chemistry questions for a course that i am doing.

a) A colourless liquid is left to evaporate in an open container; when the liquid has fully evaporated, you observe a white crystalline residue in the container.

b) A colourless liquid is left to cool in a cold bath. At 0 °C, white crystals start to form in the liquid. At a constant temperature of 0 °C, a continuous formation of crystals can be observed until all the matter has solidified.

c) A liquid with a density of 0.90 g/ml is left to evaporate in an open container. When half or the liquid has evaporated, the remaining liquid has a density of 0.95 g/ml.

d) A liquid is left to evaporate in an open container; eventually, the liquid will evaporate completely, leaving no residue.

e) A brown liquid is swirled in a centrifuge. A pale brown substance is observed at the bottom of the tube and a dark brown transparent liquid is observed at the top of the tube.

1) 16 marks: Determine to which category each of the following substances belongs. Is it a mixture, a solution, a compound or an element? Justify each answer. Remember that there can be more than one correct answer, depending on your own interpretation of the situation. (2 marks each)

a) Motor oil-

b) Sugar crystals

c) Solvent or turpentine

d) Antifreeze

e) Snowflake

f) Solder

g) Lasagne

h) Silver

2) 8 marks: Give two examples of each of the following, other than any previously mentioned in the lesson: (2 marks each)

a) Mixture

b) Solution

c) compound

d) element

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