chapter 1 matter. 1-1 scientific method: a systematic approach to solving problems. does not...

Chapter 1

Matter

1-1 Scientific Method:

A systematic approach to solving problems.• Does not guarantee scientific success• Many discoveries made by accident

1-2 Properties of Matter:

• Matter: Anything that has mass and takes up space.

• Physical Properties:□Can be observed without changing a

substance into another substance.• Color, Boiling point, density, mass, volume,

etc.

• Chemical Properties:□Can only be observed when a substance

is changed into another substance.• Flammability, corrosiveness, reactivity with

acid, etc.

• Intensive Properties:□ Independent of the amount of the

substance that is present.• Density, boiling point, color, etc.

• Extensive Properties:□Dependent upon the amount of the

substance present.• Mass, volume, energy, etc.

Changes of Matter• Physical Changes:

□Changes in matter that do not change the composition of a substance.• Changes of state, temperature, volume, etc.

• Chemical Changes (Reactions):□Changes that result in new substances.

• Combustion, oxidation, decomposition, etc.

• Atoms are the building blocks of matter.• Each element is made of the same kind of

atom.• A compound is made of two or more different

kinds of elements.

1-3 Classification of Matter

• Molecules are the smallest units of compounds.

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• Substance (pure): Composition and properties are uniform in every sample– elements and compounds

• Mixture: Composition varies from sample to sample

• Homogeneous Mixture: uniform composition – AKA solutions (air, salt water, gasoline)

• Heterogeneous Mixture: components separate into regions– Italian dressing, sand and water

Separating Mixtures

• Mixtures can be separated into components by physical means

Distillation:

Separates homogeneous mixture on the basis of differences in boiling point.

Chromatography:Separates substances based on differing abilities of compounds to adhere to the surface of a solid

Filtration:

Separates solid substances from liquids and solutions.

States of Matter

Inks and food coloring are typically composed of many different dyes which can be separated by paper chromatography. Which of the following terms apply to inks?

1. substance

2. homogenous

3. compound

4. element

5. heterogeneous

Inks and food coloring are typically composed of many different dyes which can be separated by paper chromatography. Which of the following terms apply to inks?

1. substance

2. homogenous

3. compound

4. element

5. heterogeneous

Which of the following separations cannot be achieved using a physical process and, therefore, requires a chemical process?

1. salt from sea water

2. water from honey

3. hydrogen from water

4. ice from water

5. fish from water

Which of the following separations cannot be achieved using a physical process and, therefore, requires a chemical process?

1. salt from sea water

2. water from honey

3. hydrogen from water

4. ice from water

5. fish from water

1-4 Measurement of Matter

SI Units

• Système International d’Unités

Metric System

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

What is the name given to the unit that equals: A. 10–9 gram B. 10–6 secondC. 10–3 meter

SI Unites

• Mass: quantity of matter in an object– Grams (g)

• Time: seconds (s)• Volume: liter (L) and the milliliter (mL)

– 1 mL = 1 cm3

10.0 cm

10.0 cm

10.0 cm

The volume of the cube to the right is

1. 1.00 L

2. 100 mL

3. 1.00 kL

4. 30 cm3

5. 1.00 dL

10.0 cm

10.0 cm

10.0 cm

The volume of the cube to the right is

1. 1.00 L

2. 100 mL

3. 1.00 kL

4. 30 cm3

5. 1.00 dL

Temperature:

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

• Celsius and Kelvin scales are most often used.

• The Celsius scale is based on the properties of water.o 0C is the freezing point of water.o 100C is the boiling point of water.

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• F = 9/5(C) + 32• C = 5/9(F − 32)

1-5 Density and % Comp

d= mV

• Example Problems

% Comp=Part

TotalX 100

1-6 Uncertainties in Measurements

• Systematic errors (built in errors)– Thermometer constantly 2°C too low.

• Random errors– Limitation in reading a scale.

• Precision– Reproducibility of a measurement.

• Accuracy– How close to the real value.

General Chemistry: Chapter 1

Precision

Reproducibility ∼ 0.1 g ∼ 0.0001 g

Precision low high

1-7 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.

Significant Figures1. 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.

Pacific/Atlantic Trick

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.

