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Chapter one lecture slides for AP Chemistry Matter and Measurement

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Page 1: Chapter 1 Lecture- Matter & Measurement

Chemistry

Page 2: Chapter 1 Lecture- Matter & Measurement

Chemistry

• is the study of properties of materials and changes that they undergo.

Page 3: Chapter 1 Lecture- Matter & Measurement

Chemistry

• is the study of properties of materials and changes that they undergo. • can be applied to all aspects of life (e.g., development of pharmaceuticals, leaf color change in fall, etc.).

Page 4: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Page 5: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Page 6: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter:

Page 7: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter: • is the physical material of the universe.

Page 8: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter: • is the physical material of the universe.• has mass.

Page 9: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter: • is the physical material of the universe.• has mass.• occupies space.

Page 10: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter: • is the physical material of the universe.• has mass.• occupies space. • ~100 elements constitute all matter.

Page 11: Chapter 1 Lecture- Matter & Measurement

The Atomic and Molecular Perspective of Chemistry

Chemistry involves the study of the properties and the behavior of matter.

Matter: • is the physical material of the universe.• has mass.• occupies space. • ~100 elements constitute all matter.• A property is any characteristic that allows us to

recognize a particular type of matter and to distinguish it from other types of matter.

Page 12: Chapter 1 Lecture- Matter & Measurement

Elements

Page 13: Chapter 1 Lecture- Matter & Measurement

Elements

Page 14: Chapter 1 Lecture- Matter & Measurement

Elements

• are made up of unique atoms, the building

blocks of matter.

Page 15: Chapter 1 Lecture- Matter & Measurement

Elements

• are made up of unique atoms, the building

blocks of matter. • Names of the elements are derived from a

wide variety of sources (e.g., Latin or Greek, mythological characters, names of people or places).

Page 16: Chapter 1 Lecture- Matter & Measurement

Elements

• are made up of unique atoms, the building

blocks of matter. • Names of the elements are derived from a

wide variety of sources (e.g., Latin or Greek, mythological characters, names of people or places).

• Memorize element symbols

Page 17: Chapter 1 Lecture- Matter & Measurement

Molecules

Page 18: Chapter 1 Lecture- Matter & Measurement

Molecules

Page 19: Chapter 1 Lecture- Matter & Measurement

Molecules

• are combinations of atoms held together in

specific shapes.

Page 20: Chapter 1 Lecture- Matter & Measurement

Molecules

• are combinations of atoms held together in

specific shapes.• Macroscopic (observable) properties of matter

relate to submicroscopic realms of atoms.

Page 21: Chapter 1 Lecture- Matter & Measurement

Molecules

• are combinations of atoms held together in

specific shapes.• Macroscopic (observable) properties of matter

relate to submicroscopic realms of atoms.• Properties relate to composition (types of atoms

present) and structure (arrangement of atoms) present.

Page 22: Chapter 1 Lecture- Matter & Measurement

1.2 Classifications of Matter

Matter is classified by state (solid, liquid or gas) or by composition (element, compound or mixture).

Page 23: Chapter 1 Lecture- Matter & Measurement

States of Matter

Page 24: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Page 25: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Page 26: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Properties described on the macroscopic level:

Page 27: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Properties described on the macroscopic level:• gas (vapor): no fixed volume or shape, conforms

to shape of container, compressible.

Page 28: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Properties described on the macroscopic level:• gas (vapor): no fixed volume or shape, conforms

to shape of container, compressible.• liquid: volume independent of container, no fixed

shape, incompressible.

Page 29: Chapter 1 Lecture- Matter & Measurement

States of Matter

Solids, liquids and gases are the three forms of matter called the states of matter.

Properties described on the macroscopic level:• gas (vapor): no fixed volume or shape, conforms

to shape of container, compressible.• liquid: volume independent of container, no fixed

shape, incompressible.• solid: volume and shape independent of

container, rigid, incompressible.

Page 30: Chapter 1 Lecture- Matter & Measurement

States of Matter

Page 31: Chapter 1 Lecture- Matter & Measurement

States of Matter

Properties described on the molecular level:

Page 32: Chapter 1 Lecture- Matter & Measurement

States of Matter

Properties described on the molecular level:• gas: molecules far apart, move at high

speeds, collide often.

