Practice S2.2 The covalent model with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 2
The experiment focuses on investigating the relationship between temperature and the rate of evaporation of three different volatile liquids: methanol, ethanol, and propan-1-ol.
Three identical Petri dishes are labelled A, B, and C, each containing 3.0 cm³ of a different alcohol: methanol (A), ethanol (B), propan-1-ol (C). Each dish is placed inside a temperature-controlled chamber (e.g. warm water bath or incubator) at 60 °C. A digital balance is used to measure mass loss after 5 minutes of heating.
The following data were collected:
| Alcohol | Initial mass / g | Final mass / g | Temperature / °C |
|---|---|---|---|
| Methanol | 2.38 | 0.62 | 60 |
| Ethanol | 2.40 | 1.15 | 60 |
| Propan-1-ol | 2.55 | 1.98 | 60 |
1.[2]
Calculate the average rate of evaporation of methanol in .
2.[2]
Describe the relationship between molecular size and evaporation rate based on the data.
3.[2]
Suggest why propan-1-ol evaporates more slowly than ethanol, despite being under identical conditions.
4.[2]
State the main intermolecular force present in alcohols and explain its origin.
5.[1]
Identify the functional group common to all three alcohols.
6.[1]
Draw a full structural formula of ethanol.
7.[3]
Sketch and label a Maxwell-Boltzmann distribution curve for the ethanol sample at 60 °C. Indicate the activation energy for evaporation and the fraction of particles with enough energy to overcome it.
Question 2
SL & HLPaper 1A
Which is correct for the structure shown?
I. The substance has a network covalent structure
II. The substance is a poor conductor of electricity
III. The atoms have a tetrahedral arrangement
Question 3
SL & HLPaper 1A
What type of bond is formed when two non-metals share electrons?
Question 4
SLPaper 1A
Which substance dissolves in water to form a solution that does not conduct electricity?
Question 5
HLPaper 1A
Which set correctly describes the bonding and molecular shape of the carbonate ion, ?
Question 6
SLPaper 2
Carbon is an element with several allotropes, each with distinct physical and electrical properties. Two common forms are diamond and graphite, which have very different uses in technology and industry.
1.[2]
Describe the bonding and structure of diamond in terms of its geometry and bonding type.
2.[2]
Describe the bonding and structure of graphite and how its layers are arranged.
3.[2]
Explain, in terms of electronic structure, why graphite conducts electricity whereas diamond does not.
4.[2]
State one technological use for each allotrope and relate it to a property explained above.
Question 7
SLPaper 2
Hydrogen cyanide () is a toxic gas used in chemical synthesis and historically known for its lethal effects. Understanding its bonding and polarity helps explain its reactivity and behavior in biological systems.
1.[1]
Draw the Lewis (electron dot) structure of , showing all bonds and lone pairs.
2.[1]
Predict the molecular geometry of the molecule using VSEPR theory.
3.[2]
Explain whether is a polar molecule, referring to bond polarity and molecular geometry.
4.[1]
Suggest how the polarity of influences its solubility in water.
Question 8
HLPaper 1A
What is the formal charge of the oxygen atom in ?
Question 9
HLPaper 1A
Which species has the longest carbon to oxygen bond length?
Question 10
SL & HLPaper 1A
Which of the following molecules is non-polar?