Moles

Question 1

To how many significant figures should your final answer be?

Answer 1

The same as the piece of data with the most significant figures

Question 2

What do we call the number of moles?

Answer 2

The amount

Question 3

Definition for amount of substance?

Answer 3

The quantity whose unit is the mole, used as a way of counting particles

Question 4

Definition of a mole?

Answer 4

Amount of any substance, containing as many elementary particles as there are carbon atoms in 12g of Carbon 12. It contains 6.023 x10^23 atoms

Question 5

Definition of Avagadro constant?

Answer 5

Number of elementary particles per mole of a substance= (6.02x10^23)

Question 6

How to work out then amount of particles in a substance when given the moles?

Answer 6

Moles x 6.02x10^23= number of particles

Question 7

How to work out the amount of moles present if given the amount of particles?

Answer 7

Amount of particles / 6.02x10^23

Question 8

Formula linking moles, mass and molar mass?

Answer 8

Moles= mass/ molar mass

Question 9

How do you find molar mass?

Answer 9

It’s the weight of the element

Question 10

Definition of the empirical formula?

Answer 10

a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.

Question 11

How to work out the empirical formula of a compound

Answer 11

Divide the mass or percentage of each element in the compound by it’s molar mass.

Then divide these values by the smallest value there, to find the empirical formula

Question 12

Definition of molecular formula?

Answer 12

a chemical formula that gives the total number of atoms of each element in each molecule of a substance

Question 13

How to work out the molecular formula of a compound?

Answer 13

Add up the molar mass of all the elements in the compound, then divide the molar mass of the compound by this number. With this answer multiply the empirical formula to find the molecular formula

Question 14

Definition of anhydrous?

Answer 14

Crystalline compound containing no water

Question 15

Definition of hydrated?

Answer 15

Crystalline compound containing water

Question 16

Definition of water of crystallisation?

Answer 16

water molecules forming an essential part of the crystal structure of some compounds.

Question 17

How to find out how the ratio of anhydrous solid to water is in water of crystallisation?

Answer 17

Work out the moles of anhydrous solid

Work out moles of water

Look at ratio to see what number should go in front of water

Question 18

Formula for percentage error?

Answer 18

Percentage error =Total uncertainty/ value measured then x100 for a percentage

Question 19

How do you find out total uncertainty?

Answer 19

Add up all the possible errors in reading, eg. measuring scales only go to 2 d.p so there is a 0.005g error. So you can go each way so there is a 0.01g uncertainty.

Question 20

What’s a procedural error?

Answer 20

When in the method things can occur which can change your final result, but it’s difficult to measure by how much

Question 21

Method to finding reacting masses?

Answer 21

Write out balanced equation
Find the moles in which you are able to with the information given
Look at ratio and find moles of element/compound asked for
Use equations to answer question

Question 22

Definition of a solute?

Answer 22

the minor component in a solution, dissolved in the solvent.

Question 23

Definition of a solvent?

Answer 23

the liquid in which a solute is dissolved to form a solution

Question 24

Definition of a solution?

Answer 24

a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

Question 25

Formula for concentration?

Answer 25

Concentration Moles/ dm^3= moles/ volume (dm^3)

Question 26

How to convert cm^3 into dm^3?

Answer 26

Divide by 1000

Question 27

In titrations what’s a concordant result?

Answer 27

Within 0.1 cm^3 pf another result

Question 28

How to work out a concentration of an unknown acid using a titration?

Answer 28

Write equation
Work out moles of alkali
Look at ratio to find moles of acid
Use formula to work out concentration of acid

Question 29

Formula for volume occupied by 1 mole of gas, at r.t.p?

Answer 29

Formula for volume occupied by 1 mole of gas (24dm^3)= mass of one mole/ density g dm^3

Question 30

What’s the molar gas volume at r.t.p?

Answer 30

24 dm^3

Question 31

Formula for volume of gas at r.t.p?

Answer 31

Volume of gas (dm^3)= moles x 24dm^3

Question 32

How to calculate gas volumes using equations?

Answer 32

Write equation

Find moles of a known substance with information given

Use ratio to find moles of the gas your trying to find

Use equation to work out volume

Question 33

What’s the ideal gas equation?

Answer 33

Pressure x Volume= number of moles x Ideal gas constant x temperature

Question 34

In the ideal gas equation, what’s pressure measured in?

Answer 34

Pascals= Pa

Question 35

In the ideal gas equation what’s volume measured in?

Answer 35

m^3

Question 36

In the ideal gas equation what’s temperature measured in?

Answer 36

Kelvin

Question 37

In the ideal gas equation what is “the amount measured in?

Answer 37

Moles

Question 38

What’s the value of the ideal gas constant

Answer 38

8.314

Question 39

How to solve ideal gas questions

Answer 39

Convert the values into their required form

Treat the equation like in maths to solve the unknown

Question 40

How to convert degrees into kelvin?

Answer 40

Add 273

Question 41

How to convert atmostpheres to pascals?

Answer 41

Multiply by 100,000

Question 42

How to convert dm^3 to m^3?

Answer 42

Divide by 1000

Question 43

How to convert cm^3 to m^3?

Answer 43

Divide by 1000 to get dm^3, then divide by 1000 again to get m^3