Page 33: Chapter 1 Lecture- Matter & Measurement

States of Matter

Properties described on the molecular level:• gas: molecules far apart, move at high

speeds, collide often.• liquid: molecules closer than gas, move

rapidly but can slide over each other.

Page 34: Chapter 1 Lecture- Matter & Measurement

States of Matter

Properties described on the molecular level:• gas: molecules far apart, move at high

speeds, collide often.• liquid: molecules closer than gas, move

rapidly but can slide over each other.• solid: molecules packed closely in definite

arrangements.

Page 35: Chapter 1 Lecture- Matter & Measurement

Pure Substances

Page 36: Chapter 1 Lecture- Matter & Measurement

Pure Substances

Pure substances:

Page 37: Chapter 1 Lecture- Matter & Measurement

Pure Substances

Pure substances: • are matter with fixed compositions and

distinct proportions.

Page 38: Chapter 1 Lecture- Matter & Measurement

Pure Substances

Pure substances: • are matter with fixed compositions and

distinct proportions.• are elements (cannot be decomposed into

simpler substances, i.e. only one kind of atom) or compounds (consist of two or more elements).

Page 39: Chapter 1 Lecture- Matter & Measurement

Mixtures

Page 40: Chapter 1 Lecture- Matter & Measurement

Mixtures

• are a combination of two or more pure substances.

Page 41: Chapter 1 Lecture- Matter & Measurement

Mixtures

• are a combination of two or more pure substances.

• Each substance retains its own identity.

Page 42: Chapter 1 Lecture- Matter & Measurement

Elements

Page 43: Chapter 1 Lecture- Matter & Measurement

Elements

• There are 116 known elements.

Page 44: Chapter 1 Lecture- Matter & Measurement

Elements

• There are 116 known elements.• They vary in abundance.

Page 45: Chapter 1 Lecture- Matter & Measurement

Elements

• There are 116 known elements.• They vary in abundance.• Each is given a unique name and is

abbreviated by a chemical symbol.

Page 46: Chapter 1 Lecture- Matter & Measurement

Elements

• There are 116 known elements.• They vary in abundance.• Each is given a unique name and is

abbreviated by a chemical symbol.• they are organized in the periodic table.

Page 47: Chapter 1 Lecture- Matter & Measurement

Elements

• There are 116 known elements.• They vary in abundance.• Each is given a unique name and is

abbreviated by a chemical symbol.• they are organized in the periodic table.• Each is given a one- or two-letter symbol

derived from its name.

Page 48: Chapter 1 Lecture- Matter & Measurement

Compounds

Page 49: Chapter 1 Lecture- Matter & Measurement

Compounds

• Compounds are combinations of elements.

Page 50: Chapter 1 Lecture- Matter & Measurement

Compounds

• Compounds are combinations of elements. Example: The compound H2O is a

combination of the elements H and O.

Page 51: Chapter 1 Lecture- Matter & Measurement

Compounds

• Compounds are combinations of elements. Example: The compound H2O is a

combination of the elements H and O.• The opposite of compound formation is

decomposition.

Page 52: Chapter 1 Lecture- Matter & Measurement

Compounds

• Compounds are combinations of elements. Example: The compound H2O is a

combination of the elements H and O.• The opposite of compound formation is

decomposition.• Compounds have different properties than their

component elements (e.g., water is liquid, but hydrogen and oxygen are both gases at the same temperature and pressure).

Page 53: Chapter 1 Lecture- Matter & Measurement

Law of Constant (Definite) Proportions

Page 54: Chapter 1 Lecture- Matter & Measurement

Law of Constant (Definite) Proportions

(Proust): A compound always consists of the same combination of elements (e.g., water is always 11% H and 89% O).

Page 55: Chapter 1 Lecture- Matter & Measurement
Page 56: Chapter 1 Lecture- Matter & Measurement

Mixtures

Page 57: Chapter 1 Lecture- Matter & Measurement

Mixtures

• A mixture is a combination of two or more pure substances.

Page 58: Chapter 1 Lecture- Matter & Measurement

Mixtures

• A mixture is a combination of two or more pure substances.

• Each substance retains its own identity; each substance is a component of the mixture.

