In a polystyrene calorimeter, 8.0 g of ammonium nitrate is placed in 50.0 ml of water. the initial temperature of the water is 22.9 °c. the temperature of the solution drops to 12.4 °c. assume the specific heat of the solution is 1.00 cal/g·°c. which of the statements below is true?
the reaction is endothermic with a heat of solution of approximately 609 cal/mol. the reaction is exothermic with a heat of solution of approximately 6.09 kcal/mol. the reaction is endothermic with a heat of solution of approximately 6.09 kcal/mol
the reaction is endothermic with a heat of solution of approximately 609 kcal/mol.

The reaction is endothermic with a heat of solution of approximately 6.09 kcal/mol

Explanation:

First of all we will calculate the number of moles of ammonium nitrate.

Number of moles = mass/ molar mass

Number of moles = 8.0 g/ 80.0 g/mol

Number of moles = 0.1 mol

Formula:

q₁ + q₂ = 0 (1)

q₂

q₂ = mcΔT

ΔT = 12.4°C - 22.9°C

ΔT = -10.5°C

m = 8 g + 50 g = 58 g

c = 1.0 cal/g.°C

q₂ = mcΔT

q₂ = 58 g × 1.0 cal/g.°C ×-10.5°C

q₂ = -609 cal

q₁

q₁ = nΔH(sol)

q₁ = 0.1 mol × ΔH(sol)

Now we will put the values of q₁  and q₂ in equation 1

q₁ + q₂ = 0

0.1 mol × ΔH(sol) + ( -609 cal) = 0

ΔH(sol)  = +609 cal / 0.1 mol

ΔH(sol)  = +6090 cal/mol

cal to kcal

6090/1000

ΔH(sol)  = +6.09 kcal/mol

asking the goog might u get an answer

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e