Solutions to p4 to p8

1.         a.         no

            b.         yes

            c.         yes

            d.         yes

            e.         no

            f.          yes

            g.         no

2.         a.         Research the topic.

            b.         You would probably waste time by not being familiar with the topic.

3.         a.         In science, hypotheses are tested experimentally.

b.         The most reliable references are journals because they reveal the data and reasoning behind the scientist's conclusions. Journals may still contain errors, but such sources are easier to expose. The work has also been scrutinized by editors who have submitted the paper to other scientists. They check to see if they could get similar results in the lab.

4.         a.         heterogeneous because the fat floats to the top. For milk to be homogenized, the fat has to be broken up into smaller globules so that they get suspended within the rest of the milk.

            b.         heterogeneous

            c.         all solutions are homogeneous

            d.         all elements are homogeneous

            e.         all elements are homogeneous

            f.          all compounds are homogeneous

            g.         all compounds are homogeneous

            h.         heterogeneous

            i.          all compounds are homogeneous

            j.          heterogeneous

5.         a.         solution

            b.         element

            c.         compound

            d.         solution

            e.         compound

            f.          compound

            g.         element

            h.         solution

            i.          solution

            j.          solution

6.         a.         chemical

            b.         chemical

            c.         physical

            d.         chemical

            e.         chemical

            f.          physical

            g.         physical

            h.         chemical

            i.          chemical

            j.          chemical

            k.         chemical

7.         a.         chemical

            b.         physical

            c.         physical

            d.         chemical

            e.         physical

            f.          physical

            g.         chemical

            h.         physical

            i.          chemical

            j.          physical

            k.         physical

            l.          chemical

            m.        chemical

            n.         physical

8.         a.         b, e, k, m

            b.         - burns with a highly unusual blue and stinking flame

                        - melts at 119 ^oC        

9.         a.         oxidizes very easily; decomposed by water or alcohol

            b.         highly corrosive; reacts with organics; burns powdered glass; even some inerts react with it

            c.         offers a protective coating; speeds up certain reactions

            d.         none

            e.         forms sulfides; bleaches dry fruit; combines with oxygen...

10.       a. zinc              Zinc is a bluish-white, shiny metal. It is a brittle at ordinary temperatures but malleable at 100 ^oC to 150 ^oC, and it melts at 419 ^oC.  It is a fair conductor of electricity

b. oxygen         Solid and liquid oxygen are pale blue, and O₂  turns into a liquid at -183 ^oC. The gas is colourless, tasteless.

11.       a.          physical

            b.         chemical

            c.          physical

12.       A.         hydrogen

            B.         oxygen

            C.         carbon dioxide

            D.         neon

13.       a.          density

            b.         sweet-smelling an gets people to giggle

14.       measure their densities: they will be different

            or measure their boiling points

15.       evaporate the liquid from each solution; dry the white powder. The flammable one will be sugar.

16.       physical = same chemical properties

17.       chemical = a colour change accompanied by an increase in mass suggests that a gas became chemically bonded to the substance