Page 59: Chapter 1 Lecture- Matter & Measurement

Mixtures

• A mixture is a combination of two or more pure substances.

• Each substance retains its own identity; each substance is a component of the mixture.

• Mixtures have variable composition.

Page 60: Chapter 1 Lecture- Matter & Measurement

Mixtures

• A mixture is a combination of two or more pure substances.

• Each substance retains its own identity; each substance is a component of the mixture.

• Mixtures have variable composition.• Heterogeneous mixtures do not have uniform

composition, properties, and appearance, e.g., sand.

Page 61: Chapter 1 Lecture- Matter & Measurement

Mixtures

• A mixture is a combination of two or more pure substances.

• Each substance retains its own identity; each substance is a component of the mixture.

• Mixtures have variable composition.• Heterogeneous mixtures do not have uniform

composition, properties, and appearance, e.g., sand.

• Homogeneous mixtures are uniform throughout, e.g., air; they are solutions.

Page 62: Chapter 1 Lecture- Matter & Measurement
Page 63: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Page 64: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of MatterEach substance has a unique set of physical and

chemical properties.

Page 65: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of MatterEach substance has a unique set of physical and

chemical properties.• Physical properties are measured without

changing the substance (e.g., color, density, odor, melting point, etc.).

Page 66: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of MatterEach substance has a unique set of physical and

chemical properties.• Physical properties are measured without

changing the substance (e.g., color, density, odor, melting point, etc.).

• Chemical properties describe how substances react or change to form different substances (e.g., hydrogen burns in oxygen).

Page 67: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Page 68: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Properties may be categorized as intensive or extensive.

Page 69: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Properties may be categorized as intensive or extensive.

• Intensive properties do not depend on the amount of substance present (e.g., temperature, melting point etc.).

Page 70: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Properties may be categorized as intensive or extensive.

• Intensive properties do not depend on the amount of substance present (e.g., temperature, melting point etc.).

• Extensive properties depend on the quantity of substance present (e.g., mass, volume etc.).

Page 71: Chapter 1 Lecture- Matter & Measurement

1.3 Properties of Matter

Properties may be categorized as intensive or extensive.

• Intensive properties do not depend on the amount of substance present (e.g., temperature, melting point etc.).

• Extensive properties depend on the quantity of substance present (e.g., mass, volume etc.).

• Intensive properties give an idea of the composition of a substance whereas extensive properties give an indication of the quantity of substance present.

Page 72: Chapter 1 Lecture- Matter & Measurement

Physical and Chemical Changes

Page 73: Chapter 1 Lecture- Matter & Measurement

Physical and Chemical Changes

• Physical change: substance changes physical appearance without altering its identity (e.g., changes of state).

Page 74: Chapter 1 Lecture- Matter & Measurement

Physical and Chemical Changes

• Physical change: substance changes physical appearance without altering its identity (e.g., changes of state).

• Chemical change (or chemical reaction): substance transforms into a chemically different substance (i.e. identity changes, e.g., decomposition of water, explosion of nitrogen triiodide).

Page 75: Chapter 1 Lecture- Matter & Measurement

Separation of Mixtures

Page 76: Chapter 1 Lecture- Matter & Measurement

Separation of Mixtures

Key: separation techniques exploit differences in properties of the components.

Page 77: Chapter 1 Lecture- Matter & Measurement

Separation of Mixtures

Key: separation techniques exploit differences in properties of the components.

• Filtration: remove solid from liquid.

Page 78: Chapter 1 Lecture- Matter & Measurement

Separation of Mixtures

Key: separation techniques exploit differences in properties of the components.

• Filtration: remove solid from liquid. • Distillation: boil off one or more

components of the mixture.

Page 79: Chapter 1 Lecture- Matter & Measurement

Separation of Mixtures

Key: separation techniques exploit differences in properties of the components.

• Filtration: remove solid from liquid. • Distillation: boil off one or more

components of the mixture. • Chromatography: exploit solubility of

components.

Page 80: Chapter 1 Lecture- Matter & Measurement

The Scientific Method

Page 81: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science.

Page 82: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science. • Collect data (observe, experiment, etc.).

