78.1 Nm To Μm

Question: Classify each statement as an observation, a law, or a theory.
Answer: Observation:
- Neon does not react with sodium at room temperature and pressure
- Chlorine reacts violently with sodium at room temperature and pressure

Law:
- If elements are listed in order of increasing mass of their atoms, their chemical reactivity follows a repeating pattern

Theory:
- The reactivity of elements depends on the arrangement of their electrons
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Question: What is the difference between an element and a compound?
Answer: An element is a pure substance which cannot be decomposed into simpler substances. A compound is composed of two or more elements in fixed proportions.
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Question: What is the difference between a pure substance and a mixture?
Answer: A pure substance is composed of only one type of atom or molecule; a mixture is a substance composed of two or more different types of atoms or molecules.
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Question: What is the difference between a homogenous and a heterogenous mixture?
Answer: A homogenous mixture has the same composition throughout, while a heterogenous mixture has different compositions in different regions.
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Question: Classify each of the following as a pure substance or a mixture
Answer: Pure substance:
- Carbon monoxide
- Iron

Mixture:
- Clam chowder
- White wine
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Question: If it is a pure substance, classify it as an element or a compound.
Answer: Iron is an element; carbon monoxide is a compound.
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Question: If it is a mixture, classify it as homogenous or heterogenous.
Answer: White wine is homogenous; clam chowder is heterogenous.
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Question: Classify each of the following molecular diagrams as a pure substance or a mixture.
Answer: Pure substance:
- A (24 yellow spheres, 4x6)
- C (White molecules in 1 type of cluster)
- D (Red and White molecules in 1 type of cluster)

Mixture:
- B (Red and White molecules in 2 types of clusters)
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Question: Classify each substance as an element or a compound
Answer: Element:
- A

Compound:
- C
- D
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Question: Classify each of the properties of ozone (a pollutant in the lower atmosphere but part of a protective shield against UV light in the upper atmosphere) as physical or chemical.
Answer: Physical:
- bluish color
- gas at room temperature
- pungent odor

Chemical:
- very reactive
- decomposes on exposure to ultraviolet light
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Question: Classify each of the following changes as physical or chemical.
Answer: Physical:
- Sugar dissolves in water
- A platinum ring becomes dull because of continued abrasion

Chemical:
- Sugar burns when heated on a skillet
- A silver surface becomes tarnished after exposure to air for a long period of time
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Question: The following diagram represents solid carbon dioxide, also known as dry ice.

Which of the following diagrams best represents the dry ice after it has sublimed (change directly into solid to gas when heated) into a gas?
Answer: C
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Question: Perform each of the following temperature conversions.

Part A. Convert 212°F to °C (temperature of boiling water at sea level)
Part B. Convert 21°C to K (approximate room temperature)
Part C. Convert 0.00K to °F (coldest temperature possible, also known as absolute zero)
Part D. Convert 2.735K to °C (average temperature of the universe as measured from background blackbody radiation)
Answer: Part A. 100°C
Part B. 294K
Part C. -459.67°F
Part D. -270.42°C
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Question: Use prefix multipliers to express each measurement without exponents.

Part A. 44.1×10⁵ g
Part B. 11.6×10⁻¹⁰ g
Part C. 23.7×10¹¹ g
Part D. 79.8×10⁻⁷ g
Answer: Part A. 4.41 megagrams
Part B. 1.16 nanoseconds
Part C. 2.37 terameters
Part D. 7.98 microliters
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Question: Use scientific notation to express each quantity with only the base units (i.e., with no prefix multipliers)

Part A. 35 kL
Part B. 225 Gm
Part C. 133 fg
Part D. 1.5 Eg
Answer: Part A. 3.5×10⁻⁵ L
Part B. 2.25×10^11 m
Part C. 1.33×10⁻¹³ g
Part D. 1.5×10^15 g
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Question: How many 1-cm cubes would it take to construct a cube that is 2 cm on edge? (use volume formula Vol=LWH
Answer: 8 cubes
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Question: A supposedly gold nugget displaces 19.3 mL of water and has a mass of 371 g.

Part A. Calculate the density of the nugget.
Part B. Could the nugget be made of gold?
Answer: Part A. density = 19.2 g/cm³
Part B. The density of the nugget and the density of gold are ESSENTIALLY THE SAME, thus the nugget COULD BE made of gold.
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Question: Human fat as a density of 0.918 g/cm³.

How much volume (in cm³) is gained by a person who gains 10.9 lb of pure fat?
Answer: 5240 cm³

Volume gained = 10.9 lb × (453.59 g/1 lb) × (1 cm³/0.918 g) = 5390 cm³
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Question: Read each of the following to the correct number of significant figures. Note that laboratory glassware should always be read from the bottom of the meniscus. Digital balances normally display mass to the correct number of significant figures for that particular balance.

