Scientific Notation

1. Scientific Notation

2. Scientific Notation • Very large or small numbers can be written in scientific notation. • Scientific notation uses decimals and a power of 10 to represent the original number. • To write a number is scientific notation, the number must be written with a decimal point after the first digit.

3. Converting to Scientific Notation • Write out the entire number. • Count the number of places you move the decimal point so that the number is after the first digit. • If you moved the decimal to the LEFT, write 10 raised to the positive of the number of places you moved the decimal. • If you moved the decimal to the RIGHT, write 10 raised to the negative of the number of places you moved the decimal.

4. Write In Scientific Notation 1025000 0.00257 9810000 0.2365

5. Measuring Accurately

6. Precision Accuracy vs. Precision Accuracy The extent to which a measured value agrees with the accepted value Percent error between experimental or calculated numbers and accepted number Degree of exactness to which a quantity is measured. Measurements may be precise, but may not be accurate. Based on the scale of the measuring devise.

7. Recording and Reporting Measurements • When recording a measurement, always record all values given by the devise and the “guess” at the last place value. • For example, if you measure a strip of paper to be 5.6 cm, you would want to add one more digit to the end of your number based on where you think the paper ends. If it ends right on the 0.6 mark, then your value would be 5.60 cm. If it appears to go halfway between 0.6 and 0.7 your value would be 5.65 cm.

8. Liquid Measurements- Meniscus • Water is a “sticky” molecule. • Water will climb the sides of the glass. • This is called the Meniscus.

9. The Metric System

10. Space Station Issues • The International Space Station (ISS) is regularly populated with Russians, Americans, Japanese, and Europeans. • Language is a problem. • So math is not a problem, one system of units has been adopted. Measure out 5 feet. How many meters is that?

11. The Metric System • Mass (how heavy things are) is measured in grams. • Volume (how much space something takes up) is measured in liters. • Length (how far, long, wide something is) is measured in meters.

12. Examples of Mass 1 gram of pure gold is worth ~$100 A Penny weighs 2.5 grams

13. Examples of Volume A Bottle of Soda 2 Liters Gallon of Milk 3.8 Liters http://www.citysackers.com/product_info.php?products_id=370 http://www.doobybrain.com/2008/07/24/new-coca-cola-2-liter-contour-bottle/

14. Examples of Length A stride is approximately 1 meter A car is approximately 4meter

15. Importance of Prefixes Which is easier to report? .000000003 grams or 3 nanograms

16. Prefixes King Henry Died from drinking chocolate milk Kilo = 1000 Hecto = 100 Deca = 10 Free = grams, liters, meters Deci = .1 Centi = .01 Milli = .001 http://www.fanpop.com/spots/chocolate-milk/images/1297950/title/choco-milk-photo

17. OR…. King Have Diamonds but diamonds cost money Kilo = 1000 Hecto = 100 Deca = 10 Base unit= grams, liters, meters Deci = .1 Centi = .01 Milli = .001 http://www.fanpop.com/spots/chocolate-milk/images/1297950/title/choco-milk-photo

18. K H D f d c m Convert 5000 grams to kilograms 5000.g

19. Convert 5000 millimeters to meters Convert 15 deciliters to hectoliters

20. Practice Conversions • 9000 mL to DL • .006 Km to m • 54 cg to g • .408 L to dL • 905Hm to cm • 9 g to Kg

21. Importance of the Metric System Chemists work across the globe to further our understanding. We need to be able to share our information so that we can make discoveries more quickly.

22. Conversions

23. Conversions Simplify Life Conversions allow you to represent the same amount in different units. http://www.fiftybucksaweek.com/tag/eggs/

24. Consider Eggs Eggs are not sold individually. You buy eggs or 1 dozen. 1dozen = 12 eggs. http://www.reuters.com/article/idUSTRE67J34H20100820 Units

25. Setting Up A Converson… Make sure you have the same units on the top and the same units on the bottom 3 1 dozen = x dozen __________ __________ 12 eggs 36 eggs 1 dozen = x dozen _________ ____________ 12 eggs 24 eggs 2 1 dozen = x dozen _________ __________ 12 eggs 15 eggs ?

26. 1 dozen = x dozen ___________ _____________ 12 eggs 15 eggs Step One: Cross Multiply Step Two: Divide Step Three: Check Units

27. 1 dozen = x dozen _____________ ________________ 12 eggs 30 eggs Try one yourself. = = x

28. Pressure Conversions 1 atm = 760 Torr 4 atm = ??? 1 atm 4 atm 760 Torr X Torr =

29. In chemistry we don’t use dozens. We use Moles. A mole is a number of particles.

30. Number of Particles 1 Mole = 6.02 x 1023Particles 60,200,000,000,000,000,000,000,000Particles

31. Mole Conversions • One mole of an element has a specific mass. • We can convert between moles and grams. 1 mole of Carbon = 12 grams

32. 1 mole of Carbon = 12 grams How many moles is 30 grams of Carbon?

33. 1 mole of Oxygen = 32 grams How many moles is 59 grams of Oxygen?

34. Math Review

35. You have 20 beads; 6 of them are red. What is the percentage of red beads?

36. How much is 13% of 54?

37. How much is 54% of 120?

38. How much is 98% of 6?

50. 1 mole = 40 grams. How many moles is 60 grams?