Practice S1.1 Introduction to the particulate nature of matter 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.
A student investigates the melting behaviour of three substances: X, Y, and Z. The data collected are shown below.
Table 1. Mass of substance and temperature change during heating
| Substance | Mass (g) | Time to melt (s) | Initial temp (°C) | Final temp (°C) | Melting point Observed (°C) |
|---|---|---|---|---|---|
| X | 5.00 | 60 | 22 | 140 | 134 |
| Y | 5.00 | 25 | 21 | 130 | 106–120 |
| Z | 5.00 | 45 | 23 | 135 | 118 |
State one piece of evidence from the data that suggests substance Y is a mixture.
Determine the average rate of temperature increase for substance Z in °C per second.
Using the data, discuss the melting behaviour of substance X and substance Y.
The substances are cooled and observed again. Only substance X reforms a solid with the same sharp melting point on reheating.
Suggest what this indicates about the type of matter in substance X.
Suggest one improvement to this experiment that would help determine whether a substance is pure more accurately.
The diagram below shows a simple apparatus used to investigate the properties of sodium chloride and carbon tetrachloride in both solid and molten states.
State the type of bonding present in sodium chloride and in carbon tetrachloride.
Explain why sodium chloride does not conduct electricity in the solid state but does when molten.
Suggest why carbon tetrachloride does not conduct electricity in any state.
Use the diagram and your knowledge of structure and bonding to deduce which substance(s) contain delocalized ions.
State and explain the difference in melting point between sodium chloride and carbon tetrachloride.
Predict the state of carbon tetrachloride at room temperature. Justify your answer based on its intermolecular forces.
Draw the Lewis (electron dot) structure for the ion and a molecule
A student investigates the solubility of potassium nitrate (KNO₃) in water at different temperatures. The results are shown in the table below.
Table 1. Solubility of potassium nitrate in water
| Temperature (°C) | Mass of KNO₃ dissolved in 100 g water (g) |
|---|---|
| 10 | 21 |
| 20 | 31 |
| 30 | 45 |
| 40 | 63 |
| 50 | 85 |
| 60 | 109 |
Outline the trend shown in the data.
Calculate the average rate of increase in solubility between 20 °C and 50 °C in g °C⁻¹.
Use the data to predict the solubility of potassium nitrate at 70 °C.
A student stirs 40 g of KNO₃ into 100 g of water at 20 °C. Predict what will be observed after the solution is allowed to stand, and explain your answer.
Suggest one reason why solubility increases with temperature for most ionic compounds.
Draw a sketch graph of solubility (y-axis) vs. temperature (x-axis) using the data provided.
State the definition of a pure substance in terms of the particulate model.
Describe two observable differences between a physical change and a chemical change.
A student heats a sample of naphthalene (mothballs). Initially, the solid is white and crystalline. Upon heating, it directly converts into a gas, skipping the liquid phase.
State the name of this change of state.
Suggest why this is considered a physical change rather than a chemical change.
A sample of matter contains water and ethanol, which are completely miscible. The student is asked to obtain pure ethanol from the mixture.
Identify the method used to separate this mixture.
Explain how this method works using the idea of differences in physical properties.
State the assumptions of the kinetic molecular theory as it applies to gases.
Explain why the temperature of a substance remains constant during a change of state, even though heat is still being added.
State one difference between a compound and a mixture.
Outline how filtration and distillation can be used to separate components of a mixture of sand, salt and water.
A student is given an unknown substance. The student performs tests and observes the following:
Deduce whether the substance is most likely an element, compound or mixture, giving a reason for your answer.
Explain why evaporation and crystallization are not suitable methods to separate the components of a homogeneous mixture of ethanol and water.
What is the sum of the coefficients when the equation for the combustion of ammonia is balanced using the smallest possible whole numbers?
What change of state occurs when a gas becomes a solid without passing through the liquid phase?
Which diagram best represents particles in a gas?
Which statement correctly describes a compound?