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

Dimensional Analysis

hr

s

ft

mi

m

ft

s

m 515

First consider the units that need to be converted

Now find equalities between the units

1 m = 3.28 ft1 mi = 5280 ft1 hr = 3600 s

Now substitute the numbers

hr 1

s 3600

ft 5280

mi 1

m 1

ft 3.28

s

m 515

Ans 1151.73 mi/hr

What is the mass in lbs of 1.00 gal of water? The density of water is 1.00 g/mL.

g

lb

mL

g

L

mL

gal

Lgal 1.00

1.0 gal = 3.79 L1 L = 1000mL1 lb = 454 g

454g

1lb

mL 1

g 1

L 1

1000mL

gal 1

L 3.79gal 1.00

8.33lbs

Blood plasma for adults is about 3.1 L. Its density is 1.020 g/cm3. How many pounds of blood plasma are there in your body? ( 1 lb = 453.6 g)

3

3

g 1000 kg 1 cm kg1. 0.90 = 0.90

cm 1 g 1000 L L

The average density of a human brain is 0.90 g cm-3. Which of the following is the correct process to convert g cm-3 to kg L-1?

3-3

3

g 1 kg 10 cm kg2. 0.90 = 9.0 10

cm 1000 g 1 L L

3

3

g 1 kg 1000 cm kg3. 0.90 = 0.90

cm 1000 g 1 L L

3

3

g 1000 kg 1 cm kg1. 0.90 = 0.90

cm 1 g 1000 L L

The average density of a human brain is 0.90 g cm-3. Which of the following is the correct process to convert g cm-3 to kg L-1?

3-3

3

g 1 kg 10 cm kg2. 0.90 = 9.0 10

cm 1000 g 1 L L

3. 0.90

g

cm3

1 kg

1000 g

1000 cm3

1 L = 0.90

kg

L

The density of the earth is about 4 g ml-1. Which of the following is the correct process to convert g ml-1 to kg m-3?

36 3 3

g 1000 kg 1 ml kg3. 4 = 4 10

ml 1 g 1 10 m m

3 3

g 1 kg 1000 ml kg2. 4 = 4

ml 1000 g 1 m m

63

3 3

g 1 kg 1 10 ml kg1. 4 = 4 10

ml 1000 g 1 m m

From NASA files

The density of the earth is about 4 g ml-1. Which of the following is the correct process to convert g ml-1 to kg m-3?

36 3 3

g 1000 kg 1 ml kg3. 4 = 4 10

ml 1 g 1 10 m m

3 3

g 1 kg 1000 ml kg2. 4 = 4

ml 1000 g 1 m m

63

3 3

g 1 kg 1 10 ml kg1. 4 = 4 10

ml 1000 g 1 m m

From NASA files

A Galileo thermometer functions based on the dependence of density on temperature. Which of the following statements is correct?

1. The red ball at the bottom is less dense than the black ball on top.

2. The red ball is less dense than the liquid in the cylinder.

3. The black ball at the top is more dense than the blue ball on the bottom.

4. The black ball at the top is less dense than the liquid in the cylinder.

red

black

Which of the following expresses the result of the following calculation with the correct number of significant figures?

1. 9.027 x 102 cm

2. 9.0269 x 102 cm3

3. 9.027 x 102 cm3

4. 9.026 x 102 cm3

5. 9.0 x 102 cm3

31.621 cm x 10.22 cm x 2.793292 cm =

Which of the following expresses the result of the following calculation with the correct number of significant figures?

1. 9.027 x 102 cm

2. 9.0269 x 102 cm3

3. 9.027 x 102 cm3

4. 9.026 x 102 cm3

5. 9.0 x 102 cm3

31.621 cm x 10.22 cm x 2.793292 cm =

Which of the following expresses the result of the following calculation with the correct number of significant figures and appropriate units?

86.31246762 g cm-3 x 10.5 cm3 =

1. 906.3 g

2. 906.28091 g cm3

3. 906.2 g cm-6

4. 906.28 g

5. 906 g

Which of the following expresses the result of the following calculation with the correct number of significant figures and appropriate units?

86.31246762 g cm-3 x 10.5 cm3 =

1. 906.3 g

2. 906.28091 g cm3

3. 906.2 g cm-6

4. 906.28 g

5. 906 g

Which of the following do you think would be the best unit of measure to express the height of the Eiffel tower.

1. centimeters

2. nanometers

3. gigameters

4. meters

5. kilometers

Which of the following do you think would be the best unit of measure to express the height of the Eiffel tower.

1. centimeters

2. nanometers

3. gigameters

4. meters

5. kilometers

Which of the following is an SI unit ?

2. ml

3. kg

4. mg

1. km

5. cm

Which of the following is an SI unit ?

2. ml

3. kg

4. mg

1. km

5. cm