AP Chem Unit 1

Least precise

When adding or subtracting sig figs, answer must have no more sig figs than those in the measurement with the _______ number of sig figs

Least total

When multiplying or dividing sig figs, answer must have no more sig figs than those in the measurement with the _______ number of sig figs

Are not

Conversion factors, fundamental constants, and counted numbers are/are not considered when determining sig figs

Larger

The _______ the charges, the larger the energy of attraction

Smaller

The _______ the distance, the larger the energy of attraction

Proton

Positively charged subatomic particle with a mass of 1 amu

Neutron

Neutrally charged subatomic particle with a mass of 0 amu

Electron

Negatively charged subatomic particle with a mass of 1 amu

Isotopes

Atoms of the same element with different numbers of neutrons

Nuclide

Mass number is written above the symbol of the element and the atomic number is written before in this type of format used to describe isotopes

Average atomic mass

The weighted average mass of an element’s isotopes, the mass found on the periodic table

(Mass isotope 1 x % abundance)+(mass isotope 2 x % abundance)

Formula for weighted average

Mass spectrometry

Measures the masses of elements and their percent abundances

Filter paper

Separates a solid and liquid mixture by pouring the mixture through it, designed to only allow liquid to pass

Distillation

Separates a homogenous mixture of liquids by heating the mixture and the more volatile liquid is boiled off first

Paper chromatography

Separates a homogenous mixture by taking advantage of the fact that components will have different attractions to a solvent and a paper

Chemical formula

Shows the kinds of elements and numbers of atoms or moles of each element in the smallest representative unit of a substance

Molecule

The smallest representative unit for a covalent (nonmetal+nonmetal) compound

Formula unit

The smallest representative unit for an ionic (metal+nonmetal) compound

Formula mass

The sum of the average atomic masses of all the atoms represented in the formula of any formula unit or molecule

Molar mass

The mass of one mole of a pure substance, numerically equal to the formula mass but in grams per mole instead of AMU

Percent composition

The percent by mass of each element in a compound

Law of definite proportions

States that the molar ratio of elements in a specific compound is constant

(Element mass/compound mass)x100

Formula for mass percent of an element

Pressure

The force per unit area on a surface, defined by force/area

Barometers

Measure atmospheric pressure

760, 760, 101.3

1 ATM = _______ mmHg = _______ torr = _______ kPa

Temperature

The measure of the average kinetic energy of the particles in a sample of matter

1 atm, 0 Celsius

STP conditions

Lighter

Curves that are farther to the right and lower on a Maxwell-Boltzmann distribution are…

Kinetic-molecular theory

Based on the idea that particles of matter are always in motion

Large, far apart, empty space

Gases consist of _______ numbers of tiny particles that are _______ relative to their size. Most of the volume of a gas is…

Constant

Gas particles are in _______, rapid, random motion

No

Gas particles lose _______ energy when they collide with other particles or container walls

No

There are _______ forces of attraction and repulsion between gas particles

Temperature

The average kinetic energy of gas particles depends on…

Ideal gas

An imaginary gas that perfectly fits all the assumptions of the kinetic-molecular theory

Real gas

A gas that does not behave completely according to the assumptions of the kinetic-molecular theory

Polar

The more ________ the gas molecules, the greater the deviation from ideal behavior

Expand

Gases can _______ to completely fill their container

Compression

Forces particles that were very far apart closer together

Fluid

Gas particles are _______, or can easily slide past each other

Low

Gas particles have low/high density

Diffusion

Spontaneous mixing of the particles of two substances caused by their random motion

Effusion

A process by which gas particles pass through a tiny opening

PV=nRT

Ideal gas law

62.4

“R” for mmHg

62.4

“R” for torr

0.0821

“R” for atm

8.314

“R” for kPa

Liters, Kelvin, mol

The volume units, temperature units, and n units in the ideal gas law are…

22.4

At STP, 1 mol of gas takes up _______ L

Standard molar volume of gas

The volume occupied by one mole of a gas at STP

High, low

Gases behave most like gases at _______ temperatures and _______ pressure