Worksheet 2.2, 2.3 - More Elements Compounds and Mixtures

 

Homogeneous matter has the same composition and properties throughout a sample.  All compounds and elements are homogeneous.  Mixtures that are homogeneous are called solutions. Mixtures can also be heterogeneous when they consist of visibly different substances or phases and do not have the same composition and properties throughout a sample.

 

An alloy is a homogeneous mixture or solution containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten.

 

Classify each of the following as homogeneous or heterogeneous and then as an element, compound or mixture.  In each case, explain your classifications.  Links have been provided if you need more information.

 

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kind of matter

homogeneous or heterogeneous?

element, compound

or mixture?

explain your classification

1

black pepper

 

 

 

 

2

diamond

 

 

 

 

3

distilled water

 

 

 

 

4

air

 

 

 

 

5

bronze

 

 

 

 

6

gold

 

 

 

 

7

quartz

 

 

 

 

8

baking soda

 

 

 

 

9

nitrogen

 

 

 

 

10

Kool-aid

 

 

 

 

11

granite

 

 

 

 

12

salt

 

 

 

 

13

stainless steel

 

 

 

 

14

iron sulfide

 

 

 

 

 

15

sea water

 

 

 

 

           

Questions:

 

1.  You are given two clear liquids – one is a compound and one is a mixture.  Describe laboratory methods by which you could determine which is which.

 

 

 

 

2.  You are given two white powders, sample A and sample B.  When heated, sample A turns into a black solid and a clear liquid.  Sample B does nothing.  Is sample A an element, compound or mixture or can’t you tell conclusively?  What about sample B?  Explain.

 

 

 

 

3.  Classify each of the following properties as belonging to elements (E), compounds (C), or mixtures (M). List all possible answers.

 

a.         pure substance _____        

                                                           

b.         smallest unit retaining its properties is an atom _____

 

c.         components can be separated by physical means _____         

 

e.         components cannot be separated by physical means ____

 

f.          always the same properties throughout _____    

                       

g.         components can only be separated by nuclear changes  _____

 

h.         components can be present in varying proportions _____

           

i.          components are present in definite proportions _____              

 

k.         always homogenous _____

 

j.          components do not retain their original properties _____          

 

l.          smallest unit retaining its properties is a molecule _____

 

m.        homogeneous only if it is a solution _____           

                       

n.         contains only one kind of atom _____