Chemistry Exam 1 Study Guide
21. what does numerical uncertainty mean in measurement
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34. When a piece of magnesium (density = 1.738 g/mL) is placed in a container of liquid water (density = 1.0 g/mL), the piece of magnesium will sink as the weight of the metal is denser than the liquid.
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3. When 5.820 × 10^-3 is correctly converted to its standard form the number becomes
.005820
7. When 0.043489 is correctly rounded to two significant figures the number becomes
0.043
18. On an autumn day in Chicago the outdoor temperature was 40 °C. What was this outdoor temperature in °F
104°F
23. A beaker contains 145.7 mL of a saline solution. If 24.2 mL of the saline solution are removed from the beaker, what volume of solution remains
121.5 mL
13. Which length is the longest
15,000 cm
54. A small banana contains 203 mg of the nutrient potassium. You would need to eat approximately _____ small bananas in one day to obtain the recommended daily intake of 3.5 g of potassium.
18
16. If a piece of rock has a volume of 0.53 L and a mass of 1224 g, what is the density of the rock in g/mL
2.3 g/mL
11. Carry out the following calculation and report the answer using the proper number of significant figures: 12.6ft/.45s
28ft/s
17. A hiker with hypothermia has a body temperature of 82 °F. What is his body temperature in °C
28°C
22. Air has a density of 0.001226 g/mL. What volume of air would have a mass of 1.0 lb
3.7 x 10^2 L
19. The recommended dietary allowance for calcium for teenage children is 1,300 mg per day. If a typical 8.0-fl oz glass of reduced-fat milk contains 298 mg of calcium, how many fluid ounces of milk does a teenager need to drink to get the entire recommended amount of calcium from this milk
35 oz
10. Carry out the following calculation and report the answer using the proper number of significant figures:18.141 × 24.1
4.40 x 10^2
12. Which is the proper conversion factor for converting a mass expressed in pounds (lb) to the same mass expressed in grams (g)
454g/1 lb
47. which is larger 0.0007270 or 5.7 × 10^-3
5.7 x 10^-3 (False if it asks if decimal is larger than scientific notation)
20. The estimated average daily requirement of folic acid for pregnant females is 520 micrograms. how is this written
520 μg
9. Carry out the following calculation and report the answer using the proper number of significant figures: 26.251 + 33.2
59.5
15. If a package of nuts weighs 21.3 oz, what is the mass of the package expressed in milligrams
6.03 x 10^5
1. The number 0.00657980 expressed correctly using scientific notation is
6.57980 x 10^-3
14. What is the mass in kilograms of an individual who weighs 144 lb
65.5 kg
8. When 7.6390 × 108 is correctly rounded to three significant figures the number becomes
7.64 x 10^8
2. The measurement 8,235,544mm expressed correctly using scientific notation is
8.235544 x 10^6
5. What are physical changes
A physical change alters the material without changing its composition. ie) melting and boiling
4. What is a pure substance
A pure substance is composed of only a single component (atom or molecule). It has a constant composition, regardless of sample size or origin of sample. It cannot be broken down to other pure substances by a physical change. ie) table sugar and water
6. What is an exact number
An exact number results from counting objects or is part of a definition. ie) 10 fingers, 10 toes, 1 meter = 100 centimeters
28. The base unit for mass in the metric system is the meter.
False
35. In reading a number with a decimal point from left to right, all digits starting with the first nonzero number are significant figures.
False
40. The measurement 10.3 cm has more significant figures than the measurement 10.3 m.
False
41. The density of olive oil is less at 200 °C than at 25 °C as it is liquid.
False
24. PVC plastic, which is used in pipes, is an example of a synthetic material.
True
25. Nitrogen gas (N2) would properly be classified as a element.
True
26. Changes in state such as melting and boiling are physical changes.
True
27. A compound can be broken down into simpler substances.
True
29. The base unit for volume in the metric system is liter (L).
True
30. An inexact number results from a measurement or observation and contains some uncertainty.
True
31. 1 dL is larger than 1 mL.
True
32. Specific gravity is a quantity that compares the density of a substance with the density of water.
True
33. When the liquid carbon tetrachloride (density = 1.59 g/mL) is added to water, the top layer will be the water layer.
True
36. Dissolving sugar in water involves no chemical changes.
True
37. Assuming the numbers are measured values, when multiplying 762.85 by 15 the answer should be reported with two significant figures.
True
38. If the density of a substance is greater than 1 g/mL, the mass of a sample of this substance will be greater than the volume of the sample.
True
39. Dividing a number by 10^5 is the same as multiplying a number by 10^-5.
True
42. One Kelvin is the same size as one degree Celsius.
True
43. The temperature 1°C is higher than 1°F.
True
44. The temperature 1 °C is higher than 1 K.
True
45. Elements and compounds are both classified as pure substances.
True
46. The number 87,927,000 is larger than the number 9.7 × 106.
True
48. A mixture can be separated into its components by physical changes.
True
49. For a number written in scientific notation, a negative exponent indicates the value of the number is less than 1.
True
50. A _____ change converts one material to another.
chemical
51. To use conversion factors to solve a problem, set up the problem with any unwanted unit in the numerator of one term and the _____ of another term, so that unwanted units cancel.
denominator
55. When crude oil leaks into the ocean from an oil tanker, the crude oil floats because it is _____ dense than water.
less
52. If you have equal masses of two different substances (A and B), and the density of A is twice the density of B, then the volume of A is _____ the volume of B.
one-half or ½
53. Every measurement is composed of a number and a _____.
unit
