1. Welcome to the World of Chemistry

2. The Language of Chemistry
The elements, their names, and symbols are given on the PERIODIC TABLE
How many elements are there?
116 elements

3. Recommended works Memorize: - SI Base Units (Table 1.2, p.17).
Recommended works
 Memorize:
- SI Base Units (Table 1.2, p.17).
- Common decimal prefixes used with SI units (Table 1.3, p.17).
- Name and Symbol of elements in the Periodic Table (cover pages)
- Elements that occur as molecules (Figure 2.15, p.58)
- Some common monatomic ions of the elements (Figure 2.17, p.60).
- Common polyatomic ions (Table 2.5, p.62)
- Numerical prefixes for hydrates and binary covalent compounds (Table 2.6, p.63)
Practice problems in textbook (Answers in Appendix E)

4. Keys to the Study of Chemistry
Chapter 1
Keys to the Study of Chemistry

5. 1.1 Some Fundamental Definitions
Chemistry and Its Central Themes
Chemistry: the study of matter and transformations it undergoes, as well as the energy involved in such changes.
-The Central Themes of Chemistry
Study the observable changes in matter to understand their unobservable causes.
Understand & Explain --- > Predict & Control
By investigating the molecular reasons for the processes occurring in our macroscopic world.

6. What is matter? Matter is anything that
- has mass (sometimes expressed
as weight)
- and occupies a space
Forms of ENERGY are NOT matter.
example: heat or light does not occupy space and has no mass.

7. Physical & Chemical Properties
of Matter
Physical Properties: Density, color, melting point, hardness, phase, texture, … are physical properties of matter. Observing a physical property can be done without altering the makeup of a substance.
Chemical Properties: Chemical composition (what matter is made of), and chemical reactivity (how matter behaves). Observing a chemical property alters the substance.

8. Physical vs. Chemical changes
Physical changes are simply change of states with no composition changes of matter.
Chemical changes occur when new materials are formed by a change in the way atoms are bonded together
- Reactivity changes with the formation of new substances.
- Heat, light, or electrical energy is often emitted or absorbed.

9. Learning Check Classify each of the following as a
1) physical change or 2) chemical change.
A. ____Burning a candle.
B. ____Ice melting on the street.
C. ____Toasting a marshmallow.
D. ____Cutting a pizza.

10. States of Matter Gas (e.g., the air you breathe)
A physical state is a form that matter can take.
Gas (e.g., the air you breathe)
- has no definite shape or volume
is expandable and highly compressible
Particles are far apart and move very fast
Liquid (e.g., the water you drink)
- has no definite shape but a
definite volume
is practically incompressible
Particles are close together but mobile; they move slowly
Solid (e.g., the food you eat)
-has a definite shape and volume
-is essentially incompressible
- Particles are close together in a fixed arrangement; they move very slowly

11. 1.3 The Scientific Approach: Developing a model
Observations include gathering information and collecting data.
Hypothesis is a tentative explanation to account for a set of observations and to be tested.
Laws describe how nature works
Theories explain why observations, hypotheses, or laws apply under many different observations.

12. Scientific Inquiry in Practice
Observation: The sound from a CD in a CD player skips.
Hypothesis 1: The CD player is faulty.
Experiment 1: When I replace the CD with another one, the sound from this second CD is OK.
Hypothesis 2: The original CD has a defect.
Experiment 2: When I play the original CD in another player, the sound still skips.
Theory: My experimental results indicate the
original CD has a defect.

13. 1.4 Chemical Problem Solving
Physical properties such as height, volume, and temperature that can be measured are called physical quantities. Both a number and a unit of defined size is required to describe physical quantity.

14. Units and Conversion Factors in Calculations
A conversion factor
Is a fraction obtained from an equality.
Equality: 1 inch = 2.54 cm
Can be written as a ratio with a numerator and denominator that express the same quantity in different units
Can be inverted to give two ratios of the same quantity
1 in and cm
2.54 cm in.

