1. Matter – Properties and Changes
Chapter 2
Matter – Properties and Changes

2. 2.1 Properties of Matter
Pure substance (substance) – matter that has a uniform and definite composition.
Physical property – quality of a substance that can be observed without changing the substances composition

3. 2.1 Properties of Matter Two Types of Physical Properties
Extensive properties – dependent upon the amount of substance present.
Mass, volume, and length
Intensive properties – independent of the amount of substance present.
density

4. 2.1 Properties of Matter
Chemical property – of a substance to combine with or change into one or more other substances.

5. Physical Properties Chemical Properties Melting point Decomposition
Boiling
Color
Density
Magnetism
Crystalline
shape
Malleability
Ductility
Luster
Refractive
index
Decomposition
Chemical reactivity
Water
Acid
Precipitation rxn
Combustion rxn
Odor
Taste
Hardness
solubility

6. 2.1 States of Matter Solids
Particles close together -strong forces hold particles together
Particles vibrate – held too strongly to break apart
Constant shape and volume
Almost incompressible

7. 2.1 States of Matter Liquids
Particles farther apart - particles are moving fast enough to partially break away
Particles stay together – not moving fast enough to escape
Constant volume but not shape
Almost incompressible

8. 2.1 States of Matter
Gases
Particles far apart – no attractive forces
Particles moving very fast
No constant shape or volume
Easily compressed
Vapor – matter as a gas that is usually a liquid or solid at room temperature

9. 2.1 Uncommon 4th State Plasma High energy and temperature
Charged gaseous particles

10. 2.2 Changes in Matter
Physical change – change that results in a dramatically different appearance yet leave the composition of the substance unchanged.
Crumpling of a sheet of aluminum foil.
Changes in state

11. 2.2 Changes in Matter
Chemical change – of a process where one or more other substances change into new substances.
How do you know if it’s a chemical change has occurred?
Color change
Solid or liquid precipitate
Odor or gas produced.
Light or energy involved.

12. mass reactants = mass products
2.2 Changes in Matter
Conservation of Mass
Law of conservation of mass – in an ordinary chemical or physical reaction, mass can’t be created or destroyed.
mass reactants = mass products

13. 2.2 Changes in Matter

14. 2.2 Changes in Matter
A reaction between sodium hydroxide and hydrogen chloride gas produces sodium chloride and water. A reaction of g of sodium hydroxide with g of hydrogen chloride gives off g of water. What mass of sodium chloride is formed in the reaction?
22.85 g
20.82 g
10.29 g
sodium hydroxide + hydrogen chloride  sodium chloride + water
22.85 g g = sodium chloride g
43.67 g = sodium chloride g
33.38 g sodium chloride

15. 2.3 Mixtures of Matter Classifying Mixtures
Mixture – physical blend of two or more pure substances.
Heterogeneous mixture – nonuniform composition.
Homogeneous mixture (solution) – uniform composition.
Phase – part of a system with uniform composition.

16. 2.3 Mixtures of Matter Separating Mixtures
Filtration – separate by passing through a barrier

17. 2.3 Mixtures of Matter Separating Mixtures
Distillation – uses differences in boiling points to separate liquid-solid or liquid-liquid mixtures.

19. 2.3 Mixtures of Matter Separating Mixtures
Crystallization – formation of pure solid particles from a solution.
Chromatography – separate components of a mixture based on the speed they move across another material.

20. 2.4 Elements and Compounds
Element – pure substance that can’t be separated into simpler substances
Can’t be separated by chemical or physical means.
91 naturally occurring
When naming
First letter capitalized
Others are lowercase

21. 2.4 Elements and Compounds
Periodic Table of Elements
Row is called a “period”
Column is called a “group” or “family”
Elements in the same group have similar chemical and physical properties
Why is it called a periodic table?
There is a “periodic” repetition of the pattern in similar properties as you move from period to period

22. A column is called a group or family!
A row is called a period!

23. 2.4 Elements and Compounds
Compound – 2 or more elements combined chemically
Can be separated chemically, but not physically
About 10 million known compounds
100,000 new each year
H2O, NaCl, and C12H22O11
Symbols represent elements
Subscripts represent the proportion of the elements in the compound

24. Classifying Matter Matter Can it be separated physically? No Yes
Pure Substance
(Definite Composition)
Can it be separated
chemically?
Mixture
(Variable composition)
Is it uniform? No
Yes
Yes No
Element
Examples: carbon, gold,
iron, and more
Compound
Example: water and
sodium chloride
Homogeneous mixture
Examples: air and
tap water
Heterogeneous mixture
Examples: soup and
river water

25. 2.4 Elements and Compounds
Law of Definite Proportion – in a chemical compound, the masses of the elements are always in the same proportion.
18 g of H2O
100 g H2O
H = 2 g
O = 16 g
H = g
O = g
Ratio of O = 16 or 8 H
Ratio of O = or 8 H

26. 2.4 Elements and Compounds
Percent by mass – the ratio of the mass of each element to the total mass of the compound

27. 2.4 Elements and Compounds
A g sample of aspirin is made up of 6.03 g of hydrogen, g of carbon, and g of oxygen. What is the percent by mass of hydrogen in aspirin?
= %
= %

28. 2.4 Elements and Compounds
If you have g of aspirin, how much hydrogen do you have?
Remember %Aspirin = 4.48%
What is 4.48% of g?
945.5 g  = g
42.4 g

29. 2.4 Elements and Compounds
Law of Multiple Proportions – if 2 elements form more than 1 compound, the different masses of 1 element that combine with the same mass of the other element are in ratios of small whole numbers.
17 g of H2O2
9 g of H2O
H = 1 g O = 16 g
H = 1 g O = 8 g
O ratio is 16:8
or 2:1

30. How do you show this law if the second element isn’t the same mass?
Law of Multiple Proportions – if 2 elements form more than 1 compound, the different masses of 1 element that combine with the same mass of the other element are in ratios of small whole numbers.
What ratio of X combines with a fixed ratio of Y for these two compounds?
X = 1.2 g
Y = 1.11 g
X = 2.6 g
Y = 4.8 g =
1.08 gX =
.54 gX
1 gY
1 gY
1.08 g to .54 g
2 to 1