Page 83: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science. • Collect data (observe, experiment, etc.). • Look for patterns, try to explain them, and

develop a hypothesis or tentative explanation.

Page 84: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science. • Collect data (observe, experiment, etc.). • Look for patterns, try to explain them, and

develop a hypothesis or tentative explanation. • Test hypothesis, then refine it.

Page 85: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science. • Collect data (observe, experiment, etc.). • Look for patterns, try to explain them, and

develop a hypothesis or tentative explanation. • Test hypothesis, then refine it. • Bring all information together into a scientific

law (concise statement or equation that summarizes tested hypotheses).

Page 86: Chapter 1 Lecture- Matter & Measurement

The Scientific MethodThe scientific method provides guidelines for the

practice of science. • Collect data (observe, experiment, etc.). • Look for patterns, try to explain them, and

develop a hypothesis or tentative explanation. • Test hypothesis, then refine it. • Bring all information together into a scientific

law (concise statement or equation that summarizes tested hypotheses).

• Bring hypotheses and laws together into a theory. A theory should explain general principles.

Page 87: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 88: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 89: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 90: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 91: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 92: Chapter 1 Lecture- Matter & Measurement

Steps in the Scientific Method

1.3

Page 93: Chapter 1 Lecture- Matter & Measurement

Units of Measurement

Page 94: Chapter 1 Lecture- Matter & Measurement

SI Units

Page 95: Chapter 1 Lecture- Matter & Measurement

SI Units

• Système International d’Unités

Page 96: Chapter 1 Lecture- Matter & Measurement

SI Units

• Système International d’Unités• Uses a different base unit for each quantity

Page 97: Chapter 1 Lecture- Matter & Measurement

Metric System

Prefixes convert the base units into units that are appropriate for the item being measured.

Page 98: Chapter 1 Lecture- Matter & Measurement

PRACTICE EXERCISE(a) What decimal fraction of a second is

a picosecond, ps? (b) Express the measurement 6.0 ×

103 m using a prefix to replace the power of ten.

(c) Use exponential notation to express 3.76 mg in grams.

Page 99: Chapter 1 Lecture- Matter & Measurement

PRACTICE EXERCISE(a) What decimal fraction of a second is

a picosecond, ps? (b) Express the measurement 6.0 ×

103 m using a prefix to replace the power of ten.

(c) Use exponential notation to express 3.76 mg in grams.

Answers: (a) 10–12 second, (b) 6.0 km, (c) 3.76 × 10–3 g

Page 100: Chapter 1 Lecture- Matter & Measurement

Volume

Page 101: Chapter 1 Lecture- Matter & Measurement

Volume

• The most commonly used metric units for volume are the liter (L) and the milliliter (mL).

Page 102: Chapter 1 Lecture- Matter & Measurement

Volume

• The most commonly used metric units for volume are the liter (L) and the milliliter (mL).□ A liter is a cube 1 dm

long on each side.

Page 103: Chapter 1 Lecture- Matter & Measurement

Volume

• The most commonly used metric units for volume are the liter (L) and the milliliter (mL).□ A liter is a cube 1 dm

long on each side.□ A milliliter is a cube 1 cm

long on each side.

Page 104: Chapter 1 Lecture- Matter & Measurement

Temperature:

A measure of the average kinetic energy of the particles in a sample.

Page 105: Chapter 1 Lecture- Matter & Measurement

Temperature

Page 106: Chapter 1 Lecture- Matter & Measurement

Temperature• In scientific

measurements, the Celsius and Kelvin scales are most often used.

Page 107: Chapter 1 Lecture- Matter & Measurement

Temperature• In scientific

measurements, the Celsius and Kelvin scales are most often used.

• The Celsius scale is based on the properties of water.

Page 108: Chapter 1 Lecture- Matter & Measurement

Temperature• In scientific

measurements, the Celsius and Kelvin scales are most often used.

• The Celsius scale is based on the properties of water.□ 0°C is the freezing point

of water.

Page 109: Chapter 1 Lecture- Matter & Measurement

Temperature• In scientific

measurements, the Celsius and Kelvin scales are most often used.

• The Celsius scale is based on the properties of water.□ 0°C is the freezing point

of water.□ 100°C is the boiling

point of water.

