Exam 2

Question 1

Limiting reagent

Answer 1

the reactant that gets consumed first in a chemical reaction and therefore limits how much product can be formed

Question 2

Percent yield

Answer 2

the actual yield divided by the theoretical yield times 100

Question 3

Solubility

Answer 3

the ability of a solid, liquid, or gaseous chemical substance (referred to as the solute) to dissolve in solvent (usually a liquid) and form a solution.

Question 4

Solvation

Answer 4

the interaction of a solvent with the dissolved solute—in the case of water, solvation is often referred to as hydration.

Question 5

Dissociation

Answer 5

a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into other things such as atoms, ions, or radicals, usually in a reversible manner.

Question 6

Ionization

Answer 6

Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes.

Question 7

Electrolytes

Answer 7

a substance that dissociates in water into charged particles called ions. Positively charged ions are called cations. Negatively charged ions are called anions. Simply, an electrolyte is a substance that can conduct an electric current when melted or dissolved in water.

Question 8

Molarity

Answer 8

Amount of moles of a substance in a certain volume of solution.

M=n/v

Question 9

Concentration

Answer 9

The quantity of solute present in a given quantity of solution.

Question 10

Dilution

Answer 10

the addition of solvent, which decreases the concentration of the solute in a solution.

Question 11

Acid

Answer 11

A molecule or other species which can donate a proton or accept an electron pair in reactions.

Question 12

Base

Answer 12

A substance that can neutralize an acid by reacting with (accepting) hydrogen ions.

Question 13

Polyprotic acid

Answer 13

Polyprotic means “many protons”

Specific acids that are capable of losing more than one single proton (ionizable H+) per molecule in acid-base reactions.

Question 14

Monoprotic acid

Answer 14

An acid that will only donate one proton (ionizable H+)

Question 15

Neutralization

Answer 15

The reaction of an acid and a base, which forms water and salt

Question 16

Gas-evolution reaction

Answer 16

A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide

Question 17

Precipitation

Answer 17

The formation of a solid from a solution

Question 18

Redox reaction

Answer 18

Reaction that involve the transfer of electrons from one species to another

Question 19

Oxidizing agent

Answer 19

A chemical species that tends to oxidize other substances.

Oxygen, hydrogen peroxide, halogens

Question 20

Reducing agent

Answer 20

a substance that is oxidized by donating electrons

Potassium, calcium, barium, sodium, and magnesium

Question 21

Oxidation

Answer 21

a process in which a chemical substance changes because of the addition of oxygen.

Question 22

Reduction

Answer 22

the process of an atom or compound gaining one or more electrons

Question 23

Combustion reaction

Answer 23

occur when a compound, usually one containing carbon, combines with the oxygen gas in the air. This process is commonly called burning. Heat is the most-useful product of most combustion reactions.

Question 24

*Oxidation identification rules

Question 25

Gases under normal conditions

Answer 25

He, Ar, Ne, N2, H2, O2, O3, F2, Cl2, Kr, Xe.

Question 26

*Pressure

Answer 26

the force exerted per unit area.

Measured using barometer or manometer.

Question 27

Pressure & volume

Answer 27

Inverse = when volume increases, pressure decreases (constant temp)

Question 28

Temperature & volume

Answer 28

Directly proportional = volume increases as temperature increases (constant pressure)

Question 29

Moles & volume

Answer 29

Directly proportional at constant temperature and pressure.

Question 30

Ideal Gas Equation

Answer 30

PV=nRT
P = pressure
V = volume
n = moles
R = Gas constant
T = temperature

Question 31

Dalton’s Law of Partial Pressure

Answer 31

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

Ptotal = Pg1 + Pg2 + Pg3 …

Question 32

Kinetic Molecular Theory of Gases

Answer 32

Gases consist of particles (molecules or atoms) that are in constant random motion.

Gas particles are constantly colliding with each other and the walls of their container.

These collisions are elastic; that is, there is no net loss of energy from the collisions.

Question 33

Graham’s Law to find the molar mass of an unknown gas

Answer 33

the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight.

Using the given effusion rates of the known reference gas (Rate₁) and the unknown gas (Rate₂) along with the molar mass of the known reference gas (M₁), substitute these values into the equation: M₂ = (Rate₁ / Rate₂)² * M₁ Calculate M₂ to determine the molar mass of the unknown gas.

Question 34

Real vs. ideal gases

Answer 34

Real gases follow Ideal Gas Law only under conditions of high temperature and low pressure

An ideal gas is a theoretical gas composed of many randomly moving particles that are not subject to interparticle interactions. A real gas is simply the opposite; it occupies space and the molecules have interactions.

Question 35

Energy

Answer 35

the capacity to supply heat or do work. The ability to do work.

Question 36

Potential energy

Answer 36

the energy stored in the bonds of chemical compounds

PE = Fx

F = opposing force
x = distance moved

PE=mgh
m = mass
g = gravity acceleration
h = object’s height

Question 37

Kinetic energy

Answer 37

energy possessed by an object in motion. The earth revolving around the sun, you walking down the street, and molecules moving in space all have kinetic energy. Kinetic energy is directly proportional to the mass of the object and to the square of its velocity:

KE=1/2mv^2

m = mass
v = velocity

Question 38

Thermal energy

Answer 38

refers to the energy contained within a system that is responsible for its temperature. Heat is the flow of thermal energy.

q = mcΔT

Question 39

Chemical energy

Answer 39

the energy stored in the bonds of chemical compounds

Question 40

Heat

Answer 40

The flow of thermal energy. The amount of energy that is transferred from one system to its surroundings because of a temperature difference.

q = mcΔT

Question 41

Work

Answer 41

the energy needed to move against a force.

a change in volume against a pressure. ( Pressure is force divided by area, so convince yourself that P x V has the same units as F x d.) For instance, atmospheric pressure is constant at ~1 atm.

Question 42

System

Answer 42

our chemical reaction. That includes the reactants, products, catalysts, transition states, intermediates, solvents, and anything else. The surroundings are everything else.

Question 43

Surroundings

Answer 43

Everything that surrounds and potentially reactions with the system itself.

Question 44

Endothermic

Answer 44

endothermic reactions absorb energy from the surrounding that is in the form of heat.

Question 45

Exothermic

Answer 45

releases energy into the surrounding of the system.

Question 46

Enthalpy

Answer 46

the heat change occurred when one mole of substance is formed from its constituent elements in their standard state,

Question 47

Specific heat

Answer 47

the amount of heat that must be added to one unit of mass of the substance in order

Question 48

Heat capacity

Answer 48

physical property of matter defined as the amount of heat needed to cause a unit change in temperature in a given mass of material

Question 49

Calorimetry

Answer 49

the process of measuring the amount of heat released or absorbed during a chemical reaction. By knowing the change in heat, it can be determined whether or not a reaction is exothermic (releases heat) or endothermic (absorbs heat).

Question 50

First Law of Thermodynamics

Answer 50

energy cannot be created or destroyed; it can only be converted from one form to another. The First Law is used to categorise ‘the performance of cyclic conversion systems like fossil-fired, steam power cycles or geothermal cycles.

Question 51

Hess’s Law

Answer 51

If a chemical equation can be written as the sum of several other chemical equations, the enthalpy change of the first chemical equation equals the sum of the enthalpy changes of the other chemical equations.

if a process can be expressed as the sum of two or more steps, the enthalpy change for the overall process is the sum of the ΔH values for each step.