1. Chemical Quantities Imagine you had the following: 7g of lithium 12g of diamonds 28g of aluminium 80g of bromine 197g of gold Which one do you have the highest amount of?

2. Do all atoms have the same mass? Chemical Quantities The relative mass compares the masses of atoms to each other - it gives us a ratio. For example, consider hydrogen, carbon and oxygen. Relative masses: H = 1 C = 12 O = 16 This means that one carbon atom is 12x heavier than one hydrogen atom. How many times heavier than one hydrogen atom is one oxygen atom?

3. Since we have a ratio, we can scale up each element by the same amount. Chemical Quantities 100 carbon atoms are 12x heavier than 100 hydrogen atoms. What if we had enough hydrogen atoms to make 1 gram of hydrogen? How many times heavier than 100 hydrogen atoms are 100 oxygen atoms? How much would the same number of carbon atoms weigh? And the same number of oxygen atoms? So, there are the same number of atoms in 1 gram of hydrogen as there are in 12 grams of carbon.

4. Chemical Quantities 1 gram of hydrogen, 12 grams of carbon and 16 grams of oxygen are the same amounts. They each contain the same number of molecules. Dozen This number of molecules is 6.022 x 10 23. It is given the name a 'mole'. One mole of atoms is 6.022 x 10 23 atoms. 12 Score Gross Mole 20 144 6.022x10 23 So the relative mass is the same number as the molar mass, just with different units. Oxygen has a relative mass of 16 and molar mass of 16 g/mol

5. Chemical Quantities Imagine you had the following: 7g of lithium 12g of diamonds 28g of aluminium 80g of bromine 197g of gold Which one do you have the highest amount of? Which one is there the least of?