15. Learning Check Write conversion factors for each pair of units:
A. liters and mL
B. hours and minutes
C. meters and kilometers

16. Converting between unit systems
When solving a problem, the idea is to set up an equation so that all unwanted units cancel, leaving only the desired units.

17. A Systematic approach to Solving Chemistry Problems
Write the initial and final units.
Write a unit plan to convert the initial unit to the final unit.
Write equalities and conversion factors.
Use conversion factors to cancel the initial unit and provide the final unit.
Be sure to check unit cancellation.

18. An Approach to Problem Solving
What is 165 lb in kg?
STEP 1 Initial 165 lb Final: kg
STEP 2 Plan lb kg
STEP 3 Equalities/Factors
1 kg = 2.20 lb
2.20 lb and kg
1 kg lb
STEP 4 Set Up Problem to use conversion factors to cancel the initial unit and provide the final unit.
165 lb x kg = kg
2.20 lb

19. Using Two or More Factors
Often, two or more conversion factors are required to obtain the unit needed for the answer.
Unit > Unit > Unit 3
Additional conversion factors are placed in the setup to cancel each preceding unit
Initial unit x factor 1 x factor 2 = Final unit
Unit x Unit x Unit = Unit 3
Unit Unit 2

20. Problem Solving How many minutes are in 1.4 days?
Initial unit: 1.4 days Final unit: min.
Factor Factor 2
Plan: days > hr > min
Set up problem:
1.4 days x 24 hr x 60 min = 2.0 x 103 min
1 day hr
2 SF Exact Exact = 2 SF

21. Check the Unit Cancellation
Be sure to check your unit cancellation in the setup.
The units in the conversion factors must cancel to give the correct unit for the answer.
What is wrong with the following setup? 1.4 day x 1 day x hr
24 hr min
Units = day2/min is not the unit needed
Units don’t cancel properly.

22. Learning Check
A bucket contains 4.65 L of water. How many gallons of water is that?
Unit plan: L > qt > gallon
Equalities: 1.06 qt = 1 L
1 gal = 4 qt

23. 1.5 Measurement in Scientific Study
Note: Measurements of Time is not a base 10 system: h = 60 min = 3600 s

24. Metric and SI Prefixes (Table 2)

25. Common SI-English Equivalent Quantities
Table 1.9

26. Learning Check
For each of the following, indicate whether the unit describes 1) length 2) mass or 3) volume.
____ A. A bag of tomatoes is 4.6 kg.
____ B. A person is 2.0 m tall.
____ C. A medication contains 0.50 g aspirin.
____ D. A bottle contains 1.5 L of water.

27. Measuring Length and Volume
The meter (m) is the standard measure of length or distance in both the SI and the metric system.
Volume is the amount of space occupied by an object. A volume of a CUBE can be described as a (length)3.
The SI unit for volume is the cubic meter (m3).
The metric unit for volume is liter (dm3).
Note: 1 mL = 1 cm3

28. Density
Density (a measure of compactness) relates the mass of an object to its volume. Density is usually expressed in units of grams per cubic centimeter (g/cm3) for solids, and grams per milliliter (g/mL) for liquids.
Mass (g)
Density =
Volume (mL or cm3)

29. Problems
A piece of copper has a mass of g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cm3).
Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg in grams?

30. Temperature TF = 1.8 TC + 32 TK = TC + 273.15 0C
Temperature is a measure of how hot or cold an object is compared to another object.
Heat flows from the object with a higher temperature to the object with a lower temperature.
Temperature is measured using a thermometer in Celsius, Kelvin, or Farenheit scales
TF = 1.8 TC 
TK = TC C
Lowest possible temperature: C = 0.00 K

31. Temperature Scales 100 oF 38 oC 311 K Normal body tempe-rature
A person with hypothermia has a body temperature of 34.8°C. What is that temperature in °F? in K? oF oC K

32. 1.6 Uncertainty in Measurement
An exact number is obtained
When objects are counted
Counting objects
2 soccer balls
4 pizzas
From numbers in a defined relationship.
Defined relationships
1 foot = 12 inches
1 meter = 100 cm

33. Exact Numbers vs. Measured Numbers
A measuring tool
Is used to determine a quantity such as height or the mass of an object.
Provides numbers for a measurement that are called measured numbers.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

34. Learning Check Classify each of the following as exact (E) or
measured (M) numbers.
A. Gold melts at 1064°C.
B. 1 yard = 3 feet
C. The diameter of a red blood cell is 6 x 10-4 cm.
D. There are 6 hats on the shelf.
E. A can of soda contains 355 mL of soda.

