In this deck, we'll explore some fundamental ideas in chemistry. You'll learn about the law of conservation of mass, how to calculate the relative formula mass of a compound, and why chemical equations need to be balanced. We'll also investigate why mass can sometimes appear to change during a reaction.

Let's start with a crucial rule in chemistry: the law of conservation of mass. This law states that during a chemical reaction, no atoms are lost or made. They are simply rearranged into new substances. This means the total mass of the substances you start with, called the reactants, must be exactly equal to the total mass of the substances you end up with, called the products.

Next, let's look at how to work out the mass of a compound. We use something called the relative formula mass, often written as M r, with a subscript r. To find it, you simply add up the relative atomic masses of all the atoms shown in the chemical formula. You can find the relative atomic masses for each element on the periodic table.