Amount of Substance

Question 0

Equation to find the number of moles?

Answer 0

n = mass / mr
Moles = Mass / Mr
mass in g

Question 1

One mole is equal to… (Avogadro’s Constant, L)

Answer 1

6.023 x 10^23

Question 2

Grams (g) to Kilograms (Kg)?

Answer 2

Divide by 1000.

Question 3

cm^3 to dm^3.

Answer 3

Divide by 1000.

Question 4

dm^3 to m^3.

Answer 4

Divide by 1000.

Question 5

cm^3 to m^3.

Answer 5

Divide by 1000000.

Question 6

Equation to find the mass?

Answer 6

Mass = Moles x Mr
Mass = n x Mr

Question 7

Percentage Yield Equation?

Answer 7

% Yield = Actual Yield / Theoretical Yield x 100

Question 8

Percentage Atom Economy Equation?

Answer 8

% Atom Economy = Mass of desired product / Total mass of reactants x 100

Question 9

Standard pressure?

Answer 9

100kPa (1 atm)

Question 10

Standard temperature?

Answer 10

273K (0 Degrees Celsius)

Question 11

Gaseous Moles Equation?

Answer 11

n = v(cm^3) / 24000

or

n = v(dm^3) / 24

Question 12

Calculating volumes of gases in equations? (Definition)

Answer 12

1 mole of any gas occupies 22.4dm^3 at standard temperature and pressure.

Question 13

Molarity/Concentration Equation?

Answer 13

n = MV(cm^3) / 1000
Moles = Molarity x Volume / 1000
M = n x 1000 / V(cm^3) 
Molarity = Moles x 1000 / Volume

Question 14

The Ideal Gas Equation?

Answer 14

pV = nRT
p = pressure in Pa
V = volume in m^3
n = number of moles
R = the gas constant 8.31JK(-1) mol (-1)
T = temperature in K

Question 15

kPa to Pa?

Answer 15

Multiply by 1000.

Question 16

Degree Celsius to Kelvin?

Answer 16

Add 273

Question 17

Concentration/Molarity is measured in…

Answer 17

mol dm^3

Question 18

State Symbol s is…

Answer 18

Solid.

Question 19

State Symbol g is…

Answer 19

Gas.

Question 20

State Symbol aq is…

Answer 20

Aqueous (solution in water).

Question 21

What are Titrations used for?

Answer 21

Titrations are used to find out the concentration of an acid or an alkali.

Question 22

State Symbol l is…

Answer 22

Liquid.

Question 23

Titration needs… (4)

Answer 23

• A standard solution with an accurately known concentration.
• A graduated burette to deliver precise volumes of one of the solutions.
• A conical flask to hold a precise volume of the other solution, measured using a transfer pipette.
• An indicator.

Question 24

What is a Titre?

Answer 24

The volume of titrant needed to react completely with the reagent in the flask.

Question 25

What is Empirical Formula?

Answer 25

The empirical formula of a compound gives the simplest ratio of the number of atoms of each element in a molecule/entity.

Question 26

What is Molecular Formula?

Answer 26

The molecular formula of a compound gives the actual number of atoms of each element in a molecule/entity.

Question 27

What is Atom Economy?

Answer 27

Atom Economy is a measure of the proportion of reactant atoms that become part of the desired product in the balanced chemical equation.

Question 28

What is Theoretical Yield?

Answer 28

The mass of product that should be formed in a chemical reaction.

Question 29

Bromomethane is reacted with Sodium Hydroxide to make Methanol: CH3Br + NaOH > CH3OH + NaBr Calculate the atom economy of this reaction.

Answer 29

23.7%

Question 30

Calculate the amount, in moles, of TiCl4 in 165g.

Answer 30

``` Moles = Mass / Mr n = 165 / 189.9 n = 0.87 moles ```

Question 31

A sample of Magnesium Nitrate decomposed to produce 0.402 mol of gas. Calculate the volume, in dm^3, that this gas would occupy at 333K and 1.00 x 10^5. (The gas constant R = 8.31 JK(-1) mol (-1) )

Answer 31

``` pV = nRT p = 100000 Pa V = ? n = 0.402 mol R = 8.31 JK(-1) mol (-1) T = 333 K ``` ``` 100000 x V = 0.402 x 8.31 x 333 100000 x V = 1112.42646 1112.42646 / 100000 = V V = 0.0111 m^3 m^3 > dm^3 = Multiply by 1000. 0.0111 x 1000 = 11.1 11.1 dm^3 ```

Question 32

An oxide of Nitrogen contains 25.9% by mass of Nitrogen. Determine the empirical formula of this oxide.

Answer 32

N O 25. 9 74.1 25. 9/14 74.1/16 1. 85 4.631 4. 631 / 1.85 = 2.5 (x2) 2: 5 N2O5

Question 33

Suggest one possible danger when a metal carbonate is reached with an acid in a sealed flask.

Answer 33

An explosion = Glass breaks.

Question 34

A solution containing 0.732 mol of Ammonia was made up to 250cm^3 in a volumetric flask by adding water. Calculate the concentration of Ammonia in this final solution and state the appropriate units.

Answer 34

Molarity = Moles x 1000/V(cm^3) M = 0.732 x 1000 / 250 M = 2.93 2.93 mol dm(-3)

Question 35

The reaction of Magnesium Nitride, Mg3N2, with water produced Ammonia and Magnesium Hydroxide. Write an equation for this reaction.

Answer 35

Mg3N2 + 6H2O = 2NH3 + 3Mg(OH)2

Question 36

The amount of substance that contains 6.022 x 10^23 particles is called...

Answer 36

A mole.

Question 37

The definition of the Avogadro constant is...

Answer 37

The number of atoms in 12g of Carbon - 12.

Question 38

Boyle's Law?

Answer 38

The product of pressure and volume is a constant as long as the temperature remains constant.

Question 39

Boyle's Law Equation?

Answer 39

PV = constant.

Question 40

Charles' Law Equation?

Answer 40

V ~ T and V/T = constant.

Question 41

Charles' Law?

Answer 41

The volume is proportional to the temperature as long as the pressure remains constant.

Question 42

Gay-Lussac's Law Equation? (Constant volume law)

Answer 42

P ~ T and P/T = constant. Combining these relationships gives us the equation: PV/T = constant for a fixed mass of gas

Question 43

Gay-Lussac's Law? (Constant volume law)

Answer 43

The pressure is proportional to the temperature as long as the volume remains constant.

Question 44

2 mol dm(-3) means...

Answer 44

There are 2 moles of solute per cubic decimetre of solution.

Question 45

1 decimetre is...

Answer 45

10cm.

Question 46

One cubic decimetre, 1dm^3 is...

Answer 46

1000cm^3.

Question 47

What is ibuprofen?

Answer 47

A mild painkiller and anti-inflammatory drug.