ESSLCE Chemistry Practice Flashcards

Practice flashcards covering general chemistry topics including atomic structure, bonding, gas laws, equilibrium, organic chemistry, and industrial chemistry based on the 2025 ESSLCE exam transcript.} Ready ESSLCE exam.

Relative Charge of an Electron

$$-1$$

Relative Charge of a Proton

$$+1$$

Relative Charge of a Neutron

$$0$$

Bohr's Model

A model of the atom where electrons move in circular orbits around the nucleus.

Periodicity

A regular repetition of chemical and physical properties in the Periodic Table.

Hydrogen Bonding

A bond formed by bonding a hydrogen atom to a highly electronegative element such as oxygen, nitrogen, or fluorine.

Covalent Bond

A bond formed between two or more atoms by the sharing of electrons.

Dipole-dipole Forces

The force that exists between polar molecules.

Van der-Waal's Forces

The weakest force when comparing intermolecular forces between molecules of similar molar masses.

Limiting Reactant

The reactant that is completely consumed when the reaction goes to completion.

Redox Reactions

Reactions in which electrons are transferred, whereas they are not transferred in non-redox reactions.

Equilibrium Constant Expression for $C(s) + CO_2(g) \rightleftharpoons 2CO(g)$

$\frac{[CO]^2}{[CO_2]}$, as solids like carbon are excluded from the expression.

Ideal Gas Law

A gas law that describes the behavior of gases using the variables: temperature, volume, pressure, and number of moles, expressed as $PV = nRT$.

Kinetic Theory of Gases (Assumptions)

Gas molecules are in random motion with no interactions and their average kinetic energies are dependent on temperature.

Boiling Chips

Materials added to water to ensure a smooth rate of evaporation and prevent bumping by providing nucleation sites.

Oxidation Number of Manganese in $KMnO_4$

$+7$ ($K = +1$, $O = -2 \times 4 = -8$, so $+1 + Mn + (-8) = 0 \implies Mn = +7$).

Law of Definite Composition

A law stating that a particular compound is always composed of the same elements in the same proportion by mass.

Chemical Equilibrium

A state where the rates of the forward and reverse reactions are equal.

Unsaturated Hydrocarbons

Compounds of carbon and hydrogen containing multiple bonds, such as double or triple bonds.

Methane ($CH_4$)

The main constituent of natural gas.

Tetrachloroethylene ($C_2Cl_4$)

A chemical used for dry cleaning to avoid the decrease in quality of clothes after washing with water.

Acidic Oxide

An oxide that reacts with water to form an acid.

Weak Acid

An acid that dissociates or ionizes only to a slight extent in aqueous solution.

Land Pollution

Pollution caused by the dumping of non-biodegradable wastes into the environment.

Law of Conservation of Mass

The principle that mass is neither created nor destroyed during a chemical reaction.

Quantum Numbers for the 5s Orbital

$n=5, l=0, m_l=0, m_s=\pm\frac{1}{2}$.

Pauli Exclusion Principle (Helium)

States that if the first electron in the 1s orbital has a specific spin, the second electron must occupy the same orbital with the opposite spin.

Transition Elements

Elements like Scandium ($Sc$) that have partially filled d-orbitals; $[Ar] 4s^2 3d^1$.

Le Chatelier’s Principle (Concentration Shift)

An equilibrium will shift to the right if the concentration of the reactants is increased and the concentration of the product is decreased.

Square Pyramidal

The molecular geometry of $BrF_5$ based on 5 bonding pairs and 1 lone pair of electrons.

Dihydric Alcohol

An alcohol molecule that contains exactly two hydroxyl ($-OH$) groups.

Lewis Base

An electron pair donor.

Percent Ionization

Defined as (amount ionized / initial concentration) $\times 100\%$, represented as $(\frac{x}{0.2}) \times 100\%$ in specific examples.

End Point

The point in acid-base titration at which the indicator changes color.

Equivalence Point

The point in acid-base titration where an acid has completely reacted with a base.

Faraday’s First Law of Electrolysis

Mathematically expressed as $m = \frac{Mit}{nF}$, relating the mass deposited ($m$) to current ($i$), time ($t$), and molar mass ($M$).

Soda-lime Glass

The most common type of glass, made by heating a mixture of silica ($SiO_2$), sodium carbonate ($Na_2CO_3$), and limestone ($CaCO_3$).

Nylon

A synthetic polyamide polymer used to make ropes, clothes, hair combs, and stockings.

Platinum ($Pt$)

The catalyst used in the Ostwald process for the production of $HNO_3$.

Biosphere

The component of the environment where photosynthesis takes place.

Greenhouse Effect

The trapping of infrared radiation by certain gases in the atmosphere, leading to an increase in Earth's temperature.

Renewable Resources

Natural resources that can be regrown or replenished naturally, such as crops.

Bronsted–Lowry Base

A substance that acts as a proton ($H^+$) acceptor, such as Ammonia ($NH_3$).

Food Preservation

A process that involves preventing the growth of bacteria and fungi and reducing the oxidation of fats through methods like canning or drying.

Electrolysis of Molten $NaCl$

The process with the overall reaction: $Na^+(l) + Cl^-(l) \rightarrow Na(l) + \frac{1}{2} Cl_2(g)$.

Electrolysis of Dilute $H_2SO_4$

A process where $H^+$ is discharged at the negative electrode (cathode) and reduced to $H_2$, while water is oxidized at the anode.