# Help!!!!

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hey: to do this question you need to follow these steps:

we will start from the first one

-First you need a **formula for Mole**. It would be easier if you use a **formula triangle** like this one

OK...so since we are **working out the mole of H2 molecule**, we **cover the mole on the triangle** (the blue part)

This leaves us with: **Mass (g) / Atomic mass **

Looking back on the question we need to find the **Mass of H2 molecule and the Atomic mass of H2 molecule**

**Mass of H2 molecule given= 4g**

**Atomic No of H2 molecule...**.

-H2 is a molecule so this means that you need to find the Atomic no of H atom then times by 2 (since its H2 molecule NOT AN ATOM ON ITS OWN)

**Mass of 1 H atom =1 (given in the periodic table)**

** theorfore 1 x 2 = 2**

**Now plug in the numbers in the formula given **

**-Mass (g)****/ Atomic mass **

**-4g/2 = 2 mol **

**therfore in 4g of H2 molecule there is 2 moles of it...**

**-i guess this is the answer...im rusty when it comes to maths in chemistry**

For the second question you are working out the ATOMS INVOLVED so you need to find the atomic number of the atoms only

Hope this was useful