1. Today is Monday, February 5th, 2018
In This Lesson:
Mixtures
(Lesson 2 of 6)
Today is Monday, February 5th, 2018
Pre-Class:
You know, I really like to save money whenever I can. This year, I’m hoping to stop paying so much for salt at the grocery store. So, the next time I’m at the beach, I’m going to take some of the salt out of the salt water.
Is that possible? How?

2. Today’s Agenda Types of matter Properties of matter
Interactions of matter
Also known as mixtures
Where is this in my book?
P. 38 and following…

3. By the end of this lesson…
You should be able to classify matter based on its composition.
You should be able to determine the error of measurements taken during a laboratory process.

4. Types of Matter
As you can imagine, having a definition as broad as “has mass, takes up space” leads to an awfully large amount of matter in the world.
More than just the phases of matter, chemists have ways of classifying matter by its composition.

5. Classifying Matter MATTER Mixture Pure Substance Homogeneous Mixture
Heterogeneous
Mixture
Element
Compound

6. Substances and Mixtures
MATTER
Pure Substance
Mixture
Physical Separation
Mixtures can be separated by physical means.
You’ll do this in a lab!

7. Substances Substances have: Uniform compositions MATTER
Distinctive characteristics
Examples:
NaCl (Salt)
Al (Aluminum)
O2 (Oxygen)
MATTER
Substance
Mixture
Element
Compound

8. Elements and Compounds
Elements are substances that cannot be broken down into components.
Elements are composed of only one type of atom.
Example:
Hydrogen
Oxygen
Uranium
MATTER
Substance
Mixture
Element
Compound

9. Elements and Compounds
Compounds are composed of two or more elements.
Compounds can be broken down chemically.
Example:
Glucose (C6H12O6)
Water (H2O)
Carbon Dioxide (CO2)
MATTER
Substance
Mixture
Element
Compound
Chemical Separation

10. Mixtures Mixtures are physical blends of two or more substances.
Examples:
Salt water
Sand and water
Blood
Air
Vegetable soup
MATTER
Substance
Mixture
Homo-geneous
Hetero-geneous

11. Substances and Mixtures
Homogeneous mixtures are also called solutions.
They have a “single state” – in other words, it all looks the same.
Examples:
Salt water
Crystal Light
Apple juice
MATTER
Substance
Mixture
Homo-geneous
Hetero-geneous

12. Substances and Mixtures
Heterogeneous mixtures are not uniform.
They have more than one state – in other words, it doesn’t all look the same.
Examples:
Cookies and cream ice cream
Fruit salad
Vegetable soup
MATTER
Substance
Mixture
Homo-geneous
Hetero-geneous

13. Closure It’s time for the “Mixture or Substance” game!
[cue 70’s game show music]
I’ll show you a picture of a substance or mixture, you tell me which one it is.
Imaginary bonus points if you can identify whether it’s an element or compound, or a heterogeneous or homogeneous mixture.
That sentence had many uses of the word “or.”

14. Classification of Matter
Is it a mixture or a substance?
Substance
Mixture
Mixture
Mixture
Mixture
Salt
Salt Water
Air
Soil
Blood
Compound
Homogeneous
Homogeneous
Heterogeneous
Homogeneous

15. Classification of Matter
Is it a mixture or a substance?
Mixture
Substance
Mixture
Substance
Mixture
Sand
Water
Gasoline
Iron
Steel
Heterogeneous
Compound
Homogeneous
Element
Homogeneous
[Alloy]

16. Classification of Matter
Is it a mixture or a substance?
Substance
Mixture
Mixture
Mixture
Mixture
Aluminum
Sand & Salt
Sand & Water
Raisin Bread
Brass (copper & zinc)
Element
Heterogeneous
Heterogeneous
Heterogeneous
Homogeneous
[Alloy]

17. Classification of Matter
Is it a mixture or a substance?
Mixture
Substance
Mixture
Mixture
Substance
Wood
Carbon Dioxide
Cement
Candle Wax
Sugar
Heterogeneous
Compound
Homogeneous
Homogeneous
Compound

18. Physical and Chemical Properties
In addition to physical and chemical reactions, like we learned about previously, there are also physical and chemical properties.
They work mostly the same way.

19. Physical and Chemical Properties
Physical properties are those that can be observed without actually causing a chemical reaction.
Examples:
Density
Hardness
Melting/boiling points
Color
Smell

20. Important Physical Properties of the States of Matter

21. Important Physical Properties of the States of Matter
Solids:
Definite shape/definite volume
Not easily compressed
Liquids:
Indefinite shape/definite volume
Gases:
Indefinite shape/indefinite volume
Easily compressed

22. Physical and Chemical Properties
Chemical properties are those that cannot be observed without actually causing a chemical reaction.
Examples:
Flammability
Corrosion (or rust-ability)

23. Intensive and Extensive Properties
There are also properties considered intensive and extensive.
Intensive properties are those that apply to any amount of a substance.
Examples:
Color
Melting/boiling point
Combustibility

24. Intensive and Extensive Properties
Extensive properties are those that vary based on the amount of a substance.
Examples:
Volume
Length
Mass
Weight

25. Closure Part Deux Now let’s separate a mixture ourselves.
Separation of a Mixture Lab
There’s just one more thing you need…

26. Percent Error
Today will be our first lab with a considerable amount of calculations.
Because we will all have slightly different numbers, it’s important for us (and for chemists) to be able to measure the accuracy of the measurements we’ve taken.

27. Accuracy
When measuring anything, there is usually some error on the part of the scientist or the equipment.
The value calculated in the experiment is thus called the experimental value.
There is, of course, the “true” value; the one we would expect to get if everything went perfectly.
This is called the accepted value because scientists have agreed that it is correct.
Accepted value is sometimes called theoretical value, ideal value, or expected value.

28. Percent Error
Therefore, to find how far off we are from what we should have gotten, we need to calculate a statistic called percent error.
Here’s the formula – be careful of order of operations:

29. Percent Error Example
You calculate the mass of an object to be 57.3 grams. However, your teacher tells you the object is actually 59 grams. What is your percent error?

30. Closure
You collect 23 mL of liquid in a graduated cylinder. Unfortunately, the reaction you did was only supposed to make 21.4 mL. What is your percent error?