Page 110: Chapter 1 Lecture- Matter & Measurement

Temperature

Page 111: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Kelvin is the SI unit of temperature.

Page 112: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Kelvin is the SI unit of temperature.

• It is based on the properties of gases.

Page 113: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Kelvin is the SI unit of temperature.

• It is based on the properties of gases.

• There are no negative Kelvin temperatures.

Page 114: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Kelvin is the SI unit of temperature.

• It is based on the properties of gases.

• There are no negative Kelvin temperatures.

• K = °C + 273.15

Page 115: Chapter 1 Lecture- Matter & Measurement

Temperature

Page 116: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Fahrenheit scale is not used in scientific measurements.

Page 117: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Fahrenheit scale is not used in scientific measurements.

• °F = 9/5(°C) + 32

Page 118: Chapter 1 Lecture- Matter & Measurement

Temperature

• The Fahrenheit scale is not used in scientific measurements.

• °F = 9/5(°C) + 32• °C = 5/9(°F − 32)

Page 119: Chapter 1 Lecture- Matter & Measurement

Density:

Physical property of a substance

Page 120: Chapter 1 Lecture- Matter & Measurement

Density:

Physical property of a substance

d= mV

Page 121: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

(a) Calculate the density of mercury if 1.00 × 102 g occupies a volume of 7.36 cm3.

Page 122: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

(a) Calculate the density of mercury if 1.00 × 102 g occupies a volume of 7.36 cm3.

Solution (a) We are given mass and volume, so Equation 1.3 yields

Page 123: Chapter 1 Lecture- Matter & Measurement

(b) Calculate the volume of 65.0 g of the liquid methanol (wood alcohol) if its density is 0.791 g/mL.

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

Page 124: Chapter 1 Lecture- Matter & Measurement

(b) Calculate the volume of 65.0 g of the liquid methanol (wood alcohol) if its density is 0.791 g/mL.

Solution (b) Solving Equation 1.3 for volume and then using the given mass and density gives

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

Page 125: Chapter 1 Lecture- Matter & Measurement

(c) What is the mass in grams of a cube of gold (density = 19.32 g/ cm3) if the length of the cube is 2.00 cm?

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

Page 126: Chapter 1 Lecture- Matter & Measurement

(c) What is the mass in grams of a cube of gold (density = 19.32 g/ cm3) if the length of the cube is 2.00 cm?

Solution

(c) We can calculate the mass from the volume of the cube and its density. The volume of a cube is given by its length cubed:

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

Page 127: Chapter 1 Lecture- Matter & Measurement

(c) What is the mass in grams of a cube of gold (density = 19.32 g/ cm3) if the length of the cube is 2.00 cm?

Solution

(c) We can calculate the mass from the volume of the cube and its density. The volume of a cube is given by its length cubed:

Solving Equation 1.3 for mass and substituting the volume and density of the cube, we have

SAMPLE EXERCISE 1.4 Determining Density and Using Density to Determine Volume or Mass

Page 128: Chapter 1 Lecture- Matter & Measurement

Uncertainty in Measurements

Different measuring devices have different uses and different degrees of accuracy.

Page 129: Chapter 1 Lecture- Matter & Measurement

PRACTICE EXERCISEA balance has a precision of ± 0.001 g. A sample that has a mass of about 25 g is placed on this balance. How many significant figures should be reported for this measurement?

Page 130: Chapter 1 Lecture- Matter & Measurement

PRACTICE EXERCISEA balance has a precision of ± 0.001 g. A sample that has a mass of about 25 g is placed on this balance. How many significant figures should be reported for this measurement?

Answer: five, as in the measurement 24.995 g

Page 131: Chapter 1 Lecture- Matter & Measurement

Uncertainty in Measurement

Page 132: Chapter 1 Lecture- Matter & Measurement

Significant Figures

Page 133: Chapter 1 Lecture- Matter & Measurement

Significant Figures

• The term significant figures refers to digits that were measured.

Page 134: Chapter 1 Lecture- Matter & Measurement

Significant Figures

• The term significant figures refers to digits that were measured.

• When rounding calculated numbers, we pay attention to significant figures so we do not overstate the accuracy of our answers.

