1. Opening Assignment page 112-113
1. Find the element that has an atomic number of 14. What is it?
2. What is its chemical symbol?
3. This element combines with 2 oxygen atoms to make sand. What is the chemical formula for sand? Take a guess if you do not know.

2. Compounds What makes a pure substance a compound and not an element or a mixture?

3. Pure Substance Compounds
What is a compound?
'A Compound made of 2 or more different elements chemically combined

4. Look at these pictures……Which is a compound? Which is an element?
O CH4

5. Compounds What are the characteristics of compounds
The have a definite chemical composition…
You can write a chemical formula..
H2O
K2CO3

6. Compounds Can separate by chemical means
Other characteristics
A compound cannot be separated into different substances by mechanical means
Can separate by chemical means

8. Great Combinations Looking at molecules of common compounds

9. Question 3 Carbon Dioxide
How many atoms are there? _________
How many elements are there?_________
What is the chemical formula? ___________

10. Number 7 Sand - Silicon Dioxide
How many atoms?
How many elements in this molecule?
What is the chemical formula?

11. Number 8 chalk – Calcium carbonate
How many atoms?
How many elements are there in this element?
Chemical formula?

12. Homework Number 6
Ba(OH)2
Ba - _______
O - _______
H - ________