32. ANS:
A. solution (Coffee is a solution of sugar, water, and bean distillate.)
B. pure substance (Distilled water contains only one type of particle.)
C. mixture
D. pure substance (Gasoline is a pure substance in grade 9. Although it is a mixture of a
variety of hydrocarbons, students are not expected to know this yet. Should a student
suggest that it is a mixture, ask them to explain their answer upon return of the paper.)
33. ANS:
The density of a gas is lower than that of a liquid since the particles are spread out over a
greater area. For example,
34. ANS:
At the centre of the atom there are protons and neutrons.
35. ANS:
mass number = number of protons in the atom + number of neutrons in the atom
36. ANS:
Experimentation with gas discharge tubes gave evidence of small negatively charged
particles (electrons) that were common to all elements.
37. ANS:
Rutherford’s work in this case would have supported J. J. Thomson’s model of the atom.
It would have proved that there was not a localization of positive charges in one place.
38. ANS:
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