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Question 1

Define term relative isotopic mass 2m

Answer 1

Mass of the isotope compared to •1/12TH OF THE MASS OF CARBON 12

Question 2

Explain how the hydroxide ion in aqueous calcium hydroxide acts as a base when it neutralised dilute nitric acid 1 m

Answer 2

• accepts H+ ions

Question 3

Why is calcium an example of a salt? 1m

Answer 3

• H+ ions in acid is replaced by a metal ion

Question 4

Define relative atomic mass 3m

Answer 4

• the weighted mean mass of an atom

• compared with 1/12 of the

•mass of an atom of carbon- 12

Question 5

What is meant by the term electro negativity

Answer 5

• the ability of an atom to attract electrons

• in a covalent bond

Question 6

Shape of a molecule of SF6

Answer 6

Octahedral

Question 7

State one use of calcium hydroxide in agriculture and suggest why the amount of calcium hydroxide uses should not be excessive 2m

Answer 7

• used to neutralise acidic soils

• excess will cause souls to become alkaline and stops crop growth

Question 8

Describe how vander wals are formed 3m

Answer 8

• movement of uneven charged electrons

• creates a temporary dipole

• causing induced dipole in neighbouring molecules

Question 9

Is bromine toxic

Answer 9

Yes so reaxtion happen in well ventilated area

Question 10

Describe chemical test student could carry out to prove filtrate contains aqueous cl ions 2m

Answer 10

• add silver nitrate ions

• turns white and precipitates formed

Question 11

Explain what is meant by orbital 2m

Answer 11

• region within an electron that can hold two elections with opposite spins

Question 12

Define what is meant by first ionisation enegry 3m

Answer 12

• amount of energy needed to remove one electron

• from each atom in one mole

• of gasesous atoms

Question 13

How does ammonia react w water

Answer 13

NH3+ H20 —> NH4+ + OH-
Reversible reaction

Question 14

Isotope definition 1m FOR 1M

Answer 14

• atom of an element with diff number of neutrons

Question 15

How do chemsust predict shape of covalent molecules 3m

Answer 15

• electron pairs repel surrounding central atom
• shape is determined by number of bond pairs / regions AND LONE PAIRS

Question 16

Cl is more reactive than bromine explain why 4m

Answer 16

• cl will gain electron more easily than bromine

• an atom of chlorine is smaller than bromine

• outermost election is less shielded than bromine

• stronger nuclear attraction (on electron being gained) than bromine

Question 17

Explain why hcl has higher boiling point tgan F2 4m

Answer 17

• f2 has temporary dipole interactions
• hcl has permanent dipole interactions

• intermolecular forces in HCL are stronger than f2

• so more energy required to break the stronger intermolecular forces