# What is the mass of #9.25 times 10^22# molecules of water?

##### 2 Answers

27.72g

#### Explanation:

A mole of any compound has a mass equal to the compound's relative formula mass in grams.

So, the first step is to work out how many moles of the substance there is.

There are

So we have 1.54 moles of water.

Next, we need to find the relative formula mass of water using the relative atomic masses of the atoms making it up. Water is

Now we remember the rule about moles and multiply 18 by our 1.54 moles to get 27.72g (27.7 to 3SF)

Hope this helps; let me know if I can do anything else:)

#### Explanation:

The relationship between the number of particles and the number of mole of a substance is given by the equation

Let's substitute the definition of

Then, let's substitute the value of

Now, let's evaluate the molar mass of water:

Substituting into the equation:

Dividing both sides of the equation by

Multiplying both sides by

Therefore, the mass of