How do you work out of the chemical formula if you need to add 3 elements? eg: potassium hydrogen sulphate = KHSO4
The secret to working out a chemical formula for a more complex chemical than two simple ions (like NaCl) is to always make sure the charges of the individual ions add up to the charge of the product compound (usually 0). In the case of KHSO4, we can start with what we know and work from there. SO4-- is the sulfate anion and it has a negative 2 charge. So we need to have 2 positive charges to even out to a neutral chemical with no net charge. We know that a hydrogen proton (H+) has a plus 1 charge and the potassium ion (K+) also has a plus 1 charge. This is 1+1+(-2)=0. So the charges work out and we get potassium hydrogen sulfate (KHSO4).
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