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?

Question

Chemistry

Lilliana Massey

20 January, 07:39

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?

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Sergio Hull · Answer 1

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.