Chemistry Basics and Lab Techniques (Lecture Notes)

A comprehensive set of practice flashcards in Q&A format covering basic concepts, properties of matter, separation techniques, atomic structure, isotopes, nomenclature, stoichiometry, gas laws, common compounds, and applied chemistry terms.

What is the smallest unit of an element?

An atom.

What is an element?

A pure substance consisting of one type of atom.

What is a compound?

Two or more elements chemically bonded.

What is a molecule?

Atoms bonded together (e.g., O2, CO2).

What are macromolecules?

Large molecules such as proteins and DNA.

What are isotopes?

Atoms with the same number of protons but different numbers of neutrons.

Which subatomic particle carries a positive charge?

A proton.

Which subatomic particle has no charge?

A neutron.

Which subatomic particle carries a negative charge?

An electron.

How do mass and weight differ?

Mass is constant; weight depends on gravity.

What is an extensive property?

A property that depends on the amount of substance (e.g., mass, volume).

What is an intensive property?

A property that does not depend on amount (e.g., density, boiling point).

What is a physical property?

Observed without changing the identity of the substance (e.g., color, melting point).

What is a chemical property?

A property that describes how a substance reacts or changes (e.g., rusting, oxidation).

Give an example of a chemical property involving oxidation.

Peeled apple turning brown due to oxidation.

What are the four states of matter?

Solid, liquid, gas, plasma.

What characterizes a solid?

Definite shape and definite volume.

What characterizes a liquid?

Definite volume; takes the shape of its container.

What characterizes a gas?

Expands; no fixed volume or shape.

What is plasma?

An ionized gas (found in stars and neon lights).

What happens in evaporation as a separation technique?

Removes solvent to obtain a solid from a solution (e.g., salt from seawater).

What is decantation?

Separating liquid from a denser solid or liquid.

What is filtration?

Solid is separated from liquid; results in a residue and a filtrate.

What is distillation?

Separates liquids by boiling point; can be simple or fractional.

What is sublimation?

Solid changes directly to a gas.

What is chromatography?

Separation by solubility and capillary action (e.g., ink pigments).

What does magnetism separate in mixtures?

Magnetic metals (e.g., iron; magnetic separation).

What is decanting immiscible liquids used for?

Quickly separates liquids like water and oil.

What is the atomic number Z?

The number of protons in the nucleus.

What is the mass number A?

Protons plus neutrons (A = Z + N).

What are neutrons (N) in terms of A and Z?

Neutrons = A − Z.

What is the relationship between electrons and protons in a neutral atom?

Electrons equal the number of protons.

What are isotopes in terms of Z and N?

Isotopes have the same Z (protons) but different N (neutrons).

Which isotope is used for dating fossils?

Carbon-14.

Which isotope is mentioned for cancer radiation therapy?

Carbon-60.

Which isotope is used to treat thyroid cancer?

Iodine-131.

Which isotope is used to locate brain tumors?

Technetium-99.

Which isotope helps determine damage in heart tissue?

Thallium-201.

Which isotope is used to determine the age of sediments?

Uranium-238.

Which isotope is used as nuclear fuel in power plants?

Uranium-235.

Which isotope is used to monitor organs during PET scans?

Carbon-11.

What is an ionic compound?

A compound formed from a metal and a nonmetal; cation first, anion second (e.g., NaCl).

What is a covalent compound?

A compound formed from nonmetals; use prefixes (mono-, di-, tri-). (e.g., PCl3).

Give examples of ionic compounds by formula.

KF (potassium fluoride), BeO (beryllium oxide), HI (hydroiodic acid).

What acids are listed and their formulas?

HClO3 (chloric acid), H2SO4 (sulfuric acid).

What are the iron compounds listed and their names?

FeCl3 = iron(III) chloride; FeO = iron(II) oxide.

What does the Law of Conservation of Mass state?

Mass is neither created nor destroyed in a chemical reaction.

What is balancing of equations about?

Ensuring the same number of atoms of each element on both sides.

What are coefficients in a chemical equation?

Numbers placed before formulas that show mole ratios.

What is a limiting reactant?

The reactant that is consumed first and limits product formation.

What is an excess reactant?

The reactant that remains after the reaction goes to completion.

In the CH4 + 2O2 → CO2 + 2H2O example, how many moles of O2 are required to burn 3 moles of CH4?

6 moles of O2.

What are moles in chemical calculations?

Moles = mass ÷ molar mass; mass = moles × molar mass.

What is an empirical formula?

The simplest whole-number ratio of elements in a compound.

What is a molecular formula?

A formula that shows the actual number of each type of atom in a molecule; a multiple of the empirical formula.

Given 52.14% C, 13.13% H, 34.73% O and molar mass 46 g/mol, what is the empirical formula and molecular formula?

Empirical formula: CH2O (30 g/mol). Multiplier: 46 ÷ 30 ≈ 1.5 → 2. Molecular formula: C2H4O2 (acetic acid).

What is Boyle’s Law?

P1V1 = P2V2 (volume inversely related to pressure at constant temperature).

What is Charles’s Law?

V1/T1 = V2/T2 (volume proportional to temperature at constant pressure).

What is Gay-Lussac’s Law?

P1/T1 = P2/T2 (pressure proportional to temperature at constant volume).

What is Avogadro’s Law?

Volume is proportional to the number of moles at constant T and P (V ∝ n).

What is the Ideal Gas Law?

PV = nRT.

What is galena and its formula?

Galena = PbS.

What is Baking Soda’s chemical formula?

NaHCO3.

What is Bleach’s chemical formula?

NaClO.

What is Caustic Soda’s chemical formula?

NaOH.

What is Dry Ice’s chemical formula?

CO2 (solid).

What is Milk of Magnesia’s formula?

Mg(OH)2.

What is Muriatic Acid’s formula?

HCl.

What is Table Salt’s formula?

NaCl.

What is Vinegar’s formula?

CH3COOH.

What is Laughing Gas’s formula?

N2O.

What is TNT’s formula?

C6H2(NO2)3CH3.

What is Methane’s formula?

CH4.

What is an oxidizer?

A substance that provides oxygen to cause or sustain combustion.

What are common oxidizers given as examples?

Hydrogen peroxide (H2O2) and potassium nitrate (KNO3).

What is the memory aid for oxidizers?

“Oxy = oxygen giver.”

What is a surfactant?

A surface-active agent that reduces surface tension between two substances (often oil and water).

What is an emulsifier?

A surfactant that helps mix immiscible liquids (e.g., lecithin in mayonnaise).

What is an emollient?

Substances that soften and moisturize the skin, preventing water loss (e.g., petroleum jelly, glycerin).

What is preservation in chemistry?

Process of preventing decomposition, spoilage, or microbial growth (refrigeration, drying, salting, preservatives like sodium benzoate).