Part A. Graduated cylinder
Part B. Theormeter
Part C. Digital analytical balance
Answer: Part A. 4.50
Part B. 27.44
Part C. 0.873 g
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Question: How many significant figures are in each number?

Part A. 87,036 mi
Part B. 0.01050 m
Part C. 0.450 km
Part D. 90,201 m
Answer: Part A. 5
Part B. 4
Part C. 3
Part D. 5
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Question: Round each to three significant figures.

Part A. 79935.72
Part B. 1.557217×10⁷
Part C. 2.34850480
Part D. 0.000045609
Answer: Part A. 7.99×10⁴ (79,900)
Part B. 1.57×10⁷
Part C. 2.35
Part D. 0.0000456
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Question: Calculate the following to the correct number of significant figures.

Part A. 81.0 x 80.0 x 0.08
Part B. (4.28 × 10⁵) ÷ (8.4 × 10²)
Part C. 4.575 x 79 x 0.009
Part D. 405/2.642
Answer: Part A. 5 × 10²
Part B. 5.1 × 10²
Part C. 3
Part D. 153
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Question: Perform the following calculations to the correct number of significant figures.

Part A. 0.003 + 0.09807
Part B. 1394.5 + 8.76 + 2.72
Part C. 2.5 - 1.839
Part D. 552 + 7.0 - 50.491
Answer: Part A. 0.101
Part B. 1406.0
Part C. 0.7
Part D. 479
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Question: Perform the following calculations to the correct number of significant figures.

Part A. (23.0371 × 2.65) + 332.02
Part B. (84.9 - 24.699) ÷ 0.0049
Part C. (522 ÷ 902.9) + 5.99
Part D. [(2.03 × 10⁶) ÷ 47.100] + 159.83
Answer: Part A. 393.1
Part B. 1.2 × 10⁴
Part C. 6.57
Part D. 4.33 × 10⁴
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Question: A flask containing 8.57 mL of a liquid weighs 177.4 g with the liquid in the flask and 168.8 g when empty.

Calculate the density of the liquid in g/mL to the correct number of significant digits.
Answer: 1.0 g/mL

liquid mass = (flask with liquid mass) - (empty flask mass)
= 177.4 g - 168.8 g
= 8.6 g

density = 8.6 g ÷ 8.57 mL
= 1.0 g/mL
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Question: Perform each unit conversion.

Part A. 78.1 nm to μm (3 sigfigs)
Part B. 3549 cm³ to L (4 sigfigs)
Part C. 4956 Tm to Gm (4 sigfigs)
Answer: Part A. 7.81 × 10⁻² μm
Part B. 3.549 L
Part C. 4.956 × 10⁶ Gm
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Question: A runner wants to run 10.7 km. Her running pace is 6.5 mi/hr. How many minutes must she run? Express your answer using 2 significant figures.
Answer: 61 min

Time = 10.7km × (0.6214 mi/1 km) × (1 hr/6.5 mi) × (60 min/1 hr)
= 61 min
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Question: A certain European automobile has a gas mileage of 13 km/L.

What is the gas mileage in miles per gallon? Express your answer using 2 significant figures.
Answer: 31 miles per gallon

(13 km/1 L) × (0.6214 mi/1 km) × (0.26417 L/1 gal) = total mi/total gal= 31 mi/gal
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Question: A bedroom has a volume of 113 m³.

Part A. What is the volume in cubic kilometers (km³)?
Part B. What is its volume in decimeters cubed (dm³)?
Part C. What is its volume in centimeters cubed (cm³)?
Answer: Part A. 1.13 × 10⁻⁷ km³

V km³ = V m³ ÷ 10⁹

Part B. 1.13 × 10⁵ dm³

V dm³ = V m³ × 10³

Part C. 1.13 × 10⁸ cm³

V cm³ = V m³ × 10⁶
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Question: An infant acetaminophen suspension contains 80 mg/0.80 mL suspension. The recommended dose is 15 mg/kg body weight.

How many milliliters of this suspension should be given to an infant weighing 14 lb? (Assume 2 sigfigs.)
Answer: 1.0 mL

lb→kg→mg→mL
15 lb × (1 kg/2.205 lb) × (15 mg/1 kg) × (0.80 mL/80 mg)
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Question: The proton has a radius of approximately 1.0 × 10⁻¹³ cm and a mass of 1.7 × 10⁻²⁴ g.

Determine the density of a proton. For a sphere V = (4/3)pi r³
Answer: 4.1 × 10¹⁴ g/cm³

V = 4.2 × 10⁻³⁹ cm³ (found by doing (4/3)pi(1.0 x 10^-13)^3 in calculator
D = m/v
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Question: A hybrid electric vehicle has an EPA gas mileage rating of 58 mi/gal in the city.

How many kilometers can the car travel on the amount of gasoline that could fit in a soda can? The volume of a soda can is 355 mL.
Answer: 8.8 km

355 mL × (1 L/1000mL) × (0.26417g/1L) × (58 mi/gal) × (1 km/0.62137 mi)
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