A 7.5 gram sample of zinc (specific heat = 0.390 J/g°C) is heated and then placed in a calorimeter containing 65.0 grams of water. The temperature of water increases from 20.00°C to 25.00°C. What was the initial temperature of the zinc?

489.88 was the initial temperature of the zinc.

Explanation:

Given:

mass of zinc = 7.5 grams

mass of water = 65 grams

specific heat = 0.390J/g°C

specific heat of water = 4.184 J/g°C

initial temperature of water = 20 degrees

Final temperature of zinc and water will be same as zinc is dissolved in water thus T2zinc and T2 water = 25 degrees

ΔTzinc = change in temperature T2 - T1

initial temperature of zinc = ?

The formula used is

q = mcΔT for both water and zinc

putting the values for zinc and water in the formula:

mzinc x czinc x T2 zinc - T1 zinc = mwater x c water x T2 water - T 1 water

7.5 x 0.390 x ΔT zinc = - (65 x 4.184 x (25-20)

2.925 x ΔT zinc = - 1359.8

ΔT zinc = - 464.88 degrees

Now,

ΔT zinc = T2 zinc - T1 zinc

T1 zinc = - 464.88-20

=489.88 degrees

489.88 degrees is the initial temperature of the zinc.