Chapter 2: Chemistry and Measurements

Temperature tells us ______ or helps us determine if ______.

- how hot something is, how cold it is outside - we have a fever

Exact numbers are not ______, do not have a limited number of ______, and do not affect the number of ______ in a calculated answer.

- measured - significant figures - significant figures

1 qt = ? mL

946 mL

Temperature (metric units)

Celsius (degree C)

State the name and type of measurement indicated by an infant that is 32.5 cm long.

a centimeter is a unit of length

State the name and type of measurement indicated by the units: A patient has a temperature of 38.5 degrees C.

a degree Celsius is a unit of temperature

State the name and type of measurement indicated by the units: A physician orders 1.5 g of cefuroxime for injection.

a gram is a unit of mass

State the name and type of measurement indicated by the units: A physician orders 1 L of a sodium chloride solution to be given intravenously.

a liter is a unit of volume

Weight

a measure of the gravitational pull on an object

Mass

a measure of the quantity of material an object contains

Perform each of the following calculations, and give an answer with the correct number of decimal places: a. 5.08 g + 25.1 g b. 85.66 cm + 104.10 cm + 0.025 cm c. 24.568 mL - 14.25 mL d. 0.2654 L - 0.2585 L

a. 30.2 g b. 189.79 cm c. 10.32 mL d. 0.0069 L

Round off each of the following numbers to three significant figures: a. 35.7823 m b. 0.0026217 L c. 3.8268 x 10^3 g

a. 35.8 m b. 0.00262 L c. 3.83 x 10^3 g

Round off each of the following numbers to two significant figures: a. 35.8 m b. 0.00262 L c. 3.83 x 10^3 g

a. 36 m b. 0.0026 L c. 3.8 x 10^3

Write each of the following in scientific notation with two significant figures: a. 5000 L b. 30000 g c. 100000 m d. 0.00025 cm

a. 5.0 x 10^3 L b. 3.0 x 10^4 g c. 1.0 x 10^5 m d. 2.5 x 10^-4 cm

Write each of the following in scientific notation with two significant figures: a. 5100000 g b. 26000 s c. 40000 m d. 0.000820 kg

a. 5.1 x 10^6 g b. 2.6 x 10^4 s c. 4.0 x 10^4 m d. 8.2 x 10^-4 kg

Identify the exact number(s), if any, in each of the following pairs of numbers: a. 5 pizzas and 50.0 g of cheese b. 6 nickels and 16 g of nickel c. 3 onions and 3 lb of onions d. 5 miles and 5 cars

a. 50.0 g b. 16 g c. 3 lb d. 5 miles

Perform each of the following calculations, and give an answer with the correct number of decimal places: a. 45.48 cm + 8.057 cm b. 23.45 g + 104.1 g + 0.025 g c. 145.675 mL - 24.2 mL d. 1.08 L - 0.585 L

a. 53.54 cm b. 127.6 g c. 121.5 mL d. 0.50 L

Round off or add zeros to each of the following to three significant figures: a. 56.855 m b. 0.002282 g c. 11527 s d. 8.1 L

a. 56.9 m b. 0.00228 g c. 11500 s d. 8.10 L

Identify the measured number(s), if any, in each of the following pairs of numbers: a. 3 hamburgers and 6 oz of hamburger b. 1 table and 4 chairs c. 0.75 lb of grapes and 350 g of butter d. 60 s = 1 min

a. 6 oz b. none c. 0.75 lb, 350 g d. none (definitions are exact)

