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Chapter One:

CHEMICALFOUNDATIONS

1–1, 11–1, 2

Atoms vs. Molecules

Relative abundances of elements

1–1, 4

A Chemical Reaction

The Various Parts of the Scientific Method

Notes 1.1, 4 – 1.2

Hypothesis vs. Theory vs. Law

• A hypothesis is a possible explanation for an observation. It comes before the experiment, and the experiment is designed to test the hypothesis.

• A theory, which can be thought of as a model, is an attempt to explain whysomething happens. It is an interpretation or explanation of a natural phenomenon.

• A law summarizes what happens, usually as a math equation.

Notes 1.2 Practice

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The Fundamental SI Units

Physical Quantity Name of Unit AbbreviationMass kilogram kg

Length meter m

Time second s

Temperature kelvin KElectric current ampere A

Amount of substance mole mol

Luminous intensity candela cd

Notes 1.3 – 1.3A

Memorize!

Mass vs. Weight

1–3, 3 & Practice

Uncertainty in Measurement

• A measurement always has some degree of uncertainty.

• A digit that must be estimated is called the uncertain digit.

• Values in science are reported with the appropriate number of significant figures to reflect uncertainty of measurement.

1–4, 1

The Difference Between Precision and Accuracy

Accuracy – how close is measured value to true value

Precision – how measurements agree with each other

Random error – error is randomly high or low

Systematic error – error occurs in same direction 1.4, 2-5

Common Types of Laboratory Equipment Used to Measure Liquid Volume

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Uncertainty in Measurement Activity

• Measure out a 25 ml aliquot of a water– One student use

100-ml graduated cylinder

– One student use 25-ml glass pipet

• Knowing 1 ml of water weights 1.00 g at room temperature, weigh samples for accuracy.

• Which method is more reliable?

Notes 1.5

Rules for Counting Significant Figures

• Nonzero integers always count as significant figures.– 3,456 has 4 sig figs.

• Leading zeros do not count as significant figures.– 0.048 has 2 sig figs.

Rules for Counting Significant Figures

• Captive zeros always count as significant figures.– 16.07 has 4 sig figs.

• Trailing zeros are significant only if the number contains a decimal point.– 9.300 has 4 sig figs– 150 has 2 sig figs.

Rules for Counting Significant Figures

• Exact numbers have an infinite number of significant figures.– 1 inch = 2.54 cm, exactly– 23 students in the room

Practice 1.5 A

Rules for Significant Figures in Mathematical Operations

• For multiplication or division, the number of sig figs in the result is the same as the number in the least precisemeasurement used in the calculation.

• For addition or subtraction, the result has the same number of decimal places as the least precise measurement used in the calculation

Recall Order of Operations

1. Parenthesis2. Exponents and logs

3. Multiplication & division4. Addition & Subtraction

You will often have to solve problems where there is a combination of mathematical operations.

Practice 1.5 B

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Measurement of Volume using a Buret

The volume is read at the bottom of the liquid curve called the meniscus.

What value would report?

Practice 1.5 C

You have water in each graduated cylinder shown. You then add both samples to a beaker. How would you write the number describing the total volume? What limits the precision of this number?

Practice 1.5 C

Dimensional Analysis

• Why use dimensional analysis?

• Using conversion factors• Remember to cube length

units when doing volume conversions.

Notes 1.6

1 dm3 = 1 L = 1000 cm3

1 ml = 1 cm3 = 1 g H2O

Review Dimensional Analysis

• Convert 6.3 km to in

• Convert 1.7 m3 to ml

• Convert 186,000 mi/s to cm/yr

Practice 1.6 A & B

Notes 1.7

The Three Major Temperature Scales

212°F – 32 = 180°F

100°C – 0 = 100°C

180°F = 9°F 100°C 5°C

Figure 1.12 Normal Body Temperature

A normal body temperature is 98.6 °F.

What is this temperature in °C?

What is this temperature in K?

Practice 1.7

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Density

• Density = mass / volume– Practice rearranging equation to find other terms.– Remember you may have to use conversions to

attain desired units.– Density commonly expressed as g/ml or g/cm3

– Intensive property

Notes 1.8

Table 1.5 Densities of Various Common Substances* at 20°C

Practice 1.8 A & B

Practice 1.8 A• How many pounds would 1.00 liter of mercury weigh?

Practice 1.8 B• An unknown metal having a mass of 287.8 g was

added to a graduated cylinder that contained 31.47 ml of water. After the addition of the metal, the water level rose to 56.85 ml. Identify the unknown metal.

Matter

• Chemistry is the study of matter and the changes it undergoes.

• Matter is defined as anything occupying space and having mass.

The Three States of Water Solids

• The state of matter in which the particles occupy fixed positions, giving the substance a definite shape.– The particles are held in these

positions by bonds. – The strengths of these types of

bonds (ionic, covalent, and intermolecular) are different and so, therefore, are the mechanical properties of different solids.

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Liquids

• The state of matter in which the particles of a substance are loosely bound by intermolecular forces.– The weakness of these forces

permits movement of the particles and consequently liquids can change their shape within a fixed volume.

– The liquid state lacks the order of the solid state.

• Amorphous materials, such as glass, in which the particles are disordered and can move relative to each other can be classified as liquids.

Gases

• The state of matter in which the forces of attraction between the particles of a substance are small.– The particles have freedom of

movement and gases, therefore have no fixed shape or volume.

– The particles are in a continual state of motion and are continually colliding with each other and with the walls of the containing vessel.

Note spelling

The Organization of Matter

Heterogeneous – not uniform throughout

Homogeneous – uniform throughout

(homogeneous liquids are called solutions)

The Organization of Matter

Mercury and Iodine Combine to Form Mercuric Iodide

The Organization of Matter

lemonade

H2, O2, CH2O, C6H12O6

lemon juice,sugar, water

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The Organization of Matter Simple Laboratory Distillation ApparatusDistillation = the process of boiling a liquid and condensing the vapor.

Filtration

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Filtration = the process removing suspended particles from a fluid by passing or forcing the fluid through a porous material (the filter).

Filtrate = the fluid that passed through the filter.

Figure 1.15a A Line of the Mixture to be Separated is Placed at One End of a Sheet

Figure 1.15b The Paper Acts as a Wick to Draw up the Liquid

Figure 1.15c Component with the Weakest Attraction for the Paper Travels Faster

Chromatography = the sample to be separated is carried by the mobile phase through the stationary phase. Different components of the mixture are absorbed or dissolved to different extents on the stationary phase and are thus separated.