A. How many calories are needed to raise the temperature of 1 gram of water by 1 °C?

B. How many calories are needed to melt 1 gram of ice at 0 °C?

C. How many calories are needed to vaporize 1 gram of boiling water at 100 °C?

A) 1 cal

B) 80 cal

C) 540 cal

Explanation:

A)

The amount of heat energy needed to raise the temperature of a certain mass of a substance is given by

where

m is the mass of the substance

C is the specific heat capacity

is the change in temperature

In this problem:

m = 1 g is the mass of water

is  the specific heat capacity of water

is the change in temperature

So, the heat needed is

B)

For a solid substance at its melting point, the amount of heat needed to melt completely the substance is given by

where

m is the mass of the substance

is the specific latent heat of fusion of the substance

In this problem:

- The ice is already at melting point, 0 °C

- Mass of the ice:

- Specific latent heat of fusion of ice:

So, the heat needed is

C)

For a liquid substance at its boiling point, the amount of heat needed to boil completely the substance is given by

where

m is the mass of the substance

is the specific latent heat of vaporization of the substance

In this problem:

- The water is already at boiling point, 100 °C

- Mass of the water:

- Specific latent heat of vaporization of water:

So, the heat needed is

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles