C2.3 - Atomic Structure, Analysis And Quantitative Chemistry Flashcards
1
Q
What is one mole of a substance?
A
The Ar or Mr of that substance in grams.
2
Q
How do you find the number of moles of each element in a compound?
A
Mass of element/Mr of compound.
3
Q
What is the Ar relative to?
A
The C12 isotope.
4
Q
What is the Ar?
A
An average value for the mass of one atom of an element.
5
Q
How do you find the Mr of a compound?
A
Summing the relative atomic masses of the elements in the compound.
6
Q
How do you find the percentage of an element in a compound?
A
Ar x number of atoms/Mr of compound
7
Q
How do you find the empirical formula of a compound? (4)
A
- List the elements in the compound.
- Write the mass of that element in the experiment.
- Divide by the Ar.
- Find the ratio between the values.
8
Q
Why might a reaction not produce optimum yield? (3)
A
- The reaction is reversible.
- The reactants may react differently from the expected reaction.
- Some of the product may be lost when it is separated from the reaction mixture.
9
Q
How do you calculate percentage yield?
A
Actual yield/Potential yield
10
Q
What is the mass number?
A
The total number of neutrons and protons in an element.
