Chapter 3

Question 1

Why is it difficult to know the number of atoms or molecules that are present in a given sample of a pure substance?
* Individual atoms and molecules are too small to see–so it makes it hard to count them.
* By the time enough atoms and molecules are present for the human eye to see them in a pile there are so many of them– it makes counting them impossible.
* Atoms constantly change their chemical make-up– so you never know what you see.

Multiple answers

Answer 1

• Individual atoms and molecules are too small to see–so it makes it hard to count them.
• By the time enough atoms and molecules are present for the human eye to see them in a pile there are so many of them– it makes counting them impossible.

Question 2

Each measurements consists of three parts what are they?

Answer 2

• uncertainty
• error
• unit
• number

Question 3

True or False

The unit associated with a number does not describe the magnitude of the number.

Answer 3

False

Question 4

Which of the following units is a metric system unit?
* ounce
* pound
* liter
* gallon

Answer 4

• liter

Question 5

How many fluid ounces are there in a pint?

Answer 5

Exactly 16 fl oz

Question 6

Is the number of fluid ounces in one pint an exact or an inexact number?
* Inexact, it must be measured.
* Exact, it is defined.

Answer 6

• Exact, it is defined.

Question 7

The ____\ measurement system was defined by the work of French scientists in the 1800s

Answer 7

Metric

Question 8

Yes or No

Can the following calculation be solved?
72.6 lbs + 4.6 tons =

Answer 8

Yes

Question 9

Yes or No

Can the following calculation be solved?
12.5 gal + 5.1 L =

Answer 9

Yes

Question 10

Can the following calculation be solved?
167.5 mm² + 331.2 mm³ =

Answer 10

No

Question 11

Can the following calculation be solved?
7.63 ft x 45.2 lb =

Answer 11

Yes

the answer will have units of ft ∙lbs

Question 12

How are volume and length related?
* Volumes are defined based upon characteristic lengths of 3-dimensional objects.
* Volumes are defined based upon characteristic lengths of 2-dimensional objects.
* Volumes and lengths are interchangeable.
* Volumes and lengths are totally unrelated.

Answer 12

• Volumes are defined based upon characteristic lengths of 3-dimensional objects.

Question 13

Yes or No

Is the following conversion factor true?
12 in./ft

Answer 13

Yes

This conversion factor is universally true it comes from a definition

Question 14

Yes or No

Is the following conversion factor true?
453.6 g/lb

Answer 14

Yes

True because its from measurement and comparison using both scales