Basics Flashcards
What do subscript numbers show in a formula?
Shows the number of atoms of that element in a compound
What are coefficients?
The numbers in front of atoms or molecules in an equation.
They show the ratio of the different types of particles that are involved in a reaction or chemical reaction
Why is not having balanced equations a problem?
In a chemical reaction, atoms are never gained or lost.
What is a mole?
6.022 x 10^{23} molecules
What does it mean by ‘1 mole of oxygen molecules’?
1 mole of oxygen molecules = 6.022 x 10^{23} molecules of oxygen
What is the mole ratio of a reaction?
The ratio between the number of moles of the substances of that reaction.
In the following reaction, if 6 moles of water is produced, how much oxygen reacted?
O2 + 2H2 -> 2H2O
3 moles of oxygen reacted
What does the equation N2 + 3H2 -> 2NH3 tell us about the mole ratios of nitrogen to hydrogen?
For every one mole of N2 that reacts, 3 moles of H2 reacts.
How do we find out the amount of other substances in a reaction using mole ratios?
If we’re told how much of one substance was involved in a reaction, we can use the mole ratio from the balanced equation , to tell us the amount of all of the other substances.
How would you work out the moles of A, if you have the moles of B and a balanced equation?
Moles of A = Moles of B x Coefficient of A / Coefficient of B
What is the limiting reactant?
The reactant that is completely used up first.
It limits the number of particles of the other substances that can react.
When is a substance in excess?
When there is more than enough of it to fully react with the other reactants.
What equation links moles, number of particles and the Avogadro constant?
Moles = Number of particles / Avogadro constant