35. Significant Figures

36. Determining Which Digits are Significant
Every experimental measurement has a degree of uncertainty.
The volume, V, at right is certain in the 10’s place, 10mL < V < 20mL
The 1’s digit is also certain, 17mL < V < 18mL
A best guess is needed for the tenths place.

37. Reading a Meter Stick
The markings on the meter stick at the end of the blue line are read as
The first digit 2 plus the second digit 2.7
The last digit is obtained by estimating.
The end of the line might be estimated between 2.7–2.8 as half-way (0.5) or a little more (0.6), which gives a reported length of 2.75 cm or 2.76 cm.

38. Known + Estimated Digits
Significant figures obtained from a measurement include all of the known digits plus the estimated digit.
In the length reported as 2.76 cm,
The digits 2 and 7 are certain (known).
The last digit 6 was estimated (uncertain).
All three digits (2.76) are significant, including the estimated digit.

39. Learning Check What is the length of the red line? 1) 9.0 cm

40. Zero as the last digit in Measured Number
For this measurement, the first and second known digits are 4.7
Because the line ends on a mark, the estimated digit in the hundredths place is 0.
This measurement is reported as 4.70 cm.

41. Learning Check
A. State the number of significant figures in each of the following measurements:
0.030 m L g 2.80 m
B. Which answer(s) contains 3 significant figures?
1) ) ) x 103
C. All the zeros are significant in
1) ) ) x 103
D. The number of significant figures in 5.80 x 102 is
1) one 2) two 3) three

42. Rounding Off Calculated Answers
In calculations,
Answers must have the same number of significant figures as the measured numbers.
When the first digit dropped is 4 or less,
the retained numbers remain the same.
To round to 3 significant figures
drop the digits 32 = 45.8
When the first digit dropped is 5 or greater,
the last retained digit is increased by 1.
To round to 2 significant figures
drop the digits 884 = 2.5 (increase by 0.1)

43. Multiplication and Division
When multiplying or dividing use
The same number of significant figures as the measurement with the fewest significant digits.
Rounding rules or adding zeros are applied to obtain the correct number of significant figures.
Example:
x = = (rounded)
4 SF SF calculator SF

44. Learning Check Give an answer for the following with the correct
number of significant figures:
A x =
1) ) )
B ÷ =
1) ) ) 60
C x =
x 0.060
1) ) )

45. Adding Significant Zeros
Sometimes a calculated answer requires more significant digits. Then one or more zeros must be added.
Example: When the calculated numbers should have 3 significant figures,
Calculated answer Zeros added to
give 3 significant figures

46. Learning Check
Give the answers for the following calculations with correct numbers of significant figures:
A cm x 2.00 cm
B g / 2 bags

47. Addition and Subtraction
When adding or subtracting use
The same number of decimal places as the measurement with the fewest decimal places.
Rounding rules to adjust the number of digits in the answer.
one decimal place
two decimal places
1.84 calculated answer
1.8 answer with one decimal place

48. Learning Check
For each calculation, give the answer with correct number of significant figures.
A =
1) ) )
B =
1) ) ) 40.7

49. Exact and Measured Numbers in Equalities
Equalities between units of
The same system are definitions and use exact numbers.
Different systems (metric and U.S.) use measured numbers and count as significant figures.
Example: 1ft = 12 in. (exact)
1 in. = 2.54 cm (measured)

50. Precision and Accuracy