How many significant figures are in each of the following? a. 20.60 mL b. 1036.48 kg c. 4.00 m d. 20.8 degrees C e. 60800000 g f. 5.0 x 10^-3 L

a. four SFs b. six SFs c. three SFs d. three SFs e. three SFs f. two SFs

Write the abbreviation for each of the following: a. gram b. degree Celsius c. liter d. pound e. second

a. g b. *degree*C c. L d. lb e. s

Write the abbreviation for each of the following: a. kilogram b. kelvin c. quart d. meter e. centimeter

a. kg b. K c. qt d. m e. cm

1 kg = ? lb

2.20 lb

1 inch = ? cm

2.54 cm

Celsius Temperature Scale

water freezes at 0 degree Celsius and boils at 100 degrees Celsius

Kelvin (K) Temperature Scale

water freezes at 273 K and boils at 373 K - the lowest possible temperature is 0 K - it is not written with a degree sign

Fahrenheit (degree F) Temperature Scale

water freezes at 32 degrees Fahrenheit and boils at 212 degrees Fahrenheit

1 L = ? qt

1.06 qt

1 m = ? yd

1.09 yd

1 m = ? cm

100 cm

1 kg = ? g

1000 g

1 L = ? mL

1000 mL

1 day = ? h

24 h

1 m = ? inches

39.4 inches

1 lb = ? g

454 g

1 h = ? min

60 min

1 min = ? s

60 s

Temperature (SI units)

Kelvin (K)

In which of the following pairs do both numbers contain the same number of significant figures? a. 0.00575 g and 5.75 x 10^-3 g b. 405 K and 405.0 K c. 150000 s and 1.50 x 10^4 s d. 3.8 x 10^-2 L and 3.0 x 10^5 L

a and d

Round off or add zeros to each of the following to two significant figures: a. 3.2805 m b. 1.855 x 10^2 g c. 0.002341 mL d. 2 L

a. 3.3 m b. 1.9 x 10^2 g c. 0.0023 mL d. 2.0 L

Perform the following calculations with measured numbers and give the answers with the correct number of significant figures: a. 45.26 x 0.01088 b. 2.6 / 324 c. (4.0 x 8.00) / 16

a. 0.4924 b. 0.0080 c. 2.0

Perform each of the following calculations, and give an answer with the correct number of significant figures: a. 45.7 x 0.034 b. 0.00278 x 5 c. 34.56 / 1.25 d. (0.2465 x 25) / 1.78 e. (2.8 x 10^4) x (5.05 x 10^-6) f. (3.45 x 10^-2)(1.8 x 10^5) / (8 x 10^3)

a. 1.6 b. 0.01 c. 27.6 d. 3.5 e. 0.14 f. 0.8

Round off each of the following calculator answers to three significant figures: a. 1.854 kg b. 88.2038 L c. 0.004738265 cm d. 8807 m e. 1.832 x 10^5 s

a. 1.85 kg b. 88.2 L c. 0.00474 cm d. 8810 m e. 1.83 x 10^5 s

Round off each of the following answers to two significant figures: a. 1.85 kg b. 88.2 L c. 0.00474 cm d. 8810 m e. 1.83 x 10^5 s

a. 1.9 kg b. 88 L c. 0.0047 cm d. 8800 m e. 1.8 x 10^5 s

Perform the following calculations and give each answer with the correct number of decimal places: a. 104.45 mL + 0.838 mL + 46 mL b. 153.247 g - 14.82 g

a. 151 mL b. 138.43 g

Perform the following calculations with measured numbers. Write each answer with the correct number of significant figures. a. 56.8 x 0.37 b. (2.075)(0.585)/(8.42)(0.0245) c. 25.0/5.00

a. 21 b. 5.88 c. 5.00

Perform each of the following calculations, and give an answer with the correct number of significant figures: a. 400 x 185 b. 2.40 / (4 x 125) c. 0.825 x 3.6 x 5.1 d. (3.5 x 0.261) / (8.24 x 20.0) e. (5 x 10^-5)(1.05 x 10^4) / (8.24 x 10^-8) f. (4.25 x 10^2)(2.56 x 10^-3) / (2.245 x 10^-3)(56.5)

a. 7 x 10^4 b. 0.005 c. 15 d. 0.0055 e. 6 x 10^6 f. 8.58

Perform the following calculations and give each answer with the correct number of decimal places: a. 82.45 mg + 1.245 mg + 0.00056 mg b. 4.259 L - 3.8 L

a. 83.70 mg b. 0.5 L

On a typical day, medical personnel may encounter several situations involving measurement. State the name and type of measurement indicated by the units in each of the following: a. During open-heart surgery, the temperature of a patient is lowered to 29 degrees C. b. The circulation time of a red blood cell through the body is 20 s. c. A patient with a persistent cough is given 10. mL of cough syrup. d. The amount of iron in the red blood cells of the body is 2.5 g.

