Comprehensive Chemistry: Matter, Properties, and Measurement

Matter

Matter is what makes up all substances.

Molecule

A molecule is a small, definite group of atoms and subatomic particles bonded together.

Major properties of matter

Matter takes up space, has mass, and attracts other matter with gravity.

Mass

Mass is a very fundamental property that can only be defined indirectly.

Chemical properties

Chemical properties are characteristics that can be observed only when they react with another substance.

Example of chemical property

Hydrogen combines explosively with oxygen (H2O), rust (corrosiveness), flammability, evolution of a gas, change of color.

Physical properties

Physical properties are characteristics that can be observed without changing into another substance.

Example of physical property

Density, hardness, color, melting point.

Density formula

d = m (grams) / v (mL), m = d * v, v = m / d.

Intensive property

An intensive property is a characteristic that is independent of the amount of substance present.

Examples of intensive properties

Color, boiling point, melting point, conductivity, hardness, specific gravity, ductility.

Extensive property

An extensive property is a characteristic that varies with the quantity of the substances present.

Examples of extensive properties

Length, width, mass, weight, volume, energy, enthalpy, entropy.

States of matter

Solids have definite shapes and volumes, liquids occupy definite volumes but do not have definite shapes, gases have neither a definite shape nor volume.

Boiling point (nbp)

The temperature at which a substance transitions from a liquid to a gas.

Critical point (C)

The point beyond which a substance undergoes a significant transition.

Melting point (mp)

The temperature at which a substance transitions from solid to liquid.

Sublimation point (sp)

The temperature at which a substance transitions directly from solid to gas.

Measurement importance

All quantities of measurements have a unit.

Unit of length

Meter (m).

Unit of mass

Kilogram (kg).

Unit of time

Second (s).

Unit of temperature

Kelvin (K).

Unit of amount

Mole (mol).

Unit of area

Square meter (m²).

Unit of volume

Cubic meter (m³).

Unit of force

Newton (N).

Unit of pressure

Pascal (Pa).

Unit of energy

Joule (J).

Unit of power

Watt (W).

Accuracy

how close the measurements is to the actual value

Precision

how well can the measurement be repeated

Significant Figures

the digits in a number that carry meaningful information about its precision

Exact Numbers

do not limit the # of sig figs, such as counting numbers or exact conversions

Unit Conversion Factor

a fraction in which the numerator is a quantity equal or equivalent to the quantity to the denominator, but expressed in different units

1°C= 1K = 1.8°F

a conversion relationship between Celsius, Kelvin, and Fahrenheit

°K = °C + 273.15

the formula to convert Celsius to Kelvin

°F - 32 = 1.8 °C

the formula to convert Fahrenheit to Celsius

Pure Substance

one type of matter, which can be an element or a compound

Element

the simplest kind of material with unique physical and chemical properties

Compound

a substance that consists of two or more elements linked together in definite proportions

Homogeneous Mixtures

the constituents are distributed uniformly throughout the sample

Heterogeneous Mixtures

the individual components can be seen as separate domains

Filtration

a method to separate mixtures without chemical reactions, such as separating ramen from water

Distillation

a method of separating mixtures by heating and cooling

Chemical Reaction

the transformation of one or more substances into different substances

Atomic Theory

the theory that atoms are tiny nuclei (protons and neutrons) with a field of electrons floating around

Trailing Zeros with Decimal Point

counted as significant figures

Leading Zeros

not counted as significant figures

Trailing Zeros without Decimal Point

not counted as significant figures

Multiplication/Division with Sig Figs

the number with the fewest sig figs determines the number of sig figs in the answer

Addition/Subtraction with Sig Figs

the last decimal places of the numbers determines the place of the last sig fig in the answer

Atoms

The fundamental structural blocks of substances.

Protons

Positively charged particles inside the nucleus that may transform to neutrons.

Ions

Atoms that can lose or gain electrons.

Atomic Number

The number of protons in an atom, which uniquely identifies an element.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Neutron Number

Calculated as Mass# - Atomic#.

Electron Number

Calculated as Atomic# - Charge#.

Isotopes

Different types of atoms of the same element which have different number of neutrons.

Mass Spectrometer

An instrument that measures precisely masses and relative abundances of ions of atoms and molecules.

Avg Atomic Mass

Calculated using the formula: (mass)(% abundance) + (mass)(% abundance).

Compounds

Substances that have a fixed ratio of atoms held together by chemical bonds.

Law of Multiple Proportions

States that if two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other are in the ratio of small whole numbers.

Ionic Compound

Formed from metals and nonmetals where a positive ion transfers electrons to a negative ion.

Covalent Compound

Formed from nonmetals where atoms share electrons.

Metallic Bonds

Bonds formed between positive metal atoms held together by a sea of free-floating electrons.

Molecular Formula

Indicates the actual number of atoms in one molecule (e.g., C6H6).

Formula Unit

Indicates the lowest ratio of ions in an ionic compound (e.g., NaCl).

Empirical Formula

Indicates the simplest whole-number ratio of atoms (e.g., CH).

Ionic Crystals

The arrangement of ions in solids held together by ionic bonds.

Prefixes in Naming Compounds

Used to identify the quantity of atoms in covalent compounds.

Chemical Bonds

Forces that hold atoms together in compounds.

Fixed Ratio of Atoms

The specific proportion of different atoms in a compound that defines its composition.

Mono-

1

Di-

2

Tri-

3

Tetra-

4

Penta-

5

Hexa-

6

Hepta-

7

Octa-

8

Nona-

9

Deca-

10

Ionic Compounds

Compounds formed from metals and nonmetals.

Cation

The positively charged ion in an ionic compound.

Anion

The negatively charged ion in an ionic compound.

Binary Acids

Acids formed from hydrogen and one other nonmetal.

Oxoanion

A polyatomic ion that contains oxygen.

Oxoacids

Acids formed from oxyanions and hydrogen ions.

Mole

A macroscopic quantity representing 6.02 x 10^23 items.

Molar Mass

The mass in grams of one mole of a compound.

Formula Mass

The sum of the atomic masses of all atoms in a chemical formula.

Hydro-

Prefix indicating the presence of hydrogen in binary acids.

-ate

Suffix indicating a polyatomic ion with more oxygen.

-ite

Suffix indicating a polyatomic ion with less oxygen.

-ous acid

Ending for acids derived from -ite oxyanions.

-ic acid

Ending for acids derived from -ate oxyanions.

Onion

Suffix indicating a positive charge in polyatomic ions.

Hypo-

Prefix indicating even less oxygen in an oxyanion.