Atoms and reactions module 2.1

Question 1

define relative atomic mass

Answer 1

the weighted mean mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12.

Question 2

why do different isotopes of the same element react in the same way?

Answer 2

because chemical reactions involve electrons which isotopes have the same number. neutrons make no difference to chemical reactivity

Question 3

what is the formula to find the relative atomic mass ?

Answer 3

Ar=(relative isotopic mass x percentage abundance) + relative isotopic mass x percentage abundance) / 100

Question 4

What is the gas equation at room temperature and pressure

Answer 4

n= volume/24

Question 5

Define empirical formula

Answer 5

The simplest whole number ratio of atoms of each element in the compound

Question 6

Anhydrous

Answer 6

Substance that contains no water molecules

Question 7

Define hydrated compounds ?

Answer 7

The crystalline compound containing water molecules

Question 8

Water of crystallisation definition

Answer 8

Water molecules that form n essential part of the crystalline structure of a compound

Question 9

What are two types of crystals ?

Answer 9

Hydrated and anhydrous

Question 10

What is the main difference between strong acids and weak acids ?

Answer 10

Strong acids are fully disossiciates whereas weak acids are partially dissociates

Question 11

What do we make when we react a acid with a metal carbonate ?

Answer 11

Salt,carbon dioxide and water

Question 12

alkalis

Answer 12

• give out OH- ions when dissolved in water

Question 13

What do we make when a alkali reacts with a acid ?

Answer 13

• salt and water

Question 14

What is a oxidising agent ?

Answer 14

Chemical they accepts electrons

Question 15

What is a reducing agent ?

Answer 15

Chemicals that donate electrons

Question 16

isotopes

Answer 16

atoms of the same element with different numbers of neutrons and therefore different masses

Question 17

relative isotopic mass

Answer 17

the mass compare with 1/2th mass of carbon-12

Question 18

relative isotopic mass

Answer 18

the mass compare with 1/2th mass of carbon-12

Question 19

why do some transition meal ions have f=roman numerals?

Answer 19

• they form more than one ion with different charges so the oxidation number is shown by the roman numerals.

Question 20

formulae of nitrate

Answer 20

NO3-

Question 21

formulae of carbonate

Answer 21

C03 2-

Question 22

formulae of sulphate

Answer 22

SO4 2-

Question 23

formulae of hydroxide

Answer 23

OH-

Question 24

formulae of ammonia

Answer 24

NH4+

Question 25

formulae of a zinc ion

Answer 25

Zn2+

Question 26

Acid + carbonate

Answer 26

Salt,carbon dioxide and water

Question 27

Acid + metal oxide

Answer 27

Salt + water

Question 28

Acid + alkali

Answer 28

Salt + water

Question 29

Acid + metal

Answer 29

Salt + hydrogen

Question 30

Reason for not a 100% perventage yield

Answer 30

- reaction may be at equilibrium and may not go to completion - side reactions may lead to by- prouducts - some of reactant or product may be left behind in the apparatus - prouct loss

Question 31

Salts

Answer 31

Any chemical compound formed from an acid when a H+ ion from the acid had been replaced by a metal ion or another positive ion e.g ammonium ion

Question 32

Acid salts

Answer 32

- one H+ ion is replaced not all. | - still behaves as an acid as the remaining H+ ion can be replaced

Question 33

Base

Answer 33

- H+ acceptors,neutalise acods

Question 34

Oxidation number of oxygen in peroxides

Answer 34

-1

Question 35

Oxidation number of hydrogen in metal hyrdroxides

Answer 35

-1

Question 36

Kpa to Pa

Answer 36

x 1000

Question 37

Dm3 to m3

Answer 37

/ 1000

Question 38

Cm3 to m3

Answer 38

/ 1000000

Question 39

How to work out percentage yield

Answer 39

- find the amount of mole in the limiting reagent ( if not given find moles in all reactants smallest mole number is limiting) - use the equation (mole ratio) to find the amount of moles expected in the product ( theoretical yield) - divide actual/ theoretical x100

Question 40

What does a high atom econmy mean

Answer 40

- less waste/ bu- products made

Question 41

Sulfuric acid

Answer 41

- H2SO4

Question 42

Nitric acid

Answer 42

- NH03

Question 43

Ethanoic acid

Answer 43

CH3COOH

Question 44

Dative covalent bonding

Answer 44

One atom supplies both the shared electrons in a covalent bond

Question 45

Ionic lattice

Answer 45

Repeating pattern | Oppositely charge ions