Chemistry CH1 by Owen Borville October 6, 2025
Chemistry is the study of matter and the changes associated with matter. Matter is anything that has mass and occupies space. Scientists including chemists use the scientific method in their work.
The steps of the scientific method are to (1) Observe and ask a Question, (2) Conduct Research, (3) formulate a Hypothesis, (4) Test the Hypothesis with an Experiment, (5) Analyze the Data, and finally (6) Communicate the results and draw a (7) Conclusion. Scientists may revisit or adjust steps.
Quantitative properties are properties that can be measured. Measured quantities must include units. The English system of units uses feet, gallons, pounds, etc. The metric system of measurement includes units such as the meter, liter, kilogram, etc.
The International System of Units (SI Units) was designed for all scientists. The seven SI base units are: Length (meter, m), Mass (kilogram, kg), Time (second, s), Electric Current (ampere, A), Temperature (kelvin, K), Amount of Substance (mole, mol), Luminous Intensity (candela, cd).
The Magnitude of Units and their Prefixes:
Tera= T (1x10^12= 12 zeros) (1,000,000,000,000)
Giga= G (1x10^9= 9 zeros) (1,000,000,000)
Mega= M (1x10^6= 6 zeros) (1,000,000)
Kilo= k (1x10^3= 3 zeros) (1,000)
Deci= d (1x10^-1= 1 decimal space) (0.1)
Centi= c (1x10^-2= 2 decimal spaces)(0.01)
Milli= m (1x10^-3)= 3 decimal spaces)(0.001)
Micro= µ (1x10^-6)=6 decimal spaces)(0.000001)
Nano= n (1x10^-9)=9 decimal spaces)(0.000000001)
Pico= p (1x10^-12)=12 decimal spaces)(0.000000000001)
Chemistry is the study of matter and the changes associated with matter. Matter is anything that has mass and occupies space. Scientists including chemists use the scientific method in their work.
The steps of the scientific method are to (1) Observe and ask a Question, (2) Conduct Research, (3) formulate a Hypothesis, (4) Test the Hypothesis with an Experiment, (5) Analyze the Data, and finally (6) Communicate the results and draw a (7) Conclusion. Scientists may revisit or adjust steps.
Quantitative properties are properties that can be measured. Measured quantities must include units. The English system of units uses feet, gallons, pounds, etc. The metric system of measurement includes units such as the meter, liter, kilogram, etc.
The International System of Units (SI Units) was designed for all scientists. The seven SI base units are: Length (meter, m), Mass (kilogram, kg), Time (second, s), Electric Current (ampere, A), Temperature (kelvin, K), Amount of Substance (mole, mol), Luminous Intensity (candela, cd).
The Magnitude of Units and their Prefixes:
Tera= T (1x10^12= 12 zeros) (1,000,000,000,000)
Giga= G (1x10^9= 9 zeros) (1,000,000,000)
Mega= M (1x10^6= 6 zeros) (1,000,000)
Kilo= k (1x10^3= 3 zeros) (1,000)
Deci= d (1x10^-1= 1 decimal space) (0.1)
Centi= c (1x10^-2= 2 decimal spaces)(0.01)
Milli= m (1x10^-3)= 3 decimal spaces)(0.001)
Micro= µ (1x10^-6)=6 decimal spaces)(0.000001)
Nano= n (1x10^-9)=9 decimal spaces)(0.000000001)
Pico= p (1x10^-12)=12 decimal spaces)(0.000000000001)
Mass is a measure of the amount of matter in an object or sample. The weight of an object can change depending on the location on Earth, but the mass does not change and mass always stays the same. Mass is measured in kilograms or grams in the SI system. 1 kg = 1000 g.
Atomic Mass Unit is used to express the masses of atoms and other similar sized objects. One atomic mass unit = 1 amu = 1.66o5378 x 10^24 grams
Temperature Scales Used in Chemistry:
The Celsius scale (degrees Celsius) (°C) = the freezing point of pure water = 0°C, boiling point of pure water = 100 °C
The Kelvin scale (K) = the absolute scale and the lowest possible temperature = 0 K (absolute zero)
Conversion equation from Kelvin to Celsius scale = K = °C + 273.15
Fahrenheit scale (degrees Fahrenheit) (°F) = the freezing point of pure water = 32 °F, boiling point of pure water = 212 °F
Celsius to Fahrenheit conversion equations = (°F) = (°C) x (9/5) + 32
(°C) = (°F - 32) x (5/9)
Therefore, a temperature of 80 (°F) = 26.67 (°C). A temperature of 10 (°C) = 50 (°F)
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Derived Units are units of measurement that are not included in the base SI units. The derived SI unit for volume is the meter cubed or cubic meter (m^3). Another unit for volume is the liter (L).
