14. What is the total number of kilojoules of heat needed to change 150. G of ice to water at 0°C?

Explanation:

When water changes from ice (solid) to water (liquid), it is melting or fusion. Therefore, we can use the following formula to find energy:

where q is the energy, m is the mass, and Hf is the heat of fusion.

1. Define Values

The mass is 150 grams. The heat of fusion for water is 334 Joules per gram.

2. Calculate Energy

Substitute the values into the formula.

Multiply. Note that the grams (g) will cancel each other out and leave Joules as our units.

3. Convert Units

We found the answer in joules, but the question asks for kilojoules, so we must convert.

There are 1000 Joules in 1 kilojoule. Therefore, we can divide the joules calculated by 1000.

50.1 kilojoules are needed to change 150 grams of ice to water.

how to make a simple air condition

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.