1. Chapter 17
Composition of Matter

2. Objectives Objective: Define substances and mixtures.
Objective: Identify elements and compounds.
Objective: Compare and contrast solutions, colloids, and suspensions.
CLE Evaluate pure substance and mixtures.

3. The study of matter, its properties, and changes.
Chemistry
The study of matter, its properties, and changes.

4. The basic unit that makes up all matter.
Atom
The basic unit that makes up all matter.

6. A. Pure Substances
A pure substance is made of only 1 type of matter.

7. Either an element or a compound.
A. Substance
Either an element or a compound.

8. 1. Elements Matter with identical atoms (only 1 type of atom)
All the atoms in a substance are the same

9. Elements
118 total elements known (as of 2011, but this is changing? As research continues, so do the findings)

10. 2. Compounds A compound is a substance with two or more elements chemically combined in a fixed proportion

11. Compounds

12. Compounds
Different atoms (elements) are always combined in the same ratio.

13. b. Compounds can only be separated (broken apart) into different elements by chemical or electrical processes.

14. c. Common Compounds
H2O = water
NaCl = salt
C6H12O6 = sugar / glucose

16. Substance
Element
Hydrogen
Compound
Water
Salt

17. B. Mixture Two or more substances that are NOT chemically combined
Can be easily separated by
physical means

18. 1. Homogeneous
Homogeneous mixture contains two or more gaseous, liquid or solid substances blended evenly; you can not easily see the parts.

19. a. Solutions
Liquid homogeneous mixtures with particles so small they can not be seen without a microscope.

20. Solutions salt-water)
The particles remain constantly and uniformly mixed. (Kool-aid, tea,
salt-water)

21. Homogeneous Solution

22. Mixture
Homogeneous
Heterogeneous

24. Homogeneous

25. 2. Heterogeneous Mixtures
Mixture of different materials that can be easily seen and separated.
Mixtures of materials that are not evenly blended.

27. Heterogeneous

28. 3. Colloid
Heterogeneous mixture with larger particles that never settle.

29. Colloid Colloids scatter light in the Tyndall effect.
Particles in the colloid are large enough to scatter light, but those in the solution are not.

30. Tyndall effect
Colloid

31. Colloids
Examples: jello, milk, smoke, fog, whipped cream

32. 4. Suspension
A heterogeneous mixture containing a liquid in which visible particles that settle out on standing.

33. Suspensions
One material is denser than the other so a substance will float and never mix with the other.
Examples: oil and water, muddy water, vegetable soup

34. Suspension

35. Heterogeneous
Suspension
Muddy
Water
Colloid
Milk,
fog

37. Composition of Matter 1
Suspensions
The table summarizes the properties of different types of mixtures.

38. A _______ is a type of matter with a fixed composition.
Section Check 1
Question 1
A _______ is a type of matter with a fixed composition.
A. colloid
B. mixture
C. substance
D. solution

39. Section Check 1
Answer
The answer is C. A substance can be either an element or a compound.

40. Question 2 How many elements are found on Earth? A. 5 B. 10 C. 30
Section Check 1
Question 2
How many elements are found on Earth?
A. 5
B. 10
C. 30
D. 90

41. Section Check 1
Answer
The answer is D. About 90 elements are found on Earth, and more than 20 have been made in laboratories.

42. How are compounds different from mixtures?
Section Check 1
Question 3
How are compounds different from mixtures?

43. Section Check 1
Answer
The atoms in compounds are combined in fixed proportions and cannot be separated by physical means. A mixture is made of two or more substances that can be easily separated by physical means.

44. Question 4
How can a solution be distinguished from a colloid?

45. Answer
Use the Tyndall effect to observe that colloids scatter light.

46. Objectives Objective: Define substances and mixtures.
Objective: Identify elements and compounds.
Objective: Compare and contrast solutions, colloids, and suspensions.
CLE Evaluate pure substance and mixtures.