Chapter 3.1 CYU Answers
1. (a) concrete = mechanical mixture
(b) shampoo = solution
(c) air = solution
(d) tap water = solution
(e) cookie dough = mechanical mixture
Note: Some cookies (e.g., ginger snaps or shortbread) might be identified as solutions
because only one type of particle is visible.
2. Two tests that will identify a substance as a mechanical mixture are:
• Will a filter remove part of the mixture? If yes, then it is a mechanical mixture.
• Can more than one kind of particle be identified? If yes, then it is a mechanical mixture.
3. See Figure 3.2. Remind students that there is usually more solvent than solute.
Figure 3.2
Substance
Solute
Solvent
(a) salt water
salt
water
(b) baking soda and
water
baking soda
water
(c) air (78% nitrogen,
22% oxygen and other
gases)
oxygen and
other gases
nitroge
n
(d) gold jewellery (90%
gold, 10% silver)
silver
gold