1. Find the relative Atomic Mass (Ar) for the following elements.

2. Find the relative formula mass (Mr) for the following compounds.

- H2O
- H2SO4
**CaCO3**
**MgO**
**Na2CO3**
**Mg(NO3)2**
**FeCl3**
**CH3COOH**
**H3PO4**
**C6H8O7**
**KNO3**

**2. Find the percentage of oxygen in the following compounds. Which compound has the greatest percentage
of oxygen? **

**3. Find the percentage of carbon in the following compounds. Which compound has the least percentage
of carbon?**

**4. Sebastian needs to make 20 g of ZnCl2. He knows he can make ZnCl2 by reacting Zn with HCl acid.**

** Zn + HCl --> ZnCl2 + H2**

**Determine the relative atomic masses and the relative formula masses for the reactants and the products.**
**Determine the ratio of Zn to ZnCl2**
**Determine the ratio of HCl to ZnCl2**
**Determine how much Zn and HCl you need to form 20 g of ZnCl2.**

**5. Jane wants to make 100 g of Hg. To do this she is going to heat HgO to form Hg and O2.**

**What type of reaction is this?**
**Balance the equation**

** HgO --> Hg + O2**

**Determine the relative formula and relative atomic masses of the reactants and of the products.**
**Determine the ratio of HgO to Hg**
**Determine how much HgO Jane needs to heat to form 100g of Hg.**