in an experiment a student mixes a 50.0 ml sample of 0.100 m agno₃ (aq) with a 50.0 ml sample of 0.100 m nacl(aq) at 20.0°c in a coffee-cup calorimeter. which of the following is the enthalpy change of the precipitation reaction represented above if the final temperature of the mixture is 21.0°c? (assume that the total mass of the mixture is 100. g and that the specific heat capacity of the mixture is 4.2 j/(g.° (a) -84 kj/mol, (b) -0.42 kj/mol (c) 0.42 kj/molu (d) 84 kj/molpx

The enthalpy change during the reaction is -84 kJ/mole.

Explanation:

First we have to calculate the heat gained by the solution.

where,

Q = heat gained = ?

m = mass of the solution = 100.0 g

c = specific heat =

= final temperature =

= initial temperature =

Now put all the given values in the above formula, we get:

Now we have to calculate the enthalpy change during the reaction.

where,

= enthalpy change = ?

Q = heat gained = 420 J

n = number of moles silver nitrate= n

Molarity of the silver nitrate solution = M = 0.100 M

Volume of the silver nitrate solution = V = 50.0 mL = 0.050 L

(1 kJ = 1000 J)

Therefore, the enthalpy change during the reaction is -84 kJ/mole.