kJ mol^-1

+88 kJ mol^-1

+418 kJ mol^-1

less energy is released on bond making than is taken in during bond breaking

the enthalpy change for the reverse equation is +184.6 kJ mol^-1

the enthalpy change of formation of HCl_(g) is -184.6 kJ mol^-1

the temperature decreases during the reaction

-372 kJ mol^-1

-500 kJ mol^-1

-800 kJ mol^-1

-1,298 kJ mol^-1

Ag_(g) + 0.5I_2(g) ➔ AgI_(s)

Ag_(s) + 0.5I_2(s) ➔ AgI_(s)

Ag⁺_(g) + I^-_(g) ➔ AgI_(s)

Ag⁺_(aq) + I^-_(aq) ➔ AgI_(s)

-679

-794

-1,024

-1,139

+112 kJ mol^-1

-112 kJ mol^-1

+746 kJ mol^-1

-746 kJ mol^-1

the reactants are more stable than the products and the reaction is exothermic

the reactants are less stable than the products and the reaction is endothermic

the reactants are less stable than the products and the reaction is exothermic

the reactants are more stable than the products and the reaction is endothermic

in an exothermic reaction, the products have more energy than the reactants

in an exothermic reversible reaction, the activation energy of the forward reaction is greater than that of the reverse reaction

in an endothermic reversible reaction, the activation energy of the forward reaction is greater than that of the reverse reaction

in an endothermic reaction, the products are more stable than the reactants

the reaction is exothermic and the reactants have greater enthalpy than the products

the reaction is exothermic and the products have greater enthalpy than the reactants

the reaction is endothermic and the products have greater enthalpy than the reactants

the reaction is endothermic and the reactants have greater enthalpy than the products

temperature

volume

pressure

concentration

1 g cm^-3

24 dm³

298 K

4.18 J g^-1 K^-1