Week 1 Lecture Video and Homework

Notes attached that they are part of lecture video from those 4 links and chapter 1 homework attached that they part of it in textbook.

Let me know your confused okay.

1

1

Math Review

In chemistry you will encounter very large
and very small numbers.

6

0

2

,

20

0,000,000,000,000,000,000 atoms

0.000000000

16

6 m radius of a gold atom

How do scientists simplify very
large or very small values
containing many digits?

1

2

Scientific Notation

A number written in scientific notation is
expressed as:

C x

10

n
where C is the coefficient (a number between 1-
9) and n is the exponent (a positive or negative
integer)

602,200,000,000,000,000,000,000 atoms
0.000000000166 m radius of a gold atom
2

2

3

Practice – Scientific Notation

Calculations with Exponents

1. (6 x 103)(5 x 10-5) = ________________________
2. (7 x 103)

4

= _______________________________
3. (6 x 103) + (1 x 104) = ________________________

Normal Notation Scientific Notation
Diameter of the Earth

12

8

00000 m

Length of a virus 0.00003 cm

Mass of a human 68 kg

3

4

Accuracy vs. Precision

How do scientists express the accuracy
or precision of measurement?

4

3

5

Accuracy vs. Precision

Accuracy of a measured number
is the how close it is to its
expected or true value.

Precision of measurement is the extent of
the agreement between repeated
measurements of its value.

Trial Mass (grams)
1 100.01
2 99.9

9

3 100.00

5

Accuracy – how close a measurement is to the true value
Precision – how close a set of measurements are to each other

6

4

Practice

Actual density = 19.

32

g/cm3

Trial Student 1
Density
(g/cm3)

Student 2
Density
(g/cm3)

Student 3
Density
(g/cm3)

Student 4
Density
(g/cm3)

1 19.31

18

.

24

18.75 18.60
2 19.33 19.44 18.76 19.95
3 19.31 18.99 18.74 19.40

Average 19.32 18.89 18.75 19.32

7

8

Significant Figures

How do scientists know how many digits
to record?

8

5
9

Exact vs. Measured Numbers

9

Significant Figures (SFs)

• The meaningful digits
in a measured or
calculated quantity

• All measurable digits
plus one estimated

• Sig figs in a
measurement depend
on the measuring
tool.

10

6
Practice

. l8. . . . l . . . . l9. . . . l . . . . l10. . cm
What is the length of the red line?

What is the temperature?

11

All non-zero numbers in a measured number are
significant.

Measurement Number of Significant
Figures

38

.15 cm

5.6 ft

65.6 lb

Counting Significant Figures

12

7

Leading zeros
• Precede non-zero digits in a decimal number.
• Are not significant.

Measurement Number of Significant
Figures

0.008 mm

0.0156 oz

0.0042 lb

Leading Zeros

13

Trailing zeroes

Trailing zeros
• Following non-zero numbers are significant in numbers

with decimal points.

Measurement Number of Significant
Figures

25.000 cm

20.0 kg

48600 mL

14

8

Sandwiched zeros
• Occur between nonzero numbers.
• Are significant.

Measurement Number of Significant
Figures

50.8 mm

2001 min

0.0702 lb

Sandwiched Zeros

15

Significant Figures in
Scientific Notation

In scientific notation all digits including zeros in the
coefficient are significant.

Scientific Notation Number of Significant
Figures

8 x 104 m

8.0 x 104 m

8.00 x 104 m

16

9

State the number of significant figures
in each of the following measurements:

A. 0.0

30

m
B. 4.050 L

C. 0.0008 g

Practice

17

Calculated Answers

In calculations,
§ Answers must have the

same number of significant
figures as the least precise
measured number(s).

§ Calculator answers must
often be rounded off.

§ Rounding rules are used to
obtain the correct number
of significant figures.

18

10
Practice

Adjust the following calculated answers to give
answers with three significant figures:

A. 824.75143 cm

B. 0.112486 g

19

RULE 1. In carrying out a multiplication or
division, the answer cannot have more
significant figures than either of the original
numbers.

20

11

Give an answer for the following with the correct
number of significant figures:
A. 2.19 x 4.2 =

1) 9 2) 9.2 3) 9.198

B. 4.311 ÷ 0.07 =
1) 61.59 2) 62 3) 60

Practice

21

RULE 2. In carrying out an addition or
subtraction, the answer cannot have more
digits after the decimal point than either of
the original numbers or more digits after the
leftmost uncertain digit than either of the
original numbers.

4320 cm (10th place)
– 1100 cm (100th place)

3

22

0 cm (100th place) à 3200 cm

22

12

For each calculation, round the answer to give the
correct number of significant figures.

A. 235.05 + 19.6 + 2 =

1) 257 2) 256.7 3) 256.65

B. 58000 – 1880 =

1) 56,120 2) 56,100 3) 56,000

Practice

23

24

More Practice – Sig Figs

Calculate the following:
1. 14.6608 + 12.2 + (1.500000 x 102) = ____________________

2. (5.5 x 10-8)(4 x 1010) = _______________________________
6.65 x 1045

Given number # of significant digits

26

196

28

.00
0.00

34

16
9 x 1019

1.2407661 x 10-2

24

13

25

Math Review
Units and Conversions

How do scientists show the unit
conversion process in an organized
manner ?

