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Chemistry A Level > The Mole > Flashcards

Flashcards in The Mole Deck (23):
1

What is an "Amount"

A quantity of a substance in moles

2

What is a mole?

The number of atoms in 12g of C12 = 6.02x10 ^23

3

What is the avagadro constant?

6.02x10 ^23

4

What is "Molar mass"

The mass per mole of a substance (gmol^-1)

5

What is empirical formula and how do you calculate it?

The simplest whole number ratio of atoms in a compound.
1. Write the masses / percentages of each element
2. Write the molar masses of each
3. Write the number of moles of each you have
4. Divide all of the numbers of moles by the smallest one
5. Round to nearest whole numbers

6

What is the calculation linking moles, molar mass and mass

Moles = Mass / Molar mass

7

What is the molecular formula and how do you calculate it using the empirical formula?

Formula that shows the number and type of atoms of each element present in a molecule.
Divide the known Mr of the formula by the Mr of the empirical formula.

8

What do:
a) Anhydrous
b) Hydrated
c) Water of crystallisation
Mean?

a) A crystalline compound containing no water molecules
b) A crystalline compound containing water molecules
c) Water molecules bonded into a crystalline structure

9

How do you calculate percentage error of a calculation?

Percentage error = Total uncertainty / Value measured X 100

10

What is total uncertainty?

The ability of a piece of equipment to only measure to certain amount of D.P., thus we cannot be sure past that decimal place.

11

What does EMMA stand for when it comes to reacting masses?

Equation
Moles (total)
Moles (Used) Answer

12

What is a solute?

Something to be dissolved

13

What is a solvent?

Something that causes a solute to dissolve

14

What is a solution?

A solute having dissolved in a solvent.

15

What is a standard solution?

A solution containing a precisely known concentration of a substance.

16

What equation links number of moles, Concentration and volume?

Moles = Concentration x Volume

17

What is volume measured in?

dm^3

18

What do you do in titration calculations when you have 3 concordant values?

Take an average of all 3

19

What is the general volume of one mole of gas at room temperature and pressure (r.t.p.)?
As such, how do you calculate number of moles of gas given volume or vice versa?

24.

Number of moles = volume/24
Volume= Number of moles x 24

20

What is the ideal gases equation and what does each part of it mean?

P x V = n x R x T
P= Pressure
V= Volume
n= Number of moles
R= Ideal gas constant = 8.314
T= Temperature

21

What units must the ideal gas equation be in?

PV =nRT
P = Pa
V = m^3
n = moles
R = Has no units, is a constant
T = Kelvin (Celcius + 273)

22

How many Pascals = 1 atm

100,000

23

1 dm^3 = How many m^3?

0.001