1. Introductory Chemistry:
Chapter 1
Chemistry and You

2. Lab Safety Symbols Identify the following symbols
A. B. C.
D. E. F.
G. H. I.

3. What is the definition of chemistry?
Study of all substances and the changes they undergo.

4. Learning Chemistry Different people learn chemistry differently.
What do you see in the picture?
Some people see a vase on a dark background, some people see two faces.
Chapter 1

5. Problem Solving Connect the 9 dots using only four straight lines.
Experiment until you find a solution.
However, we have used 5 straight lines.
No matter which dot we start with, we still need 5 lines.
Chapter 1

6. Problem Solving Are we confining the problem?
We need to go beyond the 9 dots to answer the problem.
Chapter 1

7. Chemistry: The Central Science
Why????
Most other sciences demand an understanding of basic chemical principles, and Chemistry is often referred to as the Central Science
Chapter 1

8. Modern Chemistry
Chemistry is a science that studies the composition of matter and its properties.
Chemistry is divided into several branches:
Organic chemistry is the study of substances containing carbon
Inorganic chemistry is the study of all other substances that don’t contain carbon
Biochemistry is the study of substances derived from plants and animals
Analytical is the study of matter and ways to study the properties of matter.
Physical is the physics of chemistry. Thermodynamics and quantum mechanics.
Chapter 1 8

9. The Standard Units
Scientists have agreed on a set of international standard units for comparing all our measurements called the SI units
Quantity
Unit
Symbol
length
meter m
mass
kilogram kg
time
second s
temperature
kelvin K

10. Length SI unit = meter Commonly use centimeters (cm) About a yard
1 m = 100 cm
1 cm = 0.01 m = 10 mm
1 inch = 2.54 cm

11. Mass Measure of the amount of matter present in an object
weight measures the gravitational pull on an object, which depends on its mass
SI unit = kilogram (kg)
about 2 lbs. 3 oz.
Commonly measure mass in grams (g) or milligrams (mg)

12. Time
measure of the duration of an event
SI units = second (s)

13. Temperature Scales Fahrenheit Scale, °F Celsius Scale, °C
used in the U.S.
Celsius Scale, °C
used in all other countries
Kelvin Scale, K
The SI unit for temperature

14. Prefix Multipliers in the SI System
Symbol
Decimal
Equivalent
Power of 10
mega- M
1,000,000
Base x 106
kilo- k
1,000
Base x 103
deci- d
0.1
Base x 10-1
centi- c
0.01
Base x 10-2
milli- m
0.001
Base x 10-3
micro-
Base x 10-6
nano- n
Base x 10-9
pico p
Base x 10-12

15. What Is a Measurement? quantitative observation
every measurement has a number and a unit
every digit written is certain, except the last one which is estimated

17. Estimation in Weighing
What is the uncertainty in this reading?

18. Uncertainty in Measured Numbers
uncertainty comes from:
limitations of the instruments used for comparison,
the experimental design,
the experimenter,
nature’s random behavior

19. Precision and Accuracy
accuracy is an indication of how close a measurement comes to the actual value of the quantity
precision is an indication of how reproducible a measurement is

20. Accuracy vs. Precision

21. Precision imprecision in measurements is caused by random errors
errors that result from random fluctuations
we determine the precision of a set of measurements by evaluating how far they are from the actual value and each other
even though every measurement has some random error, with enough measurements these errors should average out – Do multiple trials!

22. Accuracy inaccuracy in measurement caused by systematic errors
errors caused by limitations in the instruments or techniques or experimental design
we determine the accuracy of a measurement by evaluating how far it is from the actual value
systematic errors do not average out with repeated measurements because they consistently cause the measurement to be either too high or too low

23. Volume Derived unit Measure of the amount of space occupied
any length unit cubed
Measure of the amount of space occupied
SI unit = cubic meter (m3)
Commonly measure solid volume in cubic centimeters (cm3)
1 m3 = 106 cm3
1 cm3 = 10-6 m3 = m3
Commonly measure liquid or gas volume in milliliters (mL)
1 L is slightly larger than 1 quart
1 L = 1 dm3 = 1000 mL = 103 mL
1 mL = L = 10-3 L
1 mL = 1 cm3

24. Mass & Volume mass and volume are extensive properties
the value depends on the quantity of matter
extensive properties cannot be used to identify what type of matter something is
if you are given a large glass containing 100 g of a clear, colorless liquid and a small glass containing 25 g of a clear, colorless liquid - are both liquids the same stuff?

