Do Now…Copy the HW & list as many elements as you can think of (without looking at a periodic table)

HOMEWORK – Write a pre-lab for

tomorrow’s separation of sand and salt lab.

ELEMENTS

Element – a substance that cannot be broken down into other substances by chemical methods.

the simplest form of matter that has a unique set of properties.

examples – gold, neon, copper, astatine, carbon, bromine…

EVERYTHING ON THE PERIODIC TABLE IS AN ELEMENT!!!

COMPOUNDS

Compound – a substance composed of a given combination of elements that can be broken down into those elements by chemical methods

ALWAYS contains DIFFERENT elements examples – magnesium oxide (MgO),

water (H2O), sodium chloride (NaCl)…

Compounds can be broken down into simpler substances by chemical methods, but elements cannot.

Ex: When sugar is heated,it goes through a chemical change.

Breaking Down Compounds

Breaking Down Compounds

Final products = carbon and water vapor

Can then break down H2O into H2 and O2 using electricity

Properties of CompoundsIn general, the properties of compounds are quite different from those of their component elements.

chlorine (Cl2)is used to kill harmful organisms in swimming pools.

sodium vapor (Na) produces the light in some street lamps.

sodium chloride (NaCl), commonly called salt, is used to season or preserve food.

Mixtures & Pure Substances

How can pure substances and mixtures be distinguished?

A pure substance ALWAYS has the same composition.

Must be an element or a compound.

Ex: water, silver

A mixture has a variable composition.

Must be a mixture of compounds and/or elements.

Ex: air, granite, chicken noodle soup

TYPES OF MIXTURES

HOMOGENEOUS the same

throughout also called a

solution Ex: salt water,

brass

HETEROGENEOUS NOT the same throughout different properties in different

parts of the same mixture Ex: sand & water, granite

REVIEW OF 3-4(Mixtures & Pure Substances)

1. Is milk a mixture or pure substance?

2. What do you think about chocolate milk?

Homogeneous mixture. It’s a mixture of water, sugar, fats and proteins that is usually the same

composition throughout.

Heterogeneous mixture. It’s a mixture of water, sugar, fats, proteins & cocoa that usually has a lot more chocolate on the bottom of the glass

than at the top… YUMMY

REVIEW OF 3-3(Elements & Compounds)

3. Passing an electric current through a certain substance produces oxygen and sulfur. This substance cannot be a(n)

a) compound.b) mixture.c) element.d) solution

REVIEW OF 3-3(Elements & Compounds)

4. Which of the following is a mixture?a) sodium chlorideb) carbon dioxidec) sucrosed) air

REVIEW OF 3-2(Chemical vs. Physical Change)

1. TRUE or FALSE:

Heating water, causing it to boil is a chemical change.

FALSE…Liquid water becomes gaseous water when it boils, but it’s still H2O!

(this is a physical change)

Chemical changes occur when different substances are produced.

REVIEW OF 3-2(Chemical vs. Physical Change)

5. A substance’s ability to change into different substances is called a:a) physical propertyb) physical changec) chemical propertyd) chemical change

REVIEW OF 3-2(Chemical vs. Physical Change)

6. Classify the following as chemical or physical changes:

a) gold melting

b) natural gas burningc) crushing an

aluminum cand) leaves turning

colors in the fall

PHYSICAL

PHYSICAL

CHEMICAL

CHEMICAL

REVIEW OF 3-1(States of Matter)

7. Which of the following states of matter takes the shape of its container and has a fixed or definite volume?a) solidb) liquidc) gasd) plasma

REVIEW OF 3-1(states of matter)

8. Rank the three most commonly cited states of matter from highest to lowest energy:a) solid, liquid, gasb) liquid, gas, solidc) solid, gas, liquidd) gas, liquid, solid