a. a degree Celsius is a unit of temperature b. a second is a unit of time c. a milliliter is a unit of volume d. a gram is a unit of mass

State the name of the unit and the type of measurement indicated for each of the following quantities: a. 0.8 L b. 3.6 cm c. 4 kg d. 3.5 h e. 373 K

a. a liter is a unit of volume b. a centimeter is a unit of length c. a kilogram is a unit of mass d. an hour is a unit of time e. a Kelvin is a unit of temperature

State the name of the unit and the type of measurement indicated for each of the following quantities: a. 4.8 m b. 325 g c. 1.5 mL d. 4.8 x 10^2 s e. 28 degrees C

a. a meter is a unit of length b. a gram is a unit of mass c. a milliliter is a unit of volume d. a second is a unit of time e. a degree Celsius is a unit of temperature

On a typical day, medical personnel may encounter several situations involving measurement. State the name and type of measurement indicated by the units in each of the following: a. The clotting time for a blood sample is 12 s. b. A premature baby weighs 2.0 kg. c. An antacid tablet contains 1.0 g of calcium carbonate. d. An infant has a temperature of 39.2 degrees C.

a. a second is a unit of time b. a kilogram is a unit of mass c. a gram is a unit of mass d. a degree Celsius is a unit of temperature

A zero is not significant if it is:

a. at the beginning of a decimal number - 0.0004 s (1 SF) - 0.075 cm (2 SFs) b. used as a place holder in a larger number without a decimal point - 850000 m (2 SFs) - 1250000 g (3 SFs)

Identify the numbers in each of the following statements as measured or exact: a. There are 31 students in the laboratory. b. The oldest known flower lived 1.20 x 10^8 yr ago. c. The largest gem ever found, an aquamarine, has a mass of 104 kg. d. A laboratory test shows a blood cholesterol level of 184 mg/dL.

a. exact b. measured (?) c. measured d. measured

How many significant figures are in each of the following? a. 11.005 g b. 0.00032 m c. 36000000 km d. 1.80 x 10^4 kg e. 0.8250 L f. 30.0 degrees C

a. five SFs b. two SFs c. two SFs d. three SFs e. four SFs f. three SFs

State the type of measurement in each of the following statements: a. I rode my bicycle 15 km today. b. My dog weighs 12 kg. c. It is hot today. It is 30 degrees C. d. I added 2 L of water to my fish tank.

a. length b. mass c. temperature d. volume

Identify the numbers in each of the following statements as measured or exact: a. A patient has a mass of 67.5 kg. b. A patient is given 2 tablets of medication. c. In the metric system, 1 L is equal to 1000 mL. d. The distance from Denver, Colorado, to Houston, Texas, is 1720 km.

a. measured b. exact c. exact d. measured

Identify each of the following as measured or exact and give the number of significant figures (SFs) in each measured number: a. An adult with the flu has a temperature of 103.5 degrees F. b. A blister (push-through) pack of prednisone contains 21 tablets. c. The time for a nerve impulse to travel from the feet to the brain is 0.46 s. d. A brain contains 1.20 x 10^10 neurons.

a. measured, four SFs b. exact c. measured, two SFs d. exact (?)

