How many calories are given off by 85 g of water that cools from 90 c to 67 c ?

             Q  =  - 1.95 kCal

Solution:

The equation used for this problem is as follow,

                                                  Q  =  m Cp ΔT

Where'
            Q  =  Heat  =  ?

            m  =  mass  =  85 g

            Cp  =  Specific Heat Capacity  =  4.18 J.g⁻¹.°C⁻¹

            ΔT  =  Change in Temperature  =  67 °C - 90 °C  =  - 23 °C

Putting values in eq. 1,

                             Q  =  85 g × 4.18 J.g⁻¹.°C⁻¹ ×  - 23 °C

                             Q  =  - 8172 J

                             Q  =  - 1.95 kCal

Answer) by studying proton collisions hope this : )