Chemistry Final Flashcards S1

Matter

Anything that has mass and takes up space (has volume). Matter is composed of tiny particles with empty space between them.

Pure Substance

Has a fixed composition.

Element

Made of only one type of atom (e.g., gold, Au). Cannot be broken down further by chemical means.

Compound

Made of two or more different elements chemically bonded together in a fixed ratio (e.g., water, H₂O). Can be broken down by chemical means.

Mixture

A combination of two or more substances that are not chemically bonded.

Homogeneous Mixture (Solution)

Looks uniform throughout (e.g., salt dissolved in water). Particles are evenly distributed.

Heterogeneous Mixture

Does not look uniform. You can see the different components (e.g., sand and water).

Atom

The smallest particle of an element.

Molecule

Two or more atoms bonded together. It can be a molecule of an element (e.g., O₂) or a molecule of a compound (e.g., H₂O).

Chemical Symbol

A one or two-letter abbreviation for an element (e.g., O for oxygen, H for hydrogen).

Chemical Formula

Uses chemical symbols and subscripts to show the number of each type of atom in a molecule (e.g., H₂O means 2 hydrogen atoms and 1 oxygen atom).

Particle Model

Explains the properties of solids, liquids, and gases based on the arrangement and movement of their particles.

Solid

Particles are tightly packed and vibrate in fixed positions. They have a definite shape and volume, high density, and are not compressible.

Liquid

Particles are close but can slide past one another. They have a definite volume but an indefinite shape, moderate density, and are not easily compressed.

Gas

Particles are far apart and move randomly and rapidly. They have an indefinite shape and volume, low density, and are highly compressible. They fill their container.

Melting

Solid to liquid.

Boiling/Vaporization

Liquid to gas.

Freezing

Liquid to solid.

Condensation

Gas to liquid.

Sublimation

Solid directly to gas.

Deposition

Gas directly to solid.

Physical Properties

Can be observed or measured without changing the substance's identity (e.g., color, density, melting point).

Physical Changes

Change the form or appearance of a substance but not its chemical composition (e.g., cutting paper, melting ice). Physical separation methods exploit these differences.

Chemical Properties

Describe a substance's ability to undergo a specific chemical change (e.g., flammability, reactivity with acid).

Chemical Changes

Result in a new substance with a different chemical composition.

Indicators of Chemical Change

Change in temperature (gets hot or cold), formation of a gas (bubbles, fizzing), formation of a precipitate (a solid forms in a liquid), change in color or odor.

Settling/Centrifuge

Separates a solid from a liquid based on density. A centrifuge spins the mixture to speed up the settling process.

Distillation

Separates liquids based on different boiling points. The substance with the lower boiling point boils first, turns into a gas, and is then condensed back into a liquid.

Filtration

Separates an insoluble solid from a liquid using a filter (e.g., coffee filter). The liquid passes through, and the solid is left behind.

Chromatography

Separates components of a mixture based on their different affinities for a stationary phase and a mobile phase.

Common Lab Equipment

Be able to identify and know the use of standard equipment like beakers (for holding liquids), graduated cylinders (for measuring liquid volume), scales (for measuring mass), and thermometers (for measuring temperature).

Reading Measurements

Read to one digit past the smallest marking on the device.

Graduated Cylinder Reading

Read at the bottom of the meniscus (the curved surface of the liquid).

Significant Figures (Sig Figs)

A way of indicating the precision of a measurement. When performing calculations, the final answer must be rounded to the correct number of significant figures based on the measurements used.

Scientific Notation

A way to express very large or very small numbers. The format is a×10^b, where 1≤a<10.

Precision

How close repeated measurements are to each other.

Accuracy

How close a measurement is to the true or accepted value.

