Question

In a different experiment, the student uses a calorimeter which is perfectly insulated. She fills the calorimeter with 100.0 g of 25.00°C dilute HCl solution and adds 0.594 g Mg metal (24.3 g/mol). The final temperature of the apparatus comes to 41.83°C. Remember, the solution is made-up of the solute and the solvent. The specific heat for magnesium is negligible compared to the aqueous solution. What is the Molar Heat of Enthalpy for this reaction?

Answer 1

Step-by-step explanation:

Mg + 2HCl = Mg Cl₂ + H₂

.594 g = .594 / 24.3

= .02444 mole

Heat evolved = msΔ T , m is mass of water ( solvant ) , s is specific heat of water , Δ T is rise in temperature

= 100 x 4.2 x ( 41.83 - 25 )

= 7068.6 J

.02444 mole of Mg evolves 7068.6 J of heat

1 mole of Mg evolves 7068.6 /.02444 J

= 289222.6 J

= 289 kJ .

Molar heat enthalpy = 289 kJ .