Quantitative Chemistry (4) ✅

Question 1

what is relative atomic mass?
(Ar/RAM)

Answer 1

the mass of an atom compared with carbon-12 isotope

Question 2

what is the mass of the carbon-12 isotope

Answer 2

12

Question 3

the sum

what is the relative FORMULA mass

Answer 3

the sum of relative atomic masses of all the atoms present in the formula of a compound

Question 4

how do you find the % of an element in a compound
(RFM=relative formula mass)

Answer 4

mass of element in a compound
—————————————— x100
Mr/RFM of compound

Question 5

the RAM of sub in g

what is the mole of a substance?

Answer 5

the relative atomic mass of a substance in grams

Question 6

how many particles does one mole of any substance contain?

Answer 6

Question 7

write out the triangle used for the formula that shows the relationship between the mass (in g), the Ar/RAM or Mr/RFM, and moles

(triangle between Mass, moles and Ar/Mr)

Answer 7

Question 8

which number is the Ar/Mr

Answer 8

12

Question 9

how many g in one kg

Answer 9

1000g

Question 10

how many kg in one tonne

Answer 10

1000kg

Question 11

how many g in one tonne

Answer 11

1000,000g

Question 12

how do you work out % yield

Answer 12

actual yield
—————- x100
theoretical yield

Question 13

maximum mass that can be obtained in a

what is the theoretical yield

Answer 13

the maximum mass of product that can be obtained in a chemical reaction

Question 14

what is the actual yield

Answer 14

the mass of product actually produced in the lab at the end of the reaction

Question 15

what is percentage yield

Answer 15

measures the proportion of products formed in a reaction and tells us how efficient a chemical process is

Question 16

how do you work out the theoretical yield

Answer 16

use the moles calculation-
moles = mass
———
Ar/Mr

Question 17

Name 3 reasons the percentage yield of the product is less than 100%

Answer 17

-loss by mechanical transfer from one container to another
-loss of product in separation from the reaction mixture
-reaction is reversible and may not go to completion

Question 18

what is empirical formula?

Answer 18

formula which shows the simplest whole number ratio of atoms of each element in a compound

Question 19

what is molecular formula

Answer 19

formula which shows the actual number of atoms of each element in a molecule

Question 20

EF and RMM of compound

what two things are essential to know when working out the molecular formula

Answer 20

empirical formula of compound
relative molecular mass of compound

Question 21

what is the method for heating copper (II) sulfate crystals

Answer 21

• weigh a test tube containing copper (II) sulfate crystals
• set up apparatus in the picture
• find boiling point of collected liquid
• add water

Question 22

when heating copper sulfate crystals why do we surround one test tube with water

Answer 22

to cool/condense the vapour formed

Question 23

when heating copper sulfate crystals why is one test tube tilted downwards

Answer 23

so liquid doesn’t run back down to the solid

Question 24

what happens to the mass when heating copper sulfate crystals

Answer 24

the mass decreases

Question 31

What is water of crystallisation?

Answer 31

Water contained in hydrated crystals.

Question 32

What do blue copper (II) sulfate crystals contain?

Answer 32

Water of crystallisation.

Question 33

What is the term for blue copper (II) sulfate crystals that contain water?

Answer 33

Hydrated.

Question 34

What is formed when blue copper (II) sulfate crystals are heated?

Answer 34

Anhydrous copper (II) sulfate.

Question 35

True or False: Anhydrous copper (II) sulfate contains water of crystallisation.

Answer 35

False.

Question 36

Fill in the blank: The solid formed when blue copper (II) sulfate crystals are heated is called _______.

Answer 36

Anhydrous copper (II) sulfate.

Question 37

what does anhydrous mean

Answer 37

doesn't contain water of crystallisation

Question 38

how could you ensure the heating of copper sulfate crystals reaction was complete

Answer 38

heat, cool + weigh test tube A, then repeat until mass of test tube A remains constant

Question 39

what is the word equation for heating copper sulfate crystals

Answer 39

hydrated copper sulfate --> anhydrous copper sulfate + water blue solid --> white solid + colourless liquid

Question 40

example of thermal decomposition

Answer 40

As copper (II) sulfate crystals form the solution they take in water which is known as water of crystallisation and it can be removed by heating.

Question 41

what is thermal decomposition

Answer 41

the breakdown of a substance using heat

Question 42

What is the process of thermal decomposition?

Answer 42

Thermal decomposition is the process in which a chemical compound breaks down into simpler substances when heated.

Question 43

What must be done to ensure thermal decomposition is complete?

Answer 43

Heating until constant mass must be carried out to ensure thermal decomposition is complete.

Question 44

Fill in the blank: Any thermal decomposition can be carried out to completion by heating until _______.

Answer 44

constant mass

Question 45

what does the . mean in the empirical formula of hydrated salts (CuSo4 . 5H20)

Answer 45

indicates salt contains water of crystallisation

Question 46

what does hydrated mean

Answer 46

solid crystals contain water of crystallisation

Question 47

what does anhydrous mean

Answer 47

substance doesn't contain water of crystallisation that is water

Question 48

what does water of crystallisation mean

Answer 48

chemically bonded into the crystal structure

Question 49

what does dehydration mean

Answer 49

removal of water crystallisation

Question 50

what is the method of finding the mass of water present in a hydrated salt

Answer 50

weigh the crucible add hydrated compound and reweigh crucible and hydrated salt heat cool and weigh repeat until no further change in mass

Question 51

diagram of finding the mass of water present in a hydrated salt

Answer 51

Question 52

label

Answer 52

Question 53

why is it necessary to heat hydrated salts until the mass is constant

Answer 53

to ensure all the water of crystallisation has been removed