Zinc metal reacts with hydrochloric acid according to the balanced equation:

When 0.103 g of Zn( s ) is combined with enough HCl to make 50.0 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 0C to 23.7 0C. Find ΔHrxn for this reaction as written. (Use 1.0 g/mLfor the density of the solution and as the specific heat capacity.)

Solution 75E: Step 1 of 5 In general, the heat (q) required to raise the temperature of a sample is obtained by multiplying the heat capacity of the substance (C ) with mass of se substance (m) and temperature change (T) as given below: q = C ms .......... (1) Step 2 of 5 Volume of the solution = 50.0 mL Density of the solution = 1.0g/mL Mass of 50.0 mL solution (m) is: 50.0 mL×(1.0g÷mL) = 50g Specific heat capacity of solution is 4.18 J/g. C 0 Initial temperature(T) of soluion = 22.5 C 0 0 Final temperature (T) of solutfn = 23.7 C The change in temperature (T) = T - T = 23.7 C – 22.5 C = 1.2 C0 0 0 f i Step 3 of 5 Substituting the values of m, C and T in eqstion 1, we can get the amount of heat required to 0 0 raise the temperature of the solution from 22.5 C to 23.7 C is: q = C mT = 50g×(4.18 J ÷g×C)×1.2C = 2.5×10² J soln s 0 Therefore, the amount of heat (q ) added to chasolnhe temperature of the solution from 22.5 C to 23.7 C is 2.5x10 J. 2