The amount of heat energy needed to change 1 mole of a substance from a solid to liquid at melting point is called what?
Latent heat of fusion
100
Why are water and oil immiscible (do no mix)?
Water is polar, whereas oil is non-polar. Water molecules will be more attracted to each other than to the oil molecules.
100
When temperature increases, what trend is generally seen in the solubility of solids?
The solubility of solids increases
200
What is the strongest type of intermolecular force that exists between water molecules?
Hydrogen bonds
200
What units are used to describe values of specific heat capacity?
J g-1 degC-1
200
Polar molecular compounds can dissolve in water by one of two ways. What are these two ways?
By ionising or by forming hydrogen bonds with water
200
Two changes can result in the crystallisation of solutes out of solution. What are these?
Evaporation (loss of solvent) or decrease in temperature
300
How does the melting and boiling point of water compare to the other group 16 hydrides?
The melting and boiling points of water are significantly higher
300
What symbol is used to represent Specific Heat Capacity?
C
300
What happens to ionic compounds when they dissolve in water?
ions dissociate and become hydrated (surrounded by water molecules)
300
Name three factors that can affect crystal size during crystallisation?
rate of cooling, rate of evaporation, nucleation, nature of the compound
400
Why is ice less dense than water?
Because of the unique geometric arrangement of water molecules resulting from hydrogen bonding
400
How much energy, in kJ, will be required to heat 600 mL of water in a kettle from 21 deg C to 100 deg C?
198 kJ
400
What are spectator ions?
ions that do not participate in a chemical reaction
400
What is a supersaturated solution? and how can one be prepared?
A solution that contains more dissolved solute than can usually dissolve at that temperature. A supersaturated solution can be prepared by cooling a saturated solution.
500
What is the maximum number of hydrogen bonds a single molecule of water can form?
4
500
What is the latent heat of vaporisation of water?
44.0 kJ mol-1
500
What precipitate (if any) is formed when solutions of silver nitrate and sodium chloride are mixed?
Silver chloride (AgCl)
500
Describe how a solubility curve can be derived.
Prepare solutions of various concentrations by adding solute to water and heating until dissolved. Gradually cool the samples while stirring and observe the temperature at which crystals first appear. Convert results to mass/100g and plot results on graph.