One decimeter cubed equals one liter. 1 dm ^3 = 1 L
One centimeter cubed equals one milliliter. 1 cm^3 = 1 mL
Atomic Mass Unit is used to express the masses of atoms and other similar sized objects. One atomic mass unit = 1 amu = 1.66o5378 x 10^24 grams
Temperature Scales Used in Chemistry:
The Celsius scale (degrees Celsius) (°C) = the freezing point of pure water = 0°C, boiling point of pure water = 100 °C
The Kelvin scale (K) = the absolute scale and the lowest possible temperature = 0 K (absolute zero)
Conversion equation from Kelvin to Celsius scale = K = °C + 273.15
Fahrenheit scale (degrees Fahrenheit) (°F) = the freezing point of pure water = 32 °F, boiling point of pure water = 212 °F
Celsius to Fahrenheit conversion equations = (°F) = (°C) x (9/5) + 32
(°C) = (°F - 32) x (5/9)
Therefore, a temperature of 80 (°F) = 26.67 (°C). A temperature of 10 (°C) = 50 (°F)
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Derived Units are units of measurement that are not included in the base SI units. The derived SI unit for volume is the meter cubed or cubic meter (m^3). Another unit for volume is the liter (L).
One decimeter cubed equals one liter. 1 dm ^3 = 1 L
One centimeter cubed equals one milliliter. 1 cm^3 = 1 mL
Density: The density of a substance is equal to the mass of the substance divided by the volume.
density = (mass)/(volume) = d= m/v
Units of density for solids = g/cm^3 (grans per cubic centimeter)
Units of density for liquids = g/mL (grams per milliliter)
Units of density for gases = g/L (grams per liter)
Measurements by any method other than counting whole numbers must be rounded to the nearest significant figures.
Significant figures are the meaningful digits in a reported number of measurement. The last digit in a measurement is the uncertain digit. The rules for counting significant figures in a measurement are:
(1) Any nonzero digit is significant. Ex. 125.3 = 4 significant figures
(2) Zeros between nonzero digits are significant. Ex. 208 = 3 significant figures; 7007.05 = 6 significant figures
(3) Zeros to the left of the first nonzero digit are not significant. Ex. 0.0012 = 2 significant figures; 0.0005 = 1 significant figure
(4) Zeros to the right of the last nonzero digit are significant if a decimal is present. Ex. 9.3000 = 5 significant figures
(5) Zeros to the right of the last nonzero digit in a number that does not contain a decimal point may or may not be significant. To avoid confusion, use scientific notation in this case. Ex. 200 = 2 x 10^2 = 1 significant figure; 2.0 x 10^2 = 2 significant figures; Ex. 7.00 x 10^-5 = 0.0000700 = 3 significant figures.
When adding or subtracting numbers, the answer cannot have more digits to the right of the decimal point than any of the original numbers. If adding a number with two digits right of the decimal point to a number with three digits right of the the decimal point, the answer must be rounded to two digits after the decimal point.
When multiplying or dividing numbers, the number of significant digits in the final answer should be the original number of the smallest number of significant figures. In other words, when multiplying a number with two significant digits with a number with four significant digits, the final answer can only have two significant digits and must be rounded accordingly.
When calculating two numbers, one of which is a counted whole number and the other a decimal, the counted whole number does not limit the significant figures of the final answer. Ex. 5 x 3.5 = 17.5.
In calculations with multiple steps, round at the end of the calculation to reduce any rounding errors. Ex. 4.29 x 8.76 = 37.5804. Final step. 37.5804 x 5.42 = 204.
Accuracy and Precision in Measurement: Accuracy is how close a measurement is to the true value. Precision is how close a series of multiple measurements are to each other. Therefore if a series of measurements are not close to the true value, but each measurement is close to each other, the measurements are precise but not accurate. The measurements can be accurate but not precise if all of the measurements are near the true value but are scattered in different positions or values. Accurate and precise measurements will all be near the true value and all near the same position or value. Neither accurate or precise measurements will not be near the true value and each measurement will be in different positions or measured values.
