Download Chapter 2 Homework Unit Conversions/Significant digits/% Error

Chapter 2 Homework
Unit Conversions/Significant digits/% Error/Scientific Notation Homework
Convert the following: (Answers are in ()’s and are for the exponent of the answer ONLY.
1. 3.45 Km to m
(3)
10. 3.45 x 105 mm to cm (4)
2. 4.87 m to Km
(-3)
11. 5.78 x 108 cm to Km (3)
3. 1.87 m to Km (-3)
12. 6.87 x 10-2 cm to mm (-1)
4. 4.79 Km to m (3)
13. 8.90 x 10-5 mm to Km (-11)
5. 8.97 mm to cm (-1)
14. 9.00 x 10-12 mm to Km (-18)
6. 9.08 mm to dm (-2)
15. 4.56 x 10-15 cm to m (-17)
7. 8.67 cm to Km (-5)
8. 7.54 Km to pm (15)
See p. 31-35 of your textbook for extra help
9. 5.90 mm to Km (-6)
Significant Digits: (Sometimes these are called “sig figs” for short)
How many significant digits are in the following numbers? Make sure you know all of the rules for significant digits
before any test or quiz.
16. 100
24. 765.0
17. 1000
25. 0.765
18. 1000.0
26. 0.0000203
19. 101
27. 0.002000
20. 100.
28. 0.100020
21. 0.00001
29. 200 x 10-3
22. 0.001
30. 450 x 10-5
23. 100.00001
See p. 38--39 of textbook for sig fig rules and for
rules on rounding numbers.
Scientific Notation:
If a number is written in scientific notation, change it into a decimal number. If a number is written as a decimal
number, change it into scientific notation in standard form (eg. 1.23 x 103). Round any decimal numbers to the
correct number of significant digits when you put it in scientific notation. (Answers in ()’s)
31. 4.56 x 105
(456000)
40. 6780000
(6.78x106)
-5
32. 3.45x 10
(0.0000345)
41. 598201
(5.98201x105)
5
33. 44.6 x 10
(4460000)
42. 0.0000236
(2.36x10-5)
-5
34. 12.3x 10
(0.000123)
43. 0.0980
(9.80x10-2)
3
35. 136 x 10
(136000)
44. 9.76
(9.76x100)
36. 187 x 10-3
(0.187)
45. 0.00000000000003769 (3.769x10-14)
-2
37. 154323 x 10
(1543.23)
DON’T JUST DO THESE IN YOUR HEAD!
38. 25433 x 10-2
(254.33)
PUT PENCIL TO PAPER!
39. 4.56 x 100
(4.56)
See p. 31-33 of textbook for help.
Scientific notation with division and multiplication:
Multiply or divide the following problems dealing with scientific notation. All answers are to be in scientific
notation with only one significant digit. Notice that all of these must have only one sig fig in their answer because
that is the least in all of the problems! (See p. 32-33 of your textbook for help)
46. 10 x 1015/5.00 x 105
(2.0x1010)
-15
5
47. 10 x 10 /5.00 x 10
(2.0x10-20)
-15
-5
48. 10 x 10 /5.00 x 10 (2.0x10-10)
49. 40 x 10-5/20 x 1010
(2.0x10-15)
-5
-10
50. 40 x 10 /4.56 x 10
(8.8x105)
51. (5 x 105) (2 x 105)
52. (5 x 10-5) (2 x 10-5)
53. (8 x 10-5) (10 x 105)
54. (2 x 1015) (10 x 10-20)
55. (9 x 10-8) (10 x 10-10)
Know the difference between Accuracy and Precision (look on page 36)
Percent Error: (look on page 37 for help) SHOW YOUR WORK
(1x1011)
(1x10-9)
(8x101)
(2x10-4)
(9x10-17)
1. Take the average from Student A (from table 2-3 on page 37) and determine his percent error.
2. Take the average from Student B and determine her percent error.
3. Take the average from Student C and determine her percent error.
Density Homework
(See p. 27-29 of your textbook for help)
All answers are to be in decimal form (not scientific notation). All answers need to be rounded to the correct number
of significant digits.
1. A rock with a density of 4.56 g/mL and a mass of 3.45 g has what volume? (0.757 mL)
2. A rock with a mass of 4.59 g and a volume of 5.78mL has what density? (0.794 g/mL)
3. A rock with a volume of 10.0 mL and a density of 3.87 g/mL has what mass? (38.7 g)
4. A marble with a density of 8.93 g/mL and a mass of 9.00 g has what volume? (1.01 mL)
5. A rock with a volume of 80.9 mL and a density of 1.90 g/mL has what mass? (154 g)
6. A boat with a mass of 9.04 x 105 Kg and a volume of 8.90 x 107 mL has what density (notice that you will have to
convert Kg into grams before beginning this problem). (10.2 g/mL)
7. A styrofoam ball with a density of 1.05 g/L and a volume of 5.90 mL will have what mass? (notice that you will
have to convert g/L into g/mL before beginning this problem). (0.00620 g – that’s 3 sig figs)
8. A meteor with a density of 89.0 Kg/mL and a volume of 5.00 L will have what mass? (notice that Kg/mL will
have to be converted to g/mL and volume will need to be converted to mL before beginning this problem.)
(445,000,000 g or 4.45 x 108g)
9. A boat with a mass of 3.48 Kg and a density of 9.00 g/L will have what volume?
(387,000 mL or 3.87 x 105mL)
10. A watch with a mass of 0.09 Kg and a volume of 18.0 mL will have what Density? (5 g/mL)
REMEMBER:
1 L = 1 dm3
1 L = 1000 mL 1mL = 1 cm3
What’s going to be on the quiz:
1. Conversion questions (Remember how to do it if something is squared or cubed?)
2. Significant digits (you’ll get a number and be asked how many sig figs are in it)
3. Converting scientific notation to decimal form and back again.
4. Percentage Error Know the equation
5. Density problems like those found on the other side of this paper (word problems like those)
6. Problems like the conclusion questions #1-8 on Bubble Lab. You’ll be given some data and need to create a
graph and a conversion factor.