chemistry final 2026

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chemical reaction

a process by which one or more substances are rearranged to form different substances; also called a chemical change

reactants

the starting substance in a chemical reaction

products

the substances formed during the reaction

balancing ensures that the number of atoms of each element is the same on both sides of the equation, thereby reflecting the law that the total mass of reactants equals the total mass of products

how does the law of conservation of mass relate to the balancing of chemical equations?

synthesis reaction

a chemical change in which two or more substances react to form a single new substance

decomposition reaction

a chemical change in which a single compound is broken down into two or more simple products

combustion reaction

a chemical change in which an element or a compound reacts with oxygen, often producing engird in the form of heat and light

single replacement reaction

a chemical change in which one element replaces a second element in a compound

double replacement reaction

a chemical change that involves an exchange of positive ions between two compounds.

synthesis general format

A+B → AB

decomposition general format

AB → A+B

Combustion general format

AX+O2 → AO+XO

single replacement general format

A+BX→AX+b or Y+BX→BY+X

double replacement general format

AX+BY→AY+BX

mole

the SI base unit used to measure the amount of a substance

6.02×10²³

how many atoms/ molecules/ formula units are found in a mole

avogadro’s number

what is the special name for this number

molar mass

the mass of one mole of any pure substance (atomic weight)

the molar mass of a compound must be calculated by adding the masses of each element in one mole of the compound

how do you calculate a compounds molar mass

molar volume

the volume occupied by one mole of gas at standard temperature and pressure

22.4 L

what is the molar volume of every gas

stoichiometry

that portion of chemistry dealing with numerical relationships in chemical reaction

the limiting reactant is the reactant that limits the extent of the reaction and determines the amount of product produced. it is used up first in a reaction, determines the amount of other reactants involved in the reaction, and used in stoichiometry calculations. the excess reactant os the substance that is not used up completely in a reaction it is useful because it allows the limiting reactant

what are the limiting reactant and excess reactant of a chemical reaction?

limiting reaction

the reactant that limits the extent of the reaction and determines the amount of product produced

excess reactant

the substance that is not used up completely in a reaction

1. gases consists of small particles separated from one another by empty space

2. the motion of particles in a gas is rapid, constant, and random

3. all collisions between particles in a gas are perfectly elastic

how does the kinetic molecular theory describe gases?

pressure

force per unit area

barometer

what instrument is used to measure air pressure ?

manometer

what instrument is used to measure the pressure of a gas in a closed container?

daltons law of partial pressures

the total pressure of a mixture of gases is equal to the sum of the partial pressures of each component of the mixture

boyles law

the volume of a given amount of gas held at a constant temperature varies inversely with the pressure

charles law

the volume of a fixed mass of gas is directly proportional to its kelvin temperature at constant pressure

gay lussac’s law

the pressure of a given mass of gas varies directly with the kelvin temperature when the volume remain constant

combined gas law

the law that states the relationship among pressure, volume, and temperature of a fixed amount of gas

ideal gas law

describes the ideal behavior of an ideal gas in the terms of the pressure, volume, temperature, and number of moles of a gas present

solutions

homogenous mixtures contains two or more substances called the solute and the solvent

the solute dissolves in the solvent. the solvent is the component that does the dissolving and the solute is the component that is dissolved

how are the solute and solvent of a solution related

solute

the component that is dissolved

solvent

the component that does the dissolving

if two solutions are alike in terms of the bonding and polarity of their particles, they will dissolve in each other ionic and polar solutes can only dissolve in polar solvents. nonploar solutes can only dissolve in non polar solvents.

explain the saying like dissolves like

miscible

describes two liquids that are voluble in each other

immiscible

describes two liquids that can be mixed together but separate shortly after you cease mixing them

soluble

describes a substance that dissolves in a given solvent

insoluble

describes a substance that does not dissolve in a given solvent

1. stirring the mixture

2. increasing the surface area of the solute

3. increasing the temperature

list 3 factors that can increase the rate of salvation

solubility

the maximum amount of solute that will dissolve in a given amount of solvent at a specific temperature and pressure

unsaturated solutions

contains less dissolved solute for a given temperature and pressure than a saturated solution

saturated solutions

contains the maximum amount of dissolved solute for a given amount of solvent at a specific temperature and pressure

supersaturated solutions

contains more dissolved solute than a saturated solution at the same temperature

temperature affects the solubility of all substances. for most solid and liquid solutes solubility increases as temperature increases. for most gases solutes, solubility decreases as temperature increases. pressure affects the solubility of gaseous solutes. thee solubility of a gas in any solvent increases as its external pressure.

how do pressure and temperature affect solubility

sites that at a given temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid

what is henrys law

concentration

a measurement of the amount of solute that is dissolved in given amount of solvent or solution

molarity

the number of moles of solute dissolved per liter of solutions; also known as molarity concentration

suspension

a type of heterogenous mixture whose particles settle out over time and can be separated from the mixture by filtration

colloid

heterogenous mixture containing particles larger than solution particles but smaller than suspension particles

energy

the capacity to do work or produce heat

kinetic energy

the energy of motion

potential energy

energy stored in an object due to its composition or position

law of conservation of energy

states that in any chemical or physical process, energy may change from one form to another but it is neither created nor destroyed

heat

a form of energy that flows from a warmer object to a cooler object

joule and calorie

what are two units of heat?

specific heat

the amount of heat required to raise the temperature of one gram of a given substance by one degree celsius= specific heat J/gC

delta T

change in temperature in degrees celsius. T final-T initial = triangle T

joule

the SI unit of heat and energy heat in J

m

mass in grams

enthalpy

the heat content of a system at constant pressure

enthalpy change

the amount of energy absorbed by a system as heat during a process at constant pressure

reaction is exothermic

what does it mean if the enthalpy change is negative

reaction is endothermic

what does it mean if the enthalpy change is positive

exothermic

reactions in which the system releases energy to the surroundings

endothermic

reactions in which the system, absorbed energy from the surroundings