A conversion factor is a fraction in the same quantity is expressed one way in the numerator and another way in the denominator. Ex. If one meter is equal to 3.3 feet, then the conversion factor can be either (1 m/3.3 ft) or (3.3 ft/1 m). This conversion factor can be used to convert measurements from feet to meters or vice-versa.
Using dimensional analysis or the factor-label method, the units of original value must be in the denominator of the conversion factor in order to cancel out units. Ex. To convert 6.0 feet to meters, use the conversion factor where meters is in the denominator in order to cancel out units. Therefore, 6.0 ft multiplied by (1 m/3.3 ft), the feet cancel out and 6.0 is divided by 3.3 ft to obtain the answer = 1.8288=1.8 meters (round to 2 significant figures).
Classification of Matter:
A substance is a form of matter that has a definite composition and distinct properties. Substances can be a compound or a single chemical element. Substances are distinguished from each other by composition and may have unique appearance, smell, taste, or other properties. Ex. gold, silver, oxygen, iron, water (H20), carbon dioxide (CO2), silica or silicon dioxide (SiO2), hydrogen (H2), carbon monoxide (CO).
A mixture is a physical combination of two or more substances. A homogeneous mixture is uniform throughout the mixture (also called a solution). Ex. saltwater, air, vinegar, steel, bronze, coffee. A heterogeneous mixture is not uniform throughout the mixture and the different parts are visible, while the composition of each sample will vary. Ex. oil and water, cereal in milk, sand and water, soil, concrete.
Solid forms of matter contain particles that are held tightly in an ordered pattern. Solid matter does not conform to the shape of its container. Liquid forms of matter are made of particles that are close together but are not held tightly in position. Liquid particles also conform to the shape of their container. Gas forms of matter have particles that have have large separation between each particle and the particles move freely to fit its container. Gas particles conform to both the shape and volume of its container.
All substances can exist as a solid, liquid, or a gas state. The state of the substance can be converted or changed without changing the identity of the substance.
A mixture can be separated by physical means into its components without changing the identities of the components.
Quantitative properties of matter can be measured and expressed with a number. Qualitative properties do not require measurement and are usually based on observation.
A physical property is one that can be observed and measured without changing the identity of the substance. Ex. color, odor, density, melting point, boiling point, electrical conductivity, hardness, solubility, and the state of matter of solid, liquid, or gas.
A physical change is one in which the state of matter changes, but the identity of the matter does not change, such as during changes of state of matter. (Ex. melting, freezing, boiling, condensation). In addition, cutting or crushing a substance, or dissolving a substance in water are physical changes. When mixtures are separated, the identity of the matter does not change.
A chemical property is a property of a substance when it interacts with another substance. Ex. flammability, toxicity, corrosiveness (rust), reactivity, and radioactivity.
A chemical change is one that results in a change in composition of a substance and the original substances no longer exist. Ex. oxidation, burning a substance, rusting or corrosion of iron, apple browning, cooking eggs, milk souring, and food digestion in the body.
Extensive properties of matter depend on the amount of matter, such as mass and volume. Intensive properties of matter do not depend on the amount of matter, such as temperature and density.
A constant in chemistry is a quantity that does not change under specific conditions, such a universal physical constants on Earth or control variables in experiments.
density = (mass)/(volume) = d= m/v
Units of density for solids = g/cm^3 (grans per cubic centimeter)
Units of density for liquids = g/mL (grams per milliliter)
Units of density for gases = g/L (grams per liter)
Measurements by any method other than counting whole numbers must be rounded to the nearest significant figures.
Significant figures are the meaningful digits in a reported number of measurement. The last digit in a measurement is the uncertain digit. The rules for counting significant figures in a measurement are:
(1) Any nonzero digit is significant. Ex. 125.3 = 4 significant figures
(2) Zeros between nonzero digits are significant. Ex. 208 = 3 significant figures; 7007.05 = 6 significant figures
(3) Zeros to the left of the first nonzero digit are not significant. Ex. 0.0012 = 2 significant figures; 0.0005 = 1 significant figure
(4) Zeros to the right of the last nonzero digit are significant if a decimal is present. Ex. 9.3000 = 5 significant figures
(5) Zeros to the right of the last nonzero digit in a number that does not contain a decimal point may or may not be significant. To avoid confusion, use scientific notation in this case. Ex. 200 = 2 x 10^2 = 1 significant figure; 2.0 x 10^2 = 2 significant figures; Ex. 7.00 x 10^-5 = 0.0000700 = 3 significant figures.
