When 1.008 g of hydrogen reacts with chlorine in a calorimeter containing 500.00 g water, the temperature rises from 25.00 °C to 29.24 °C. Calculate water for the process. (Remember,
change in T determines (1) the number of significant digits and (2) the sign of your
answer.)
H2(g) + Cl2(9) --> 2HCl(g)
A) -8.870 kJ
B) +8870 J
C) -8870 J
D) +8.870 kJ

The heat released by reaction : C) -8870 J

Given

1.008 g of hydrogen

500.00 g water

The temperature rises 25.00 °C to 29.24 °C

Required

energy required

Solution

Q absorbed by water :

Q = m.c.Δt

Q = 500 g x 4.18 J/g C x (29.24-25)

Q = 8870.08 J

The reaction to produce HCl is an exothermic reaction (releasing heat), so that Q is negative

Q water = -Q HCl = -8870.08 J