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Flashcards in F321: Calculations Deck (11)
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0
Q

Relative isotopic mass

A

The mass of an atom of an isotope compared to 1/12th the mass of carbon-12. (on a scale where 12 is exactly 12)

1
Q

Isotope

A

Atoms with the same number of protons but a different number of neutrons (same e- arrangements so same chemical properties)

2
Q

Relative atomic mass

A

Average mass if an atom of an element compared to 1/12th the mass of carbon-12

3
Q

Calculating Ar

A

From the mass and relative abundance of all the isotopes
Eg. for 75% 35Cl and 25% 37 Cl
(75x35)+(25x37)/100 = 35.5

4
Q

Calculating Mr and RFM

A

Add up individual relative atomic masses

5
Q

Mole

A

The amount of a substance which contains as many particles as there are atoms in 12g of Carbon-12

6
Q

Avogadro’s constant

A

The number of particles in one mole of a substance’ 6.02x10^23

7
Q

Working out empirical formula

A
Divide masses (or %) by Ar to work out ratio of moles, divide all by the smallest number to give a whole number ratio
(Look out for halves- double values if so)
8
Q

Working out the molecular formula

A

Compare Mr of empirical formula with the Mr given for the molecule. Multiply by a certain factor to make them the same.

9
Q

Concentration

A

A measure of the number of moles of a solute dissolved per dm3 of solvent

10
Q

Stoichiometry

A

Molar ratios

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