25
26

Equalities
• Use two different units to describe the same

measured amount.
• Examples,

1 min = 60 seconds
1 lb = 16 oz
2.20 lb = 1 kg

Equalities and Conversion
Factors

26

14

Converting a Quantity from
One Unit to Another

Dimensional Analysis: A quantity in one unit is
converted to an equivalent quantity in a different
unit by using conversion factors that express the
relationship between units.

(Starting quantity) x (Conversion factor) = Equivalent quantity

27

28

Dimensional Analysis

Old UNIT

Old UNIT

New UNIT New UNIT

=X

Conversion Ratio = the ratio of equivalent quantities

2 dozen

1 dozen

12 donuts 24 donuts

=X
28

15

The

Metric System

Why do scientists use the metric system?
Length
One meter= 1/107 the
distance from the equator
to the north pole

29

Volume and Mass

Volume Mass

30

16

Prefixes of Metric System

1 m

10 dm

Basic Units

meter (m)
gram (g)
Liter (L)

second (s)
mole (mol)
calorie (cal)

Joule (J)

deci (d) centi (c) milli (m) micro (µ) nano (n)Giga (G) Mega (M) kilo (k) hecto (h) deca (da)

1 m

1 m
100 cm

1 m
1000 mm

1 m

1 x106 µm

1 m
1 x109 nm

10 dm
1 m 1 m

1 x106 µm

10 m

1 dam

10 m
1 dam

100 m

1 hm

1 hm

1000 m

1 km

1000 m
1 km
100 m

1 x106 m

1 Mm

1 Mm
1 x106 m

1 x109 m

1 Gm

1 Gm
1 x109 m
Metric System

100 cm 1000 mm 1 x109 nm
1 m 1 m

Scale of the Universe31

Problem Solving

STEP 1: Identify the information given and the
information needed to answer.

STEP 2: Find the relationship(s) between the
known information and unknown answer, and
plan a series of steps, including conversion
factors, for getting from one to the other.

STEP 3: Solve the problem by canceling units.
STEP 4: Check the answer to make sure it makes

sense, both in magnitude and units.

32

https://scaleofuniverse.com/

17

33

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

2. The African Elephant is the largest
land mammal. Males can weigh up to
9,100 kg.
How many dekagrams is this?

Practice
33

In most other countries, the maximum speed limit
is 100 km/h. Convert this quantity to mi/h (mph).

Convert this quantity to meters/second (m/s).

34

18

35

A conversion factor
• may be obtained from information in a word problem.
• is written for that problem only.
Example 1: The price of one pound (1 lb) of red peppers is $2.

39

.

1 lb red peppers and $2.

39

$2.39 1 lb red peppers

Example 2: A tablet contains 250 mg of aspirin.

1 tablet and 250 mg aspirin
250 mg aspirin 1 tablet

Conversion Factors in a Problem

35

36

If your pace on a treadmill is 65 meters per minute,
how many minutes will it take for you to walk a
distance of 7500 feet?
(1 in = 2.54 cm)

Practice
36

19
Practice

The doctor asks for an infusion of procainamide at a
rate of 2.5mg/min. The pharmacy has mixed 3.0 g of
procainamide in 1.0 L of solution. How many mL/hr
would you set the IV pump?

37

38

A light year is the distance light travels in
one year. Sirrus Dog Star is the brightest
star in the sky, is approximately 8.6 light
years from Earth. How far (in miles) from
Earth is it if light travels 3.0 x 108 m/s?

1 km = 0.6214 mi

Practice!

38

20
39

Practice – Dimensional Analysis

1. How many inches are in 2 kilometers?
[1 in = 2.54 cm; 100 cm = 1 m; 1000 m = 1 km]

2. What is the volume of a 14 lb block of gold?
[1 lb = 453.6 g; dAu = 19.3 g/cm3]

3. Dan regularly runs a 5-minute mile. How fast is Dan
running in feet per second?
[1 min = 60 s; 1 mile = 1760 yds; 1 yd = 3 ft]

39

1. Complete the following Chapter 1 “Practice Problems” 14-23. These problems are found throughout the chapter

https://player-ui.mheducation.com/#/epub/sn_5c918#epubcfi(%2F6%2F40%5Bdata-uuid-040b8139a8f54850b4dc5e54c8ff8b5a%5D!%2F4%2F6%5Bdata-uuid-bde51c4742c941a8b33c219ff4616596%5D%2F8%5Bdata-uuid-e5f39b6ea605439cb3d9412c449f73ee%5D)

(must sign in first then go that site to do Practice Problem) For example: you see name Practice Problem 1.14 that means Chapter 1 of number 14.

2. Complete the following end of the chapter problems:

       1, 9, 11, 13, 17, 19, 21, 23, 131, 133, 141

Find this page at

https://player-ui.mheducation.com/#/epub/sn_5c918#epubcfi(%2F6%2F48%5Bdata-uuid-087463d0674a4743b1b07f17f27bd9f5%5D!%2F4%2F4%5Bdata-uuid-ac72ad9e13cd402584ed9d77bfd76f72%5D)

and must sign in first before to go that site

For example, you will see Question like 1.1 that means Chapter 1 of number 1 problem