1. Elements, Compounds, & Mixtures
Chapter 4
Elements, Compounds, & Mixtures

2. 4.1 Elements
Element- A pure substance that cannot be separated into simpler substances by chemical or physical means.
Pure Substance- A substance in which there is only one type of particles

3. Properties of Elements
Each element has its own characteristic properties.
These include boiling/melting point, density, reactivity, flammability, etc.
An element may share one or two properties with another element, but it will not share all its properties with another element. There will be specific properties for each element.

4. Classifying Elements You can use properties to identify elements.
Think about how many types of dogs there are.
How do you tell one breed from another?
Categories of Elements
Metals
Nonmetals
Metalloids

5. Classifying Elements
Metal- an element that is shiny and conducts heat and electricity well
Properties
Malleable – ability to be hammered
into sheets
Ductile – ability to be drawn into
wires

6. Classifying Elements 1.some are shiny
Nonmetal – an element that conducts heat and electric poorly
Properties
1. dull
2. brittle – not malleable
Metalloid- an element that has properties of metals and nonmetals
1.some are shiny
2. some are dull
3. somewhat malleable and ductile
4. some are good conductors of heat and electricity
5. some are poor conductors of heat and electricity

7. Classifying Elements

8. Classifying Elements Appearance Conductivity Physically Example Metal
Appearance
Conductivity
Physically
Example
Metal
 Shiny
Good
malleable., ductile
Lead, Copper
Nonmetal
 Dull
Poor
Brittle
Sulfur, oxygen
Metalloid
Some Shiny/ some dull
Some good/ some poor
Somewhat malleable and ductile
Silicon, boron

9. 4.2 Compounds
Compound- a substance made up of atoms of two or more different elements joined by chemical bonds
Examples: H2O (water), NaCl (table salt)
A particle of a compound is called a molecule
Elements do not randomly combine. They join into a specific ratios according to their masses.

10. Properties of Compounds
Each compound has its own physical properties and chemical properties.
The properties of a compound are different from the properties of the elements that form it.
Sodium Chlorine  Table Salt
Explosive soft metal Yellow Piousness Gas

11. Breaking Down Compounds
Some compounds can be broken down into their elements or simpler compounds by chemical means.
Sometimes energy in the form of heat is needed to do this.

12. 4.3 Mixtures
Mixture- A combination of two or more substances that are not chemically combined.
An example would be a salad (or salsa as in the picture). The cheese, sauce, and dough are still the same items after you make the pizza.

13. Properties of Mixtures
Sometimes you cannot see all the components like in salt water This is called a homogeneous mixture. It includes salt and water.
Since mixtures are not chemically combined, you can separate the different substances by physical methods.
Components in a mixture do not need to be in a specific ratio.
Homogeneous – same throughout
Heterogeneous – not the same throughout

14. Separating Mixtures
Sometimes you can just pick ingredients out of a mixture (pizza)
Other ways to separate mixtures include:
evaporation – separates a mixture based on boiling points Ex: salt in water
magnet – anything ferromagnetic will stick to the magnet EX. Iron & Aluminum nails in box
distillation – separates a mixture based on density. Ex: crude oil – gasoline & propane
centrifuge – separates based on particle size
Ex: blood

15. Compounds vs. mixtures Mixtures Compounds
Made of elements, compounds or both
Made of elements
No change in original properties of components
Change in original properties of components
Separated by physical means
Separated by chemical means
Formed by using any ratio of components
Formed using a set ratio of components

16. Mixture vs. compound vs. element

17. Elements, Compounds, Mixtures
Elements
Compounds
Mixtures
How many parts make it up?  1
 2 or more
 2 or more elements or compounds
Pure: more than one substance?
 pure
 Not pure
Chemically or physically combined?
 N/A
 Chemically
physically
Chemical change to make them?
 Yes no
Fixed ratio?
Yes
How separated: chemically/
physically?
Chemically

18. Journal Entry
Explain what a pure substance is. Then describe the differences between the two pure substances that you learned about.
Please write a nice neat paragraph.
Your writing should be about 8 lines.

19. Solutions, Suspensions, & Colloids

20. Solutions Solution- A mixture that appears to be a single substance.
Particles are small & cannot be filtered
Solutions have the same composition throughout.
Example: Salt Water
Solute- Substance that is dissolved. (Salt)
Solvent- The substance in which the solute is dissolved. (water)

21. Solutions Continued
The term soluble means able to dissolve. Insoluble means unable to dissolve.
Solutions can be solids, liquids, or gases.
Solubility- Measure of the amount of solute dissolved in a solvent.
This is expressed as g/mL
To increase solubility:
heat
stir
crush – smaller particles

22. Colloids
Colloid A type of mixture in which the particles are dispersed throughout but are not heavy enough to settle out
Particle size is larger than that of a solution but small enough they will still pass through a filter.
Examples of colloids: milk, fog

23. Colloids
Colloids scatter light. (fog) You can actually see the beam of light in the colloid.

24. Suspensions
Suspensions- A mixture in which the particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out.
Particles are large enough to settle out.
Suspensions can be separated by passing through a filter.
Examples: Italian salad dressing, muddy water

25. Solution, suspension, colliod
Solution
Colloid
Suspension
Particle size:
S, M, L
 small
 medium
 large
Filter?
 no
 yes
Scatter light?
Settle out?
 No no
Yes
Two examples
 Salt water
Kool Aide
 Mayo
milk
 Italian dressing
Snow globe