Is my thinking correct? Have I used the correct equations? Thank you Question: Y

Question

Is my thinking correct? Have I used the correct equations? Thank you
Question:
You wish to find the enthalpy of reaction per mole of nitric acid for the following reaction:

Mg (s) + 2HNO3 (aq) --> Mg(NO3)2 (aq) + H2 (g).

At 25 degrees C, you add 0.050 grams of magnesium flakes to a makeshift coffee-cup calorimeter (Ccal= 11 Joules/C) that contains 100.0 mL of 1.25M HNO3. You close the top and monitor the temperature of the solution until it stabilizes at 27.25 degrees C. Assume the density of the solution is 1.01 g/mL and that the specific heat is 4.22 J/(g*°C).

a) What constitutes the system in this experiment?

My answer: Everything INSIDE the coffee-cup calorimeter.

b) WHat constitutes the surroundings in this experiment?

My answer: Everything OUTside the coffee-cup calorimeter

c) How are the heat of reaction and the heat of the surroundings related?

My answer: Heat gained or lost from the system is proportional to the heat gained or lost from the surroundings.

d) Calculate the heat gained or lost by the calorimeter?

My work:

(11 J/°C)*(27.25°C-25°C) = 24.75 joules?

e) Calculate the heat gained or lost by the solution?

My work:

(101 grams soln)*(4.184 J/g*°C)*(27.25°C-25°C) = 950.8 joules?

f) Calculate the heat gained or lost by the reaction?

My thoughts: I'm assuming because my answers to question a, b, and c, that energy gained/lost from the calorimeter is the energy gained or lost by the reaction. Is my thinking correct?
...If so, then the heat gained or lost by the reaction is equal to -24.75 joules

g) Calculate the enthalpy of reaction per mole of nitric acid?

My work:

(0.050 g Mg (solid))*(1 mol Mg/24.3050 g Mg)*(2 mol HNO3/1 mol Mg)= .411 moles HNO3 -> .9508 kJ/.411 moles =  2.31 kJ/mol HNO3

So that's it, if your wondering what I'm asking/looking for is simply confirmation that my thinking is correct and I'm doing the problems correctly. Thank you in advance.

Explanation / Answer

a)

your thinking is wrong

Actual

The substance which is undergoing physical and chemical change

Therefore,

mg(s) + HNO3(aq) is called system

b)

your thiging is wrong

Actual

Components that serve to either provide heat to the system or absorb heat from system is called surroundings

Heat is absorbed by solution + coloriemeter

Therefore,

system is solution + caloriemeter

c)

your thinging is correct

d)

your thinging is correct

e)

your thinging is correct

f)

your thinging is wrong

Actual

Heat lost or gained by the system = - (heat gained or lost by bsurrondings)

therefore,

Heat lost by reaction = - (heat gained by solution + heat gained by calorimeter)

Heat lost by reaction = - (950.8J + 24.75J)

Heat lost by reaction = - 975.55J

g)

your mole calculation of HNO3 is correct but your result is not correct as your result of heat evolved by reaction is not correct

Actual

No of moles of HNO3 = (1.25mol/1000ml)×100ml = 0.125mol

No of moles of Mg = (0.050g/24.305g/mol) = 0.002057

Mg is limiting reagent

0.002057moles of Mg react with 0.004114moles of HNO3

therefore,

enthalphy of reaction per mole of HNO3 = (-975.55J/0.04114mol)×1mol = - 23.71kJ/mol

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