Chapter 2: Chemistry and Measurements

Dr. Amy Hellman

What is mass?

a measure of the amount of matter in an object

What is temperature?

a quantitative measure of how hot or cold something is

State the name of the unit and type of measurement in the following:

I put 12 L of gasoline in my gas tank.

Liters, mass

State the name of the unit and type of measurement in the following:

My dog weighs 12 kg.

kilograms, mass

State the name of the unit and type of measurement in the following:

My friend is 170 cm tall.

Centimeters, length

State the name of the unit and type of measurement in the following:

It is hot today. It is 30 ℃

Celsius, temperature

State the name of the unit and type of measurement in the following:

I rode my bike 15 km today.

kilometers, distance (length)

State the name of the unit and type of measurement in the following:

I drank 250 mL of water.

milliters, mass

State the name of the unit and type of measurement in the following:

She won the race by 0.98 s.

seconds, time

How many SFs are in the following numbers? Write the number in the correct scientific notation.

0\.002 650 m

4 sig figs, 2.650x10^-3

How many SFs are in the following numbers? Write the number in the correct scientific notation.

43\.026 g

5 sig figs; 4.3x 10^1

How many SFs are in the following numbers? Write the number in the correct scientific notation.

1 044 000 L

4 sig figs, 1.044x10^6

Identify the number below as measured or exact, and give the number of significant figures in the number.

3 coins

exact; 1 sig fig

identify the number below as measured or exact, and give the number of significant figures in the number.

The diameter of a circle is 7.902 cm.

measured; 4 sig figs

identify the number below as measured or exact, and give the number of significant figures in the number.

The diameter of a human red blood cell is 0.000 006 8 m

measured, 2 sig figs

identify the number below as measured or exact, and give the number of significant figures in the number.

60 min = 1 h

exact, 1 sig fig

Write the correct value when 3.0457 g is rounded to the following:

three significant figures

3\.05g

Write the correct value when 3.0457 g is rounded to the following:

two significant figures

3\.0g

Adjust the following calculated answer to give answers with 3 significant figures.

87\.603 L

87\.6L

Adjust the following calculated answer to give answers with 3 significant figures.

0\.002 634 8 m

2\.63x10^-3m

Adjust the following calculated answer to give answers with 3 significant figures.

5\.8368 x 10^3 g

5\.84x10^3g

Adjust the following calculated answer to give answers with 3 significant figures.

5\.3 L

5\.30L

2\.012 g+ 61.09 g + 3.0 g

66\.1g

82\.409 mg + 22.0 mg

104\.4mg

106\.67 mL + 0.965 mL + 52 mL

160. mL

1\.14 g – 1.02 g / 1.02g

0\.12g

12\.67÷ 10.− 0.19

1\.1

25\.0/5.00

5\.00

65\.09 – 3.0

62\.1

56\.8 \* 0.37

21

5\.00cm \* 3.408cm / 2.0cm

8\.52cm

Fill in the blank with the correct prefix.

1000 m = 1 ___m

k(ilometer)

Fill in the blank with the correct prefix.

1× 10^−3 g = 1 ___g

m(illigram)

Fill in the blank with the correct prefix.

0\.01 m = 1 ___m

c(entimeter)

What is a cubic centimeter?

(abbreviated as cm 3 or cc) is the

volume of a 1cm x 1cm x 1 cm cube

Write equality and two conversion factors for the following pair of units:

liters and milliliters

1L/1000mL or 1000mL/1L

Write equality and two conversion factors for the following pair of units:

meters to inches

1m/39.4in or 39.4in/1m

Write equality and two conversion factors for the following pair of units:

Milligrams and micrograms

1mg/1000mcg or 1000mcg/1mg

Write equality and two conversion factors for the following pair of units:

Pounds to kilograms

1kg/2.20lbs or 2.20lbs./1kg

Equalities between different metric units of mass:

1 kg = _______ g

1000 g

Equalities between different metric units of mass:

1 g = _______ mg

1000mg

Equalities between different metric units of mass:

1 g = _______ cg

100cg

Equalities between different metric units of mass:

1 mg = _______μg

1000mcg

Identify the larger unit in the following:

mm or cm

cm

Identify the larger unit in the following:

kilogram or centigram

kilogram

Identify the larger unit in the following:

dL or μL

dL

Identify the larger unit in the following:

mcg or mg

mg

1000 m = _____

(1) 1 mm (2) 1 km (3) 1 dm

1 km

0\.01 m = _____
(1) 1 cm (2) 1 mm (3) 1 dm

1 cm

1 kg = _____
(1) 10 g (2) 100 g (3) 1000 g

1000 g

1 cL = _____
(1) 0.001 L (2) 0.01 L (3) 100 L

0\.01 L

1 L = 1000 mL; what’s the conversion factor?

1L/1000mL or 1000mL/1L conversion

1 in = 2.54 cm; what’s the conversion factor?

1in./2.54cm or 2.54 cm/1in. conversion

The car was traveling at 85 km/h.

1hr. / 85km or 85km/1hr

Medical Dosage problems:

One tablet contains 500 mg of vitamin C.

1 tablet/ 500mg or 500mg/1 tablet

What is the equation for percentages?

(part/whole) x 100

A person might have 18% body fat by mass.

18 lbs. of fat / 100 lbs. whole body weight

Keflex (Cephalexin), an antibiotic used for respiratory and ear infections, is available in 250mg capsules.

250mg/1 capsule or 1 capsule/250mg

How many milliliters are in a 1.5 tsp child’s dose of Tylenol?

8mL

If a person weighs 164 lbs, what is the body mass in kilograms?

74\.5kg

A rattlesnake is 2.44 m long. How many centimeters long is the snake?

244cm

Convert 92 mcs to seconds.

9\.2x10^-5s

How many minutes are in 1.4 days?

2\.0x10^3min

Synthroid is a synthetic hormone used to treat hypothyroidism. A doctor’s order prescribed a dosage of 0.150 mg of Synthroid. If tablets in stock contain 75 mcg of Synthroid, how many tablets are required to provide the prescribed medication?

2\.0 tablets

A cough syrup has 20.5% active ingredient. If the dose is 2 tsp of cough syrup, how many mL of the dose is active ingredient?

2510mcg drug/ kg body weight

Which occupies a greater volume:
1 kg of lead or 1 kg of aluminum?

aluminum because it’s less dense

Which has greater density?
1 gram of water or 10 grams of water?

It’s the same! b/c it’s the same material

What is the density (g/cm^3)of a 48.0-g sample of a metal if the level of water in a graduated cylinder rises from 25.0 mL to 33.0 mL after the metal is added?

6\.0g/cm^3

An unknown liquid has a density of 1.32 g/mL.
What is the volume of a 14.7-g sample of the liquid?

11\.1mL

If the idol were \~1.75 L in volume, how much would it weigh in pounds (lbs)?

74\.4lbs.

What is the density equation?

Mass/volume