C2 - Mass, Moles & Analysis Flashcards
What is the mass number of an atom?
The number of protons and neutrons in the nucleus.
What is the atomic number of an atom?
The number of protons an atom has.
What are isotopes?
Atoms with different numbers of neutrons.
What is the relative mass of a proton and neutron?
1
What is the relative mass of an electron?
1/1836
What is the relative formula mass of a compound?
The sum of the relative atomic mass of all of the atoms.
What is the mass of a mole of carbon, oxygen and iron?
- 12g
- 16g
- 56g
How is the percentage mass of an element in a compound found?
(mass of element / total mass of compound) x 100
How is the empirical formula found?
Simplest ratio of moles.
How is the number of moles of an element in a compound found?
mass of the element / relative atomic mass
What is the yield of a chemical reaction?
How much product was made.
How is percentage yield calculated?
(amount produced / maximum amount possible) x 100
Give five reasons why yield is rarely 100%.
- The reaction may be reversible.
- Some reactants may give unexpected products.
- The product may be lost in the apparatus.
- The reactants may not be completely pure.
- It may be difficult to separate products.
Why is it important to maximise yield?
- In order to produce less waste.
- Reduce energy usage.
- Conserve limited resources.
- Reduces pollution.
What is a reversible reaction?
The products of the reaction can react to make the original reactants.