Flashcards in C2.3 How Much? Deck (15):
What is the relative mass of a proton?
What is the relative mass of a neutron?
What is the relative mass of an electron?
What does the mass number mean?
The number of protons + the number of neutrons
What is an isotope?
Atoms with the same number of protons and electrons but different number of neutrons
What is relative atomic mass?
The mass of an atom compared to 1/12 of an atom of carbon-12
What is relative atomic mass measured in?
What is the relative formula mass (Mr) of CO2
12 + 16 + 16 = 44
What is the relative formula mass (Mr) of MgO?
24 + 16 = 40
What is the percentage by mass of magnesium in magnesium oxide?
24 / 40 x 100 = 60%
Give two benefits of using instrumental methods such as gas chromatography?
Can detect small samples
Give two disadvantages of using instrumental methods such as gas chromatography?
Require specialist training to interpret
Can only identify samples by comparing with data of known substances
In what part is the relative molecular mass of a substance measured?
The mass spectrometer
What is the retention time?
The time from when a substance enters a gas chromatogram, to when it leaves.