HSSC chemistry

The atomic number of carbon is:

• 1 12
• 2 14
• 3 6
• 4 8

The number of moles in 36 g of water (molar mass 18 g/mol) is:

• 1 0.5
• 2 18
• 3 2
• 4 4

The pH of a neutral solution at 25°C is:

• 1 7
• 2 0
• 3 1
• 4 14

Avogadro's number is approximately:

• 1 3.0 × 10⁸
• 2 6.02 × 10²³
• 3 6.02 × 10²⁰
• 4 1.6 × 10⁻¹⁹

The number of valence electrons in a sodium atom (1s² 2s² 2p⁶ 3s¹) is:

• 1 11
• 2 8
• 3 1
• 4 2

The general formula of the alkanes is:

• 1 CₙH₂ₙ₊₂
• 2 CₙH₂ₙ₋₂
• 3 CₙH₂ₙ
• 4 CₙHₙ

The bond in sodium chloride is:

• 1 Covalent
• 2 Ionic
• 3 Hydrogen bond
• 4 Metallic

The oxidation number of manganese in KMnO₄ is:

• 1 +2
• 2 +4
• 3 +7
• 4 −1

Boyle's law states that at constant temperature the pressure of a gas is:

• 1 Inversely proportional to its volume
• 2 Proportional to its volume
• 3 Proportional to the square of its volume
• 4 Independent of its volume

A catalyst changes a reaction by:

• 1 Increasing the yield only
• 2 Becoming a product
• 3 Increasing its rate without being used up
• 4 Lowering the temperature

The hybridisation of carbon in methane is:

• 1 sp³
• 2 sp
• 3 sp³d
• 4 sp²

The shape of the ammonia molecule is:

• 1 Trigonal pyramidal
• 2 Linear
• 3 Planar triangle
• 4 Tetrahedral

In the reaction N₂ + 3H₂ ⇌ 2NH₃, raising the pressure shifts the equilibrium toward:

• 1 No change
• 2 Ammonia
• 3 Nitrogen
• 4 Hydrogen

The pH of a 0.01 M solution of hydrochloric acid is:

• 1 12
• 2 1
• 3 2
• 4 0.01

Oxidation is the:

• 1 Gain of neutrons
• 2 Loss of electrons
• 3 Gain of electrons
• 4 Loss of protons

In the electrolysis of brine, chlorine gas is formed at the:

• 1 Container wall
• 2 Salt bridge
• 3 Anode
• 4 Cathode

The functional group of an alcohol is:

• 1 −NH₂
• 2 −COOH
• 3 −OH
• 4 −CHO

The IUPAC name of CH₃CH₂OH is:

• 1 Methanol
• 2 Ethanol
• 3 Propanol
• 4 Ethanal

The molarity of a solution made by dissolving 4 g of NaOH (molar mass 40 g/mol) in 500 mL of solution is:

• 1 0.1 M
• 2 0.2 M
• 3 0.8 M
• 4 2 M

The number of structural isomers of butane (C₄H₁₀) is:

• 1 4
• 2 1
• 3 3
• 4 2

The most electronegative element is:

• 1 Chlorine
• 2 Fluorine
• 3 Oxygen
• 4 Nitrogen

Across a period of the periodic table from left to right, the atomic radius generally:

• 1 Stays the same
• 2 Increases
• 3 Doubles
• 4 Decreases

The number of sigma bonds in an ethene molecule (C₂H₄) is:

• 1 4
• 2 6
• 3 2
• 4 5

Water has a higher boiling point than hydrogen sulfide because of:

• 1 Metallic bonding
• 2 A larger mass
• 3 Hydrogen bonding
• 4 Ionic bonding

Avogadro's law says that equal volumes of gases at the same temperature and pressure contain:

• 1 The same density
• 2 The same mass
• 3 The same number of atoms of each element
• 4 The same number of molecules

For an exothermic reaction the enthalpy change ΔH is:

• 1 Positive
• 2 Negative
• 3 Zero
• 4 Infinite

The effect of a catalyst on the value of the equilibrium constant is that it:

• 1 Doubles it
• 2 Increases it
• 3 Decreases it
• 4 Does not change it

The mass of 0.5 mol of calcium carbonate (molar mass 100 g/mol) is:

• 1 100 g
• 2 50 g
• 3 200 g
• 4 5 g

An ionic compound conducts electricity when it is:

• 1 Solid
• 2 Cold
• 3 Molten
• 4 A powder

The molecular formula of benzene is:

• 1 C₆H₁₂
• 2 C₆H₁₄
• 3 C₅H₆
• 4 C₆H₆

The reaction of methane with chlorine in ultraviolet light is a:

• 1 Elimination reaction
• 2 Condensation reaction
• 3 Substitution reaction
• 4 Addition reaction

Which of these is a weak acid?

• 1 Acetic acid
• 2 Hydrochloric acid
• 3 Sulfuric acid
• 4 Nitric acid

The percentage of oxygen by mass in water (H = 1, O = 16) is about:

• 1 88.9%
• 2 11.1%
• 3 50%
• 4 16%

In an electrochemical cell, reduction takes place at the:

• 1 Cathode
• 2 Wire
• 3 Anode
• 4 Salt bridge