Percent Error

measured value - actual value / actual value × 100%

Average Deviation

|m1- average| + |m2- average|… / Number of Measurements

Percent Deviation

average deviation / average × 100%

Basic SI Units - Mass

kilogram (kg)

Basic SI Units - Volume

liter (L) or cubic meter (m^3)

Basic SI Units - Density

g/mL or g/cm^3

Basic SI Units - Distance

meter (m)

Metric Prefix - Kilo

10^3

Metric Prefix - Hecto

10^2

Metric Prefix - Deka

10^1

Metric Prefix - Unit

10^0

Metric Prefix - Deci

10^-1

Metric Prefix - Centi

10^-2

Metric Prefix - Milli

10^-3

Temperature Conversion - Kelvin to Celsius

C = K - 273.15

Temperature Conversion - Celsius to Kelvin

K = C + 273.15

Dimensional Analysis (Fenceposting)

A method for converting between units using conversion factors. You arrange the units so that they cancel out, leaving the desired unit.

Example Fenceposting Problem

Convert 10.0 miles to kilometers, given 1 mile = 1.609 km. 10.0 miles × (1 mile / 1.609 km) = 16.09 km.

Particulate Nature of Matter

Matter is anything with mass that occupies space. It is made up of tiny spheres called atoms, with empty space between them.

States of Matter

The three main phases of matter are solid, liquid, and gas.

Phase Changes

A change from one phase to another is a physical change.

Boiling

Liquid to Gas

Counting Sig Figs with a decimal point

Count from the first nonzero digit on the left to the final digit on the right, including all zeros.

Counting Sig Figs without a decimal point

Count from the first nonzero digit to the last nonzero digit. Do not include any trailing zeros.

Addition/Subtraction with Sig Figs

The answer is rounded to the same decimal place as the number with the least precise digit.

Multiplication/Division with Sig Figs

The answer is rounded to have the same number of significant figures as the measurement with the fewest significant figures.

Basic SI Units

The textbook lists the basic units for mass (kg), volume (L), density (g/mL), and distance (m).

Metric Prefixes

Know the meaning of common prefixes like Kilo, Hecto, Deka, Deci, Centi, and Milli (KHDUDCM backbone).

Temperature Conversions

The textbook provides the conversion between Celsius and Kelvin: K = C + 273.15.

Mole

6.022×10²³ particles; counting unit for atoms/molecules/ions

Avogadro's Number

6.022×10²³

Atoms → Moles Conversion

Atoms ÷ 6.022×10²³ = moles

Moles → Atoms Conversion

Moles × 6.022×10²³ = atoms

Grams → Moles

Grams ÷ molar mass (g/mol)

Moles → Grams

Moles × molar mass (g/mol)

Conversion Backbone

Atoms ⇄ Moles ⇄ Grams (via Avogadro’s # and molar mass)

Molar Mass

Mass of 1 mole of a substance (g/mol)

Percent Composition

(Mass of element ÷ molar mass) × 100

Empirical Formula

Simplest whole-number ratio of atoms in a compound

Steps to Find Empirical Formula

% → grams → moles → divide by smallest → whole numbers

Molecular Formula

Actual atom ratio; whole-number multiple of empirical formula

Steps to Find Molecular Formula

Molar mass ÷ empirical mass = multiplier → multiply subscripts

Hydrate

Compound with water molecules attached (ex. CuSO₄·5H₂O)

Finding Formula of a Hydrate

Heat to remove water → find moles salt & water → divide to get ratio

Chemical Reaction

Process where reactants form new products

Reactants

Starting substances

Products

Substances produced

Coefficient

Large number in front of formula; indicates # of molecules

Subscript

Small number; indicates # of atoms in a molecule

Symbols in Equations

+, →, (s), (l), (g), (aq)

Law of Conservation of Mass

Matter isn't created/destroyed → equations must be balanced

Balancing Equations Steps

Write formula → count atoms → change coefficients → recheck

Word Equation → Chemical Equation

Translate words → write formulas → balance

Synthesis Reaction

A + B → AB

Decomposition Reaction

AB → A + B

Single Replacement Reaction

A + BC → AC + B

Double Replacement Reaction

AB + CD → AD + CB

Combustion Reaction

Hydrocarbon + O₂ → CO₂ + H₂O

Predicting Products

Identify reaction type + form correct ionic compounds

Diatomic Seven

Br₂, I₂, N₂, Cl₂, H₂, O₂, F₂

When to Write Diatomic Elements

When they are alone/uncombined in a reaction

Importance of Polyatomic Ions

Needed to write correct formulas and predict products

How are they arranged?

They are arranged around the nucleus by energy levels.