0.5 g of ca is added to 50 ml of 1.0 m hcl. once reaction is complete, the temperature of the solution has risen from 25.2 c to 71.4 c.
a. calculate the heat gained by the solution.
b. heat lost by the reaction
c. calculate the heat of reacton.
i've gotten several answers and i think i am overthinking the question. i am having trouble finding the correct mass to use.

Let us assume that the solution has the same specific heat capacity as water, of 4.18 Joules per gram.

a) H = mCpΔT
Where m will be the mass of the solution. We do not incorporate the mass of Ca because it will dissolve and release some amount of Hydrogen gas; rendering its contribution negligible. Assuming solution density equal to water's 1 gram per cubic centimeter:
H = 50 x 4.18 x (71.4 - 25.2)
H = 9655.8 Joules are gained

b) Assuming no heat is lost to the surroundings,
Heat lost by reaction = Heat gained by soluton
Heat lost by reaction = 9655.8 Joules

c) Moles of Ca present = 0.5/40 = 0.0125
Heat of reaction is the energy released upon reaction of the quantities in the balanced equation of a reaction. In this case:
Ca + 2HCl → CaCl₂ + H₂
So 0.0125 moles produces 9655.8 Joules
1 mole will produce: 9655.8 / 0.0125
= 772.5 kJ

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.

The answer is celsius