A 2.50 g sample of zinc is heated, and then placed in a calorimeter containing 65.0 g of water. Temperature of water increases from 20.00 oC to 22.50 oC. The specific heat of zinc is 0.390 J/g oC. Assuming no heat loss, what was the initial temperature of the zinc metal sample?

The initial temperature of the zinc metal is  720 ° C

Explanation:

Given data,

Zn

m=2.50 g            

C=0.390 J/g° C

ΔT= (22.50° C- Ti)

H2O

m= 65.0 g

C= 4.184 J/ g° C

ΔT = 2.50° C

We have the formula,

qH20= - qZn

(65.0 g) (4.184 J/ g° C) (ΔT 2.50° C)=(2.50 g) ( 0.390 J/g° C) (ΔT 22.50° C- Ti)

solving the equation we get,

697.3 ° C=- 22.50 ° C+Ti

Ti= 720 ° C

The initial temperature of the zinc metal is  720 ° C

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.