Describe two key features of the molecular arrangement of a liquid that should be represented when drawing its molecular structure as small circles of equal size.
A student pours liquid propanone into an open beaker resting on a digital balance. Although the room temperature is below the boiling point of propanone, the mass of propanone slowly decreases as it evaporates.
State the effect of this evaporation on the temperature of the remaining propanone.
Explain, in terms of propanone molecules, why this temperature change occurs.
The specific latent heat of vaporisation of propanone is 520 J/g520\text{ J/g}520 J/g. Calculate the thermal energy required to evaporate 8.5 g8.5\text{ g}8.5 g of propanone.
Suggest two ways in which the rate of evaporation of propanone from the beaker can be reduced.
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.