Page 135: Chapter 1 Lecture- Matter & Measurement

Significant Figures

Page 136: Chapter 1 Lecture- Matter & Measurement

Significant Figures

1. All nonzero digits are significant.

Page 137: Chapter 1 Lecture- Matter & Measurement

Significant Figures

1. All nonzero digits are significant.2. Zeroes between two significant figures

are themselves significant.

Page 138: Chapter 1 Lecture- Matter & Measurement

Significant Figures

1. All nonzero digits are significant.2. Zeroes between two significant figures

are themselves significant.3. Zeroes at the beginning of a number

are never significant.

Page 139: Chapter 1 Lecture- Matter & Measurement

Significant Figures

1. All nonzero digits are significant.2. Zeroes between two significant figures

are themselves significant.3. Zeroes at the beginning of a number

are never significant.4. Zeroes at the end of a number are

significant if a decimal point is written in the number.

Page 140: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.6 Determining the Number of Significant Figures in a Measurement

How many significant figures are in each of the following numbers (assume that each number is a measured quantity): (a) 4.003, (b) 6.023 × 1023, (c) 5000?

Page 141: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.6 Determining the Number of Significant Figures in a Measurement

How many significant figures are in each of the following numbers (assume that each number is a measured quantity): (a) 4.003, (b) 6.023 × 1023, (c) 5000?

Solution (a) Four; the zeros are significant figures. (b) Four; the exponential term does not add to the number of significant figures.

Page 142: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.6 Determining the Number of Significant Figures in a Measurement

How many significant figures are in each of the following numbers (assume that each number is a measured quantity): (a) 4.003, (b) 6.023 × 1023, (c) 5000?

Solution (a) Four; the zeros are significant figures. (b) Four; the exponential term does not add to the number of significant figures. (c) One. We assume that the zeros are not significant when there is no decimal point shown. If the number has more significant figures, a decimal point should be employed or the number written in exponential notation. Thus, 5000. has four significant figures, whereas 5.00 × 103 has three.

Page 143: Chapter 1 Lecture- Matter & Measurement

Significant Figures

Page 144: Chapter 1 Lecture- Matter & Measurement

Significant Figures

• When addition or subtraction is performed, answers are rounded to the least significant decimal place.

Page 145: Chapter 1 Lecture- Matter & Measurement

Significant Figures

• When addition or subtraction is performed, answers are rounded to the least significant decimal place.

• When multiplication or division is performed, answers are rounded to the number of digits that corresponds to the least number of significant figures in any of the numbers used in the calculation.

Page 146: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.7 Determining the Number of Significant Figures in a Calculated Quantity

The width, length, and height of a small box are 15.5 cm, 27.3 cm, and 5.4 cm, respectively. Calculate the volume of the box, using the correct number of significant figures in your answer.

Page 147: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.7 Determining the Number of Significant Figures in a Calculated Quantity

The width, length, and height of a small box are 15.5 cm, 27.3 cm, and 5.4 cm, respectively. Calculate the volume of the box, using the correct number of significant figures in your answer.

Solution In multiplication & division, count sig figs.In addition & subtraction, count decimal places.

Page 148: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.7 Determining the Number of Significant Figures in a Calculated Quantity

The width, length, and height of a small box are 15.5 cm, 27.3 cm, and 5.4 cm, respectively. Calculate the volume of the box, using the correct number of significant figures in your answer.

Solution In multiplication & division, count sig figs.In addition & subtraction, count decimal places.

Page 149: Chapter 1 Lecture- Matter & Measurement

A gas at 25°C fills a container whose volume is 1.05 × 103

cm3. The container plus gas have a mass of 837.6 g. The container, when emptied of all gas, has a mass of 836.2 g. What is the density of the gas at 25°C?

SAMPLE EXERCISE 1.8 Determining the Number of Significant Figures in a Calculated Quantity

Page 150: Chapter 1 Lecture- Matter & Measurement

A gas at 25°C fills a container whose volume is 1.05 × 103

cm3. The container plus gas have a mass of 837.6 g. The container, when emptied of all gas, has a mass of 836.2 g. What is the density of the gas at 25°C?