When adding or subtracting numbers, the answer cannot have more digits to the right of the decimal point than any of the original numbers. If adding a number with two digits right of the decimal point to a number with three digits right of the the decimal point, the answer must be rounded to two digits after the decimal point.
When multiplying or dividing numbers, the number of significant digits in the final answer should be the original number of the smallest number of significant figures. In other words, when multiplying a number with two significant digits with a number with four significant digits, the final answer can only have two significant digits and must be rounded accordingly.
When calculating two numbers, one of which is a counted whole number and the other a decimal, the counted whole number does not limit the significant figures of the final answer. Ex. 5 x 3.5 = 17.5.
In calculations with multiple steps, round at the end of the calculation to reduce any rounding errors. Ex. 4.29 x 8.76 = 37.5804. Final step. 37.5804 x 5.42 = 204.
Accuracy and Precision in Measurement: Accuracy is how close a measurement is to the true value. Precision is how close a series of multiple measurements are to each other. Therefore if a series of measurements are not close to the true value, but each measurement is close to each other, the measurements are precise but not accurate. The measurements can be accurate but not precise if all of the measurements are near the true value but are scattered in different positions or values. Accurate and precise measurements will all be near the true value and all near the same position or value. Neither accurate or precise measurements will not be near the true value and each measurement will be in different positions or measured values.
A conversion factor is a fraction in the same quantity is expressed one way in the numerator and another way in the denominator. Ex. If one meter is equal to 3.3 feet, then the conversion factor can be either (1 m/3.3 ft) or (3.3 ft/1 m). This conversion factor can be used to convert measurements from feet to meters or vice-versa.
Using dimensional analysis or the factor-label method, the units of original value must be in the denominator of the conversion factor in order to cancel out units. Ex. To convert 6.0 feet to meters, use the conversion factor where meters is in the denominator in order to cancel out units. Therefore, 6.0 ft multiplied by (1 m/3.3 ft), the feet cancel out and 6.0 is divided by 3.3 ft to obtain the answer = 1.8288=1.8 meters (round to 2 significant figures).
Classification of Matter:
A substance is a form of matter that has a definite composition and distinct properties. Substances can be a compound or a single chemical element. Substances are distinguished from each other by composition and may have unique appearance, smell, taste, or other properties. Ex. gold, silver, oxygen, iron, water (H20), carbon dioxide (CO2), silica or silicon dioxide (SiO2), hydrogen (H2), carbon monoxide (CO).
A mixture is a physical combination of two or more substances. A homogeneous mixture is uniform throughout the mixture (also called a solution). Ex. saltwater, air, vinegar, steel, bronze, coffee. A heterogeneous mixture is not uniform throughout the mixture and the different parts are visible, while the composition of each sample will vary. Ex. oil and water, cereal in milk, sand and water, soil, concrete.
Solid forms of matter contain particles that are held tightly in an ordered pattern. Solid matter does not conform to the shape of its container. Liquid forms of matter are made of particles that are close together but are not held tightly in position. Liquid particles also conform to the shape of their container. Gas forms of matter have particles that have have large separation between each particle and the particles move freely to fit its container. Gas particles conform to both the shape and volume of its container.
All substances can exist as a solid, liquid, or a gas state. The state of the substance can be converted or changed without changing the identity of the substance.
A mixture can be separated by physical means into its components without changing the identities of the components.
Quantitative properties of matter can be measured and expressed with a number. Qualitative properties do not require measurement and are usually based on observation.
A physical property is one that can be observed and measured without changing the identity of the substance. Ex. color, odor, density, melting point, boiling point, electrical conductivity, hardness, solubility, and the state of matter of solid, liquid, or gas.
A physical change is one in which the state of matter changes, but the identity of the matter does not change, such as during changes of state of matter. (Ex. melting, freezing, boiling, condensation). In addition, cutting or crushing a substance, or dissolving a substance in water are physical changes. When mixtures are separated, the identity of the matter does not change.
A chemical property is a property of a substance when it interacts with another substance. Ex. flammability, toxicity, corrosiveness (rust), reactivity, and radioactivity.
A chemical change is one that results in a change in composition of a substance and the original substances no longer exist. Ex. oxidation, burning a substance, rusting or corrosion of iron, apple browning, cooking eggs, milk souring, and food digestion in the body.
Extensive properties of matter depend on the amount of matter, such as mass and volume. Intensive properties of matter do not depend on the amount of matter, such as temperature and density.
A constant in chemistry is a quantity that does not change under specific conditions, such a universal physical constants on Earth or control variables in experiments.