Module 2 · Practice
Practice questions
Three difficulty levels. Have a proper go before checking the answers.
Section A — Easy
Recall and definitions
State the difference between an element and a compound.
Give three physical properties of a typical metal.
Which group of the periodic table contains the alkali metals?
Why are noble gases (Group 0) so unreactive?
Which separation method would you use for each:
Define solute, solvent and solution.
Section B — Medium
Short application
Predict what would happen if a small piece of potassium were dropped into water. Compare it to sodium.
Chlorine water is added to potassium bromide solution. Describe what happens and write a word equation.
A liquid melts over a range of temperatures from 95°C to 105°C. Is it pure or a mixture? Explain.
In a chromatography experiment, the solvent travels 8 cm. A spot of dye travels 6 cm. Calculate its Rf value.
Why would distillation, not just evaporation, be the right method to get drinking water from sea water?
Section C — Hard
Extended thinking
Explain, using ideas about electrons, why reactivity increases down Group 1 but decreases down Group 7.
A student dissolves 25 g of salt in 100 g of water at 20°C. The maximum mass that can dissolve at 20°C is 36 g. The student then heats the mixture to 70°C. Describe what happens to the solubility and explain.
Argon is used inside light bulbs even though it costs more than air. Suggest why.
A forensic scientist runs a chromatography test on a pen mark from a forged note. The pen used by the suspect produces three spots at Rf 0.2, 0.5 and 0.8. The note's mark gives Rf 0.2, 0.5 and 0.7. What can the scientist conclude?