25. Mass vs. Volume of Brass

26. Significant Figures
the non-place-holding digits in a reported measurement are called significant figures
significant figures tell us the range of values to expect for repeated measurements
12.3 cm
has 3 sig. figs.
and its range is
12.2 to 12.4 cm
12.30 cm
has 4 sig. figs.
and its range is
12.29 to cm

27. Counting Significant Figures
All non-zero digits are significant
1.5 has 2 sig. figs.
Interior zeros are significant
1.05 has 3 sig. figs.
Leading zeros are NOT significant – Pacific Ocean side
has 4 sig. figs.
1.050 x 10-3

28. Counting Significant Figures
Trailing zeros may or may not be significant – Atlantic Ocean Side
Trailing zeros after a decimal point are significant
1.050 has 4 sig. figs.
Zeros at the end of a number without a written decimal point are ambiguous and should be avoided by using scientific notation
if 150 has 2 sig. figs. then 1.5 x 102
but if 150 has 3 sig. figs. then 1.50 x 102

29. Determining the Number of Significant Figures in a Number
How many significant figures are in each of the following? m km
1.000 × 105 s mm
10,000 m
4 sig. figs.; the digits 4 and 5, and the trailing 0
5 sig. figs.; the digits 5 and 3, and the interior 0’s
4 sig. figs.; the digit 1, and the trailing 0’s
1 sig. figs.; the digit 2, not the leading 0’s
Ambiguous, generally assume 1 sig. fig.

30. Multiplication and Division with Significant Figures
when multiplying or dividing measurements with significant figures, the result has the same number of significant figures as the measurement with the fewest number of significant figures
× , × = = 45
3 sig. figs sig. figs sig. figs. 2 sig. figs.
÷ 6.10 = =
4 sig. figs sig. figs sig. figs.

31. Addition and Subtraction with Significant Figures
when adding or subtracting measurements with significant figures, the answer should reflect the largest uncertainty.
= = 9.21
3 sf sf sf sf
= = 0.8
2sf sf sf

32. Rounding
if the number after the place of the last significant figure is:
0 to 4, round down
drop all digits after the last sig. fig. and leave the last sig. fig. alone
add insignificant zeros to keep the value if necessary
5 to 9, round up
drop all digits after the last sig. fig. and increase the last sig. fig. by one
to avoid accumulating extra error from rounding, round only at the end, keeping track of the last sig. fig. for intermediate calculations

33. Rounding rounding to 2 significant figures 2.34 rounds to 2.3

34. Rounding rounding to 2 significant figures 0.0234 rounds to 0.023

35. Rounding rounding to 2 significant figures
234 rounds to 230 or 2.3 × 102
237 rounds to 240 or 2.4 × 102
rounds to 230 or 2.3 × 102

36. Both Multiplication/Division and Addition/Subtraction with Significant Figures
do whatever is in parentheses first,
First, evaluate the significant figures in the parentheses
Second, do the remaining steps
× ( – ) =
3 dp dp
× =
4 sf sf sf

37. Example 1.6 Perform the following calculations to the correct number of significant figures

38. Example 1.6 Perform the following calculations to the correct number of significant figures

39. Density Ratio of mass:volume
Solids = g/cm3
1 cm3 = 1 mL
Liquids = g/mL
Gases = g/L
Volume of a solid can be determined by water displacement – Archimedes Principle

40. Density Density : solids > liquids >>> gases
except ice is less dense than liquid water!
Heating an object generally causes it to expand, therefore the density changes with temperature

41. Density
Iron has a density of 7.86 g/cm3. Could a block of metal with a mass of 18.2 g and a volume of 2.56 cm3be iron?