Identify each of the following as measured or exact and give the number of significant figures (SFs) in each measured number: a. The mass of a neonate is 1.607 kg. b. The Daily Value (DV) for iodine for an infant is 130 mcg. c. There are 4.02 x 10^6 red blood cells in a blood sample. d. In November, 23 babies were born in a hospital.

a. measured, four SFs b. measured, two SFs c. measured, three SFs d. exact

Identify each of the following numbers as measured or exact and give the number of significant figures (SFs) in each of the measured numbers: a. 0.02080 kg b. 5.06 x 10^4 h c. 4 chemistry books

a. measured; four SFs b. measured; three SFs c. exact

Identify each of the following numbers as measured or exact and give the number of significant figures (SFs) in each of the measured numbers: a. 0.170 L b. 4 knives c. 6.3 x 10^-6 s d. 1 m = 100 cm

a. measured; three SFs b. exact c. measured; two SFs d. exact

A number is a significant figure if it is:

a. not a zero - 4.5 g (2 SFs) - 122.35 m (5 SFs) b. a zero between nonzero digits - 205 degrees C (3 SFs) - 5.008 kg (4 SFs) c. a zero at the end of a decimal number - 50. L (2 SFs) - 16.00 mL (4 SFs) d. in the coefficient of a number written in scientific notation - 4.8 x 10^5 m (2 SFs) - 5.70 x 10^-3 g (3 SFs)

Indicate if the zeros are significant in each of the following measurements: a. 0.0038 m b. 5.04 cm c. 800. L d. 3.0 x 10^-3 kg e. 85000 g

a. not significant b. significant c. significant d. significant e. not significant

Indicate if the zeros are significant in each of the following measurements: a. 20.05 degrees C b. 5.00 m c. 0.00002 g d. 120000 yr e. 8.05 x 10^2 L

a. significant b. significant c. not significant d. not significant e. significant

State the type of measurement in each of the following: a. I put 12 L of gasoline in my gas tank. b. My friend is 170 cm tall. c. Earth is 385 000 km away from the moon. d. The horse won the race by 1.2 s.

a. volume b. length c. length d. time

Significant Figures (SFs)

all the digits including the estimated digit

State the name and type of measurement indicated by the units: A medication is to be given to a patient every 4 h.

an hour is a unit of time

In which of the following pairs do both numbers contain the same number of significant figures? a. 11.0 m and 11.00 m b. 0.0250 m and 0.205 m c. 0.00012 s and 12000 s d. 250.0 L and 2.5 x 10^-2 L

b and c

The ______, a smaller unit of length, is commonly used in chemistry and is about equal to the width of your little finger.

centimeter (cm)

14.780 (three and two SFs)

three SFs: 14.8 two SFs: 15

3256 (three and two SFs)

three SFs: 3260 two SFs: 3300

8.4234 (three and two SFs)

three SFs: 8.42 two SFs: 8.4

Volume (SI unit)

cubic meter (m^3)

Mass (metric units)

gram (g)

Exact Counted Numbers

items: - 8 doughnuts - 2 baseballs - 5 capsules

Mass (SI units)

kilogram (kg)

kilograms (kg) are used for...

larger masses such as body mass

Volume (metric units)

liter (L)

Length (metric units/SI units)

meter (m)

Scientists and health professionals throughout the world used the ______ of measurement.

metric system

Exact Defined Equalities

metric system: 1 L = 1000 mL 1 m = 100 cm 1 kg = 1000 g U.S. system: 1 ft = 12 in. 1 qt = 4 cups 1 lb = 16 oz

In a laboratory or hospital, chemists work with metric units of volume that are smaller and more convenient, such as the...

milliliter (mL)

Exact Numbers

number obtained by counting items or using a definition that compares two units in the same measuring system

Measured Numbers

numbers you obtain when you measure a quantity using a measuring tool, such as your height, weight, or temperature

International System of Units (SI) (Systeme International)

official system of measurement throughout the world except for the United States

Time (metric units/SI units)

second (s)

grams (g) are used for...

smaller masses

Volume (V)

the amount of space a substance occupies