Redox, Stoichiometry

Question 1

Oxidant

Answer 1

Electron acceptor

Is reduced, becomes more negative

Question 2

Reductant

Answer 2

Electron donor
Is oxidised
Charge becomes more positive

Question 3

% atom in compound by mass

Answer 3

(# atoms in compound x M(atom)) / M(compound)

Question 4

Finding empirical formula from combustion data

Answer 4

Hydrocarbon - the only source of C in the CO2 released, and H for H2O

Note 2H per H2O

m(O) from mass difference if the compound has O

Question 5

Hydrates define

Answer 5

Ionic solid with water of crystallisation - stable until heated above 100*C

Question 6

Mass ionic hydrates is equal to

Answer 6

Mass ionic compound + mass water

Question 7

Titration method with protons

Answer 7

n(H+) donated by acids = n(H+) accepted by bases

Question 8

Concordat titre

Answer 8

Within 0.1mL of each other

Question 9

ppm and ppb

Answer 9

Parts per million or billion

Alternative for concentrations

Question 10

Converting between %, ppm and ppb

Answer 10

Write as a fraction, multiply both top and bottom by an appropriate factor to get desired 10^2, 10^6 or 10^9 in the denominator.

Question 11

Method with gL^-1

Answer 11

Use density to convert mass to volume.

Question 12

ppm and ppb alternate units

Answer 12

mgL^-1 = ppm 
μgL^-1 = ppb

Question 13

Mass percent

Answer 13

Mass SOLUTE / mass Solution

Question 14

Density

Answer 14

Mass solution / volume solution

Question 15

molL-1

Answer 15

Moles of solute / volume of solution

Question 16

Molal

Answer 16

Amount in moles of SOLUTE / mass of SOLVENT

Question 17

Molality definition

Answer 17

Amount of solute (mol) per kg of solvent

Mass solution = mass solvent + mass solute