Solution

To calculate the density, we must know both the mass and the volume of the gas. mass of the gas = full - empty container: (837.6 – 836.2) g = 1.4 g

SAMPLE EXERCISE 1.8 Determining the Number of Significant Figures in a Calculated Quantity

Page 151: Chapter 1 Lecture- Matter & Measurement

A gas at 25°C fills a container whose volume is 1.05 × 103

cm3. The container plus gas have a mass of 837.6 g. The container, when emptied of all gas, has a mass of 836.2 g. What is the density of the gas at 25°C?

Solution

To calculate the density, we must know both the mass and the volume of the gas. mass of the gas = full - empty container: (837.6 – 836.2) g = 1.4 g

SAMPLE EXERCISE 1.8 Determining the Number of Significant Figures in a Calculated Quantity

Page 152: Chapter 1 Lecture- Matter & Measurement

Accuracy versus Precision

Page 153: Chapter 1 Lecture- Matter & Measurement

Accuracy versus Precision

• Accuracy refers to the proximity of a measurement to the true value of a quantity.

Page 154: Chapter 1 Lecture- Matter & Measurement

Accuracy versus Precision

• Accuracy refers to the proximity of a measurement to the true value of a quantity.

• Precision refers to the proximity of several measurements to each other.

Page 155: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.9 Converting Units

If a woman has a mass of 115 lb, what is her mass in grams? (Use the relationships between units given on the back inside cover of the text.)

Page 156: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.9 Converting Units

If a woman has a mass of 115 lb, what is her mass in grams? (Use the relationships between units given on the back inside cover of the text.)

Page 157: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.9 Converting Units

If a woman has a mass of 115 lb, what is her mass in grams? (Use the relationships between units given on the back inside cover of the text.)

Solution Because we want to change from lb to g, we look for a relationship between these units of mass. From the back inside cover we have 1 lb = 453.6 g. In order to cancel pounds and leave grams, we write the conversion factor with grams in the numerator and pounds in the denominator:

Page 158: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.9 Converting Units

If a woman has a mass of 115 lb, what is her mass in grams? (Use the relationships between units given on the back inside cover of the text.)

Solution Because we want to change from lb to g, we look for a relationship between these units of mass. From the back inside cover we have 1 lb = 453.6 g. In order to cancel pounds and leave grams, we write the conversion factor with grams in the numerator and pounds in the denominator:

Page 159: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.9 Converting Units

If a woman has a mass of 115 lb, what is her mass in grams? (Use the relationships between units given on the back inside cover of the text.)

Solution Because we want to change from lb to g, we look for a relationship between these units of mass. From the back inside cover we have 1 lb = 453.6 g. In order to cancel pounds and leave grams, we write the conversion factor with grams in the numerator and pounds in the denominator:

The answer can be given to only three significant figures, the number of significant figures in 115 lb.

Page 160: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.10 Converting Units Using Two or More Conversion Factors

The average speed of a nitrogen molecule in air at 25°C is 515 m/s. Convert this speed to miles per hour.

Page 161: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.10 Converting Units Using Two or More Conversion Factors

The average speed of a nitrogen molecule in air at 25°C is 515 m/s. Convert this speed to miles per hour.

Solution On the back inside cover of the book, we find that 1 mi = 1.6093 km1 km = 103 m60 s = 1 min 60 min = 1 hr

Page 162: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.10 Converting Units Using Two or More Conversion Factors

The average speed of a nitrogen molecule in air at 25°C is 515 m/s. Convert this speed to miles per hour.

Solution On the back inside cover of the book, we find that 1 mi = 1.6093 km1 km = 103 m60 s = 1 min 60 min = 1 hr

Page 163: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.11 Converting Volume Units

Earth’s oceans contain approximately 1.36 × 109 km3 of water. Calculate the volume in liters.

Page 164: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.11 Converting Volume Units

Earth’s oceans contain approximately 1.36 × 109 km3 of water. Calculate the volume in liters.

Solution1 L = 10–3 m3

1 km = 103 m

Page 165: Chapter 1 Lecture- Matter & Measurement

SAMPLE EXERCISE 1.11 Converting Volume Units

Earth’s oceans contain approximately 1.36 × 109 km3 of water. Calculate the volume in liters.

Solution1 L = 10–3 m3

1 km = 103 m

Thus, converting from km3 to m3 to L, we have