Q. 25

Expert-verified
Found in: Page 544

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A 65 cm3 block of iron is removed from an 800C furnace andimmediately dropped into 200 mL of 20C water. What fractionof the water boils away?

21% of the watere boils away.

See the step by step solution

## Step 1: Applicable formulas on the problem

The specific heat and the latent of the vaporisation are given per mass.

Knowing the eaquation

, the quantities of iron and water have to be converted to mass from volume and is the mass densty in the equation.

Known factors:

The density of water, , and

the density of Iron, .

Given informations,

This experiment is done because one of the following three will happen after the iron ot water,

(1) The boiling point of the water will be greater than the Equilibrium temperature, in which no water will have boiled.

(2) The boiling point of the water and the equilibrium temperature will be equal.

(3) The boiling point of the water will be less than the equilibrium point of the water.

Let's assume that the 2nd case will happen. The entire water will be at the boiling point ny taking some energy from the hot iron. The rest energy from the hot iron will evaporate X part of the total mass() of the water.

## Step 2: Finding of the asked ratio

Putting all the numerical values to get the value of X,

Approximating and taking the ratio in percentage, the final answer will be,