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Flashcards in Calculations Deck (13)
1

moles =

mass(g)/Mr

2

% yield =

actual amount/expected amount x 100

3

Q (energy change) (J) =

m(g) x C (4.2) x DeltaT

4

DeltaH (molar enthalpy change) (kJ/mol)=

-Q/mols

5

Concentration (moldm-3) =

mols/volume(dm3)

6

Charge (C) =

current (A) x time (s)

7

mols of e- =

charge (C)/96500

8

96500C =

1 faraday = 1 mol of electrons

9

Relative atomic mass (Ar) =

SUM(isotope mass x isotope abundance) / 100

10

Relative formula mass (Mr) =

SUMAr

11

How to work out empirical formula

Divide each element by their relative atomic mass
Divide by the smallest number of mols

12

Energy change (can be Q or DeltaH) =

SUM(bonds broken) - SUM(bonds made)

13

volume of a gas (dm3) =

mols of gas x 24