Our Last Lesson Together (10-6)

Titrations

100

Q1: What is the purpose of a titration?
A) To prepare a rough solution of an acid
B) To prepare a pure, soluble salt. 
C) To measure mass changes in a reaction
D) To separate mixtures

B) To prepare a pure, soluble salt.

200

Q2: Why is phenolphthalein preferred over universal indicator in titrations?
A) It is cheap and easy to buy
B) It changes colour gradually
C) It shows a sharp colour change at neutralisation
D) It reacts with metals

C) It shows a sharp colour change at neutralisation

300

Which piece of apparatus measures the solution added in a titration?
A) Conical flask
B) Pipette
C) Burette
D) Beaker

C) Burette

400

You get titres of 24.1, 24.0, 24.4, 23.9. Which are concordant?
A) 24.1, 24.0, 23.9
B) 24.1, 24.4
C) 24.4, 23.9
D) All four

A) 24.1, 24.0, 23.9

Ionic Bonding + Polyatomic ions

100

Sodium chloride is held together by:
A) Covalent bonds
B) Metallic bonds
C) Ionic bonds
D) Hydrogen bonds

C) Ionic bonds

200

What is the charge on the sulfate ion?
A) 1−
B) 2−
C) 2+
D) 1+

B) 2−

300

Q3: Which of these is a polyatomic ion?
A) Na⁺
B) Cl⁻
C) OH⁻
D) Mg²⁺

C) OH⁻

400

Q4: Which statement about ionic compounds is false?
A) They conduct electricity as solids
B) They have high melting points
C) They are made of ions arranged in a lattice
D) They are usually soluble in water

A) They conduct electricity as solids

Covalent Bonding

100

Q1: How are atoms held together in covalent bonds?
A) Shared pairs of electrons
B) Transferred electrons
C) Attraction between ions
D) Delocalised electrons

A) Shared pairs of electrons

200

Q2: Which molecule has a simple molecular structure?
A) NaCl
B) H₂O
C) Diamond
D) Graphite

B) H₂O

300

Q3: Which property is typical of simple covalent molecules?
A) High melting and boiling points
B) Low melting and boiling points
C) Conduct electricity as solids
D) Conduct electricity in solution

B) Low melting and boiling points

400

Q4: Which molecule contains a double covalent bond?
A) H₂
B) O₂
C) CH₄
D) Na₂O

B) O₂

Allotropes of Carbon

100

Q1: Which of these are allotropes of carbon?
A) Sodium
B) Diamond
C) Graphene
D) Fullerenes

B) Diamond
C) Graphene

200

Q2: Diamond is hard because:
A) It has weak intermolecular forces
B) Each carbon is bonded to four others in a giant lattice
C) Layers can slide over each other
D) It is made of molecule

B) Each carbon is bonded to four others in a giant lattice

300

Q3: Graphite can conduct electricity because:
A) Delocalised electrons move through layers
B) Carbon atoms are free
C) The layers are strong
D) It contains ions

A) Delocalised electrons move through layers

400

Graphene is:
A) A single layer of graphite
B) Soft like diamond
C) Non-conductive
D) Made of molecules

A) A single layer of graphite

Fuels and Atmosphere

100

Q1: Complete combustion of a hydrocarbon produces:
A) CO₂ and H₂O
B) CO and O₂
C) CO₂ only
D) C and H₂O

A) CO₂ and H₂O

200

Q2: Which gas is a major greenhouse gas?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Helium

C) Carbon dioxide

300

Incomplete combustion produces:
A) CO and soot
B) CO₂ and water
C) Only water
D) Only carbon

A) CO and soot

400

Q4: Which is a renewable fuel?
A) Coal
B) Natural gas
C) Petrol
D) Bioethanol

D) Bioethanol

Empirical Formulae

100

Empirical formula shows:
A) Actual number of atoms
B) Ratio of atoms
C) Molecular mass
D) Number of molecules

B) Ratio of atoms

200

A compound contains 40% carbon, 6.7% hydrogen, 53.3% oxygen. Empirical formula? (Remember, C = 12, H = 1, O = 16 )
A) CHO
B) C₂H₂O
C) CH₂O
D) C₂H₄O₂

A) CHO

300

A compound contains 32 g of sulfur and 16 g of oxygen. Determine the empirical formula of the compound.
(Ar: S = 32, O = 16)

Empirical formula = SO

400

A compound contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. Determine the empirical formula. 

(A_r: C = 12, H = 1, O = 16)

Empirical formula = CH₂O

Mass Calculations

100

Q1: Relative formula mass of Na₂SO₄? (use your periodic table or the one on the wall!)
A) 142
B) 120
C) 96
D) 100

A) 142

200

Q2: How many moles in 36 g of H₂O? (A_r : H=1, O=16)
A) 1
B) 2
C) 0.5
D) 3

B) 2

300

Q3: Mass = moles × M_r. What is the mass of 2 moles of CO₂? Hint - M_r is the relative formula mass
A) 44 g
B) 88 g
C) 22 g
D) 66 g

B) 88 g

400

Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen: 

Mg + 2HCl -> MgCl₂ + H₂

If 24 g of magnesium reacts completely with excess hydrochloric acid, calculate the mass of magnesium chloride produced.

95 g

Acids and Alkalis

100

Strong acids:
A) Fully ionise in water
B) Partially ionise
C) Always have pH 7
D) Neutralise bases slowly

A) Fully ionise in water

200

Universal indicator turns green at:
A) pH 1
B) pH 7
C) pH 14
D) pH 0

B) pH 7

300

Q3: Which is an alkali?
A) HCl
B) NaOH
C) H₂SO₄
D) CO₂

B) NaOH

400

Q4: What is formed when an acid reacts with a metal?
A) Salt + water
B) Salt + hydrogen
C) Salt + oxygen
D) Water only

B) Salt + hydrogen