1. World of Chemistry Chapter 2 Matter
Unit 2 Matter
World of Chemistry
Chapter 2 Matter

2. Chapter Objectives: Identify the composition of matter
Distinguish between elements, compounds, and compounds
Define the three states of matter
Distinguish between physical and chemical properties
Distinguish between physical and chemical changes
Distinguish between mixtures and pure substances
Identify methods to separate mixtures

3. What is matter? Matter: anything that mass and occupies space (volume)
Matter is classified into two categories:
1. Pure substance: a substance that is composed of one type of element or compound; cannot be separated (aluminum foil, water)
2. Mixture: a substance that is composed of two more elements or compounds; can be separated (Ex.brass, Gatorade)

4. Pure Substance (Liquid water)
Mixture (salt water = NaCl in H2O)

5. What is matter?
Element: a substance made with only one type of atom (H, He, Li, etc.)
Atom: the smallest form of an element that retains its chemical properties; tiny particles
Molecule: a combination of two or more atoms (O2, H2, H2O, CH4)
Compound: a substance composed of two or more different atoms (CH4, AlCl3)

6. Element
Atom
24K gold is a pure substance. It is made of only gold atoms

7. Molecules and CompoundsCl Cl
chlorine, Cl2 S
penicillin,with carbon, nitrogen, sulfur, oxygen, hydrogen atoms O O
sulfur dioxide, SO2

8. Types of Mixture
Homogeneous (solution): a mixture that has a uniform appearance
Ex’s: salt water, brass (alloy), air
Alloy: a mixture of metal elements
Heterogeneous: a mixture that contains regions with different physical properties
Ex’s: dirt, vegetable soup, oil/water

9. Identifying the following mixtures as homogeneous or heterogeneous

10. Physical vs. Chemical
Physical property: characteristics that describes a substance
color, odor, texture, taste
mass, volume
density, boiling point, melting point
physical state (gas, liquid, solid)
Physical change: change in one or more physical properties without changing its chemical composition

11. Physical Examples Physical properties Physical changes
bubblegum has a pink color
carbon monoxide is odorless
the density of water is 1.0g/mL
Ms. Cipolla is 1.54m
Physical changes
cutting wood
breaking glass
melting silver
boiling water

12. Physical vs. Chemical
Chemical property: characteristics that describe how a substance will change into a new substance
flammability, radioactivity, oxidizes
reactivity with water, acids, bases, air
Chemical change: change that occurs when a substance turns into a new substance with different physical and chemical properties

13. Chemical Examples Chemical properties Chemical changes
potassium violently reacts in water
silver tarnishes in air
hydrogen gas is produced from zinc in acid
uranium-235 decay
Chemical changes
lighting a match
photosynthesis
baking bread
bleaching clothing

14. States of Matter Matter exists in one of three states (or phases):
Solid – rigid, fixed shape and volume
Liquid – fluid, no defined shaped, fixed volume
Gas – random motion, no defined shape or volume
State changes:
Use buckmisterfullerene for solid, one in a million container for liquid, and ping pong balls in container for gases

16. Separating Mixtures
Various techniques can be used to separate mixtures:
Distillation: used to separate substances in a solution based on differences in boiling point
Filtration: used to separate solid substances from a mixture
Magnetization: used to separate based on magnetic properties

17. condenser
vapor
liquid solution
separated material
Distillation – a liquid solution is heated. Components are separated out when the temperature reaches their individual boiling point. These now gases cool off as they pass through a condenser and turn back into a liquid where they are collected in a separate container.

18. Filtration – a heterogeneous mixture (usually composed of a liquid and solid) is passed through a filter, i.e. paper. Material that is small enough to pass through the filter is collected in a separate container.