Chemistry

Protons

A stable subatomic particle in the atomic nuclei w/ a positive charge equal in magnitude to that of an electron but of opposite sign

Neutrons

A subatomic particle of about the same mass as a proton but w/out an electrical charge

Electrons

Negatively charged subatomic particle that is 1/1836 times smaller than a proton

In a neutrally charged atom, what and what are equal?

electrons and protons

Atomic # = ?

Number of protons in an element

How to find the number of neutrons

neutrons = mass # - atomic #

What is the mass of both protons and neutrons?

1.67×10²⁴ or 1 amu

Isotopes

The same chemical element but with different #s of neutrons. Same element but w/ different weights

Ions

An atom or group of atoms w/ a net electrical charge.

• atoms becomes an ion if it gains or loses electrons

Cation

Positively charged atom

• “Cation are ‘paw’sitively charged”

What happens if an atom loses an electron

it becomes a cation

Anion

negatively charged atom

What happens when an atom gains an electron?

it becomes an anion

Shell

electrons revolve around the nucleus in a specific circular path knwon as an orbit or shell

Subshell

A division of electron shells separated by electron orbital

Ionic bonds

Complete transfer of valence electron(s) between atoms

Octet rule

Atoms prefer to have 8 electrons in their valence shell. They may lose, gain, or share electrons

Covalent bonds

Sharing of electron pairs between atoms

What is the number of electrons needed for covalent bonds

2

Which elements are covalent bonds typical to?

CHON: Carbon, Oxygen, Hydrogen, Nitrogen

Covalent bonds typically form between what and what?

A metal and nonmetal

Period indicates what?

how many electron shells an element has

Groups indicates what?

Indicates the # of valence electrons the element in the group has, though it doesn’t apply to transition metals

Matter

Anything that has weight and occupies space/volume. Can be solid, liquid, or gas

Mass

The amount of matter an object contains

Volume

The amount of space an object occupies

• Typically measured in literes or milliliters

Density

The relationship between te mass and volume of an object

How do you calculate the density of an object?

D = Mass/volume

Density is inversely or directly proportional to mass

directly

Density is directly or inversely proportional to volume

Inversely

Melting

When a solid gains heat and changes into a liquid

Freezing

Process where. aliquid loses heat and turns into solid

Condensation

Process where a gas loses heat and turns into a liquid

Evaporation

Transformation of a liquid into a gas

Sublimation

Process where a solid changes directly into a gas w/out first becoming a liquid

Deposition

Also known as desublimation. When a gas changes directly into a solid w/out first becoming a liquid

Chemical reaction

One or more substances, known as reactants, are transformed into different substances called products

Reactants

Substances that present at the start of a chemical reaction that participates in the reaction

products

Substances that are formed as a result of a chemical reaction

Combination

Two or more substances combine to form a single product

• EX: A + B → AB

Decomposition

A single substance breaks down into two or more substances

• EX: AB → A+B

Single Displacement

One or more element in a compound is replaced by another element

• EX: A + BC → B + AC

Double displacement

Elements in two different compounds swap places w/ each other to form new compounds

• EX: AB + BC → AD + BC

• The inner elements combine and the oter elements combine to form new compounds

Combustion

A substance (usually. a hydrocarbon) reacts w/ oxygen to produce heat, light, and typically produces carbon dioxide and water

• Hallmark sign of combustion: The second reactant is oxygen and the products are carbon dioxide and water

Moles

Units of measurements that is the amount of pure substances containing teh same # of chemical units

Avogadro’s number

6.022 × 10²³

Collision theory

for particles to react, they have to collide w/ each other w/ sufficient energy (activation energy)

Catalyst

Higher rate of reaction w/ less energy

• Speed up a reaction w/out being used up in the reactions themselves

Exothermic reactions

energy/heat is released at the reaction

What type of reactions are exothermic reactions?

Combustion, oxidation, neutralization

Endothermic reactions

takes in heat energy from teh surroundings. Absorb heat

Equilibrium

When the rate of the forward reaction equals the rate of the reverse reactions in a closed system

• Reactant 1 + reactant 2 → product

• product → reactant 1 + reactant 2

Static equilibrium

the forward and reverse reaction are occuring at the same time

• Continuously happening

Adhesion

binding or attraction between dissimilar molecules, atoms, surfaces, and substances

Cohesion

Attraction of molecules for other molecules of the same kind

Is water polar or non-polar?

Polar

Solution

A homogenous mixture of one or more solutes dissolved in a solvent

Homogenous mixture

When the solute is completely dissolved in the solvent. Not easily separated

heterogenous mixture

The solute and solvents are still easily separated such as pebbles in water

Solutes

A substance that can be dissolved into a solution by a solvent and is present in smaller amounts

Solvent

A substance with the ability to dissolve other substances to form a solution and is present in larger amounts

Polar substances

soluble in water

Non-polar substances

not soluble in water

Molarity

# of solutes per one liter of solution

• M = moles/liter

Dilution

process of reducing the concentration of a solute in. asolution by adding more solvent

Hypertonic

has a higher solute concentration. Solutes flow out

Hypotonic

Has a lower solute concentration. Solutes flow in

Isotonic

contains the same concentration of water and solutes

• No osmotic flow

Osmosis

Diffusion of solvent molecules (water) through selectively permeable membrane from. aregion of high water potential to a region of lower water potential

Acid

substances that increase concentration of hydrogen ions (H+)

Base

Substances that decrease concentration of hydrogen ions (H+)

Wide range indicator

chemical compound that changes color based on pH

In a wide range indicator, what color corresponds with acidic

red

In a wide range indicator, what color corresponds with alkaline

blue

Universal indicator

color range from deep red in very acidic to blue/purple to very alkaline

what color does blue litmus paper indicate

alkaline

What color does red litmus apper indicate

acidic

pH probe

gives more accurate readings of pH

What happens when acids and bases are mixed

They undergo neutralization

• Typically results in salt or water