15 April, 20:29

# Ammonium nitrate dissociates in water according to the following equation:43 () = 4 + () + 03 - ()When a student mixes 5.00 g of NH4NO3 with 50.0 mL of water in a coffee-cup calorimeter, the temperature of the resultant solution decreases from 22.0 °C to 16.5 °C. Assume the density of water is 1.00 g/ml and the specific heat capacity of the resultant solution is 4.18 J/g·°C.1) Calculate q for the reaction. You must show your work.2) Calculate the number of moles of NH4NO3 (s) which reacted. You must show your work.3) Calculate ΔH for the reaction in kJ/mol. You must show your work.

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1. 15 April, 20:52
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NH₄NO₃ = NH₄⁺ + NO₃⁻

heat released by water = msΔ T

m is mass, s is specific heat and ΔT is fall in temperature

= 50 x 4.18 x (22 - 16.5) (mass of 50 mL is 50 g)

= 1149.5 J.

This heat will be absorbed by the reaction above.

q for the reaction = + 1149.5 J

2)

molecular weight of NH₄NO₃ = 80

No of moles reacted = 5/80 = 1 / 16 moles.

3)

5 g absorbs 1149.5 J

80 g absorbs 1149.5 x 16 J

= 18392 J

= 18.392 kJ.

= + 18.392 kJ

ΔH = 18.392 kJ / mol