Question

The average ΔH_rxn for

MgO (s) + 2 HCl (aq) --> MgCl₂(aq) + H₂O (l) is -150. kJ/mol

What would be the ΔH_rxn for the following reaction:

MgCl₂(aq) + H₂O (l) --> MgO (s) + 2HCl (aq)

Group of answer choices

+300. kJ/mol

-150. kJ/mol

+150. kJ/mol

+75.0 kJ/mol

2.

The average ΔH_rxn for

Mg (s) + 2 HCl (aq) --> MgCl₂(aq) + H₂(g)

is -466 kJ/mol

What would be the ΔH_rxnfor the following reaction:

2 MgCl₂(aq) + 2 H₂(g) --> 2Mg (s) + 4HCl (aq)

Group of answer choices

+466 kJ/mol

+932 kJ/mol

-932 kJ/mol

-466 kJ/mol

3.

You dissolve 2.5 g of NH₄Cl in 50.0 g of water to prepare a solution with a specific heat of 4.08 J/(g°C).

As the solid dissolves, the temperature changes from 22.0°C to 17.5°C. What is q_sol?

(q_sol= m c  ΔT and ΔT = T_final – T_inital )

Group of answer choices

-0.964 kJ

-0.0459 kJ

+0.964 kJ

+0.0459 kJ

4.

If you dissolve 12.7 g of NaOH in water, in a coffee-cup calorimeter and determine that q_sol is +0.73 kJ, what would q_rxn be?

Group of answer choices

+0.73 kJ

+0.038 kJ

-0.73 kJ

-0.038 kJ

5.

When 7.5 g of NaOH is dissolved in water, q_rxn is -0.47 kJ. What is ΔH_rxn in kJ/mol for this reaction?

Group of answer choices

+2.5 kJ/mol

-0.0016 kJ/mol

-0.063 kJ/mol

-2.5 kJ/mol

Answer 1