42. Density
What volume would a g sample of air occupy if the density of air is 1.29 g/L?

43. Units Always write every number with its associated unit
Always include units in your calculations
you can do the same kind of operations on units as you can with numbers
cm × cm = cm2
cm + cm = cm
cm ÷ cm = 1
using units as a guide to problem solving is called dimensional analysis

44. Problem Solving and Conversion Factors
Conversion factors are relationships between two units
May be exact or measured
Conversion factors generated from equivalence statements
e.g., 1 inch = 2.54 cm can give or
METRIC TO ENGLISH CONVERSION ON PAGE 936 IN YOUR TEXT BOOK

45. Dimensional Analysis
Using units as a guide to problem solving is called dimensional analysis
This is the technique that we have learned to convert between two different units.

46. Problem Solving and Dimensional Analysis
Arrange conversion factors so given unit cancels
Arrange conversion factor so given unit is on the bottom of the conversion factor
May string conversion factors
So we do not need to know every relationship, as long as we can find something else the given and desired units are related to

47. Practice – Convert 154.4 lbs to kg (1 kg = 2.20 lbs)47

48. Practice – Convert 30.0 mL to quarts (1 L = 1.057 qt)

49. How many cubic centimeters are there in 2.11 yd3?

50. Practice 1.9 Convert 2.11 yd3 to cubic centimeters
Sort information
Given:
Find:
2.11 yd3
volume, cm3
Strategize
Concept Plan:
Relationships:
1 yd = 36 in
1 in = 2.54 cm
Follow the concept plan to solve the problem
Solution:
Sig. figs. and round
Round:
cm3
= 1.61 x 106 cm3
Check
Check:
Units & magnitude are correct
yd3
in3
cm3

51. Impossible Conversions
Is it possible to find how many seconds in a kilogram?
In order to do unit conversions they must be able to correspond to the same quantity.
For example, kilograms and pounds are both units of mass.

52. Graphing in Science
All graphing that is done in science must include the following:
A descriptive title
X and Y axis labeled with units.
The X – axis is the manipulated variable and the Y- axis is the responding variable.
A trend line (or line of best fit) to show the trend in the data that has been plotted.

53. Volume vs. Mass of Brass Mass, g Volume, cm3 20 40 60 80 100 120 14020 40 60 80
100
120
140
160
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
Volume, cm3
Mass, g

54. Units & magnitude are correct
Convert 30.0 mL to quarts
Sort information
Given:
Find:
154.4 lbs
Lbs to kg
Strategize
Concept Plan:
Relationships:
1 L = qt
1 L = 1000 mL
Follow the concept plan to solve the problem
Solution:
Sig. figs. and round
Round:
qt = qt
Check
Check:
Units & magnitude are correct 54

55. Scientific Investigations
Science is the methodical exploration of nature followed by a logical explanation of the observations.
Scientific investigation entails:
planning an investigation
carefully recording observations
gathering data
analyzing the results

56. The Scientific Method
The scientific method is a systematic investigation of nature and requires proposing an explanation for the results of an experiment in the form of a general principle.
The initial, tentative proposal of a scientific principle is called a hypothesis.
After further investigation, the original hypothesis may be rejected, revised, or elevated to the status of a scientific principle.
Chapter 1

57. Scientific Method a test of a hypothesis or theory
a tentative explanation of a single or small number of natural phenomena
a general explanation of natural phenomena
the careful noting and recording of natural phenomena
a generally observed natural phenomenon 57

58. Conclusions Continued
After sufficient evidence, a hypothesis becomes a scientific theory.
A natural law is a measurable relationship.
Chapter 1

59. Conclusions
Scientists use the scientific method to investigate the world around them.
Experiments lead to a hypothesis, which may lead to a scientific theory or a natural law.
Chemistry is a central science with many branches.
The impact of chemistry is felt in many aspects of our daily lives.
Chapter 1

60. QUIZE - CHAPTER -1
What is the difference between a hypothesis and theory
According to the ancient Greeks, which of the following are not basic elements found in nature:
Air
Coal
Fire
Earth
Gold
Water
Chapter 1