Mole Concept Practice Flashcards

Vocabulary-style flashcards covering the fundamental concepts of the Mole Concept, stoichiometry, redox reactions, and concentration units from the lecture materials.

Matter

Anything that occupies space and has mass is called matter.

Parmanus

The name given by Indian Philosopher Kanad ($600\,BC$) to very small, indivisible particles that compose matter.

Atoms

Tiny building blocks of matter described as hard and indivisible; the term was named by the Greek philosopher Democritus and means indivisible.

Dalton’s Atomic Theory

A theory stating that matter is made of indivisible atoms, all atoms of an element are identical, atoms cannot be created or destroyed, and atoms of different elements are different in nature.

Relative atomic mass (R.A.M.)

The mass of one atom of an element expressed with respect to a fixed standard, calculated today as the $\frac{\text{Mass of one atom of an element}}{\frac{1}{12} \times \text{Mass of one } C^{12} \text{ atom}}$.

Atomic mass unit (amu or Dalton)

A unit of mass equal to $\frac{1}{12}$ the mass of one atom of carbon-12 isotope, which is approximately $1.66 \times 10^{-24}\,g$ or $1.66 \times 10^{-27}\,kg$.

Unified mass (u)

The modern replacement for the atomic mass unit (amu).

Atomic mass

The mass of 1 atom of a substance, expressed in amu, and calculated as $\text{R.A.M.} \times 1\,amu$.

Molecular mass

The mass of 1 molecule of a substance, expressed in amu, calculated as $\text{Relative molecular mass} \times 1\,amu$.

Mole

The chemical counting SI unit defined as the amount of a substance that contains as many entities as there are atoms in exactly $0.012\,kg$ of the carbon-12 isotope.

Avogadro constant ($N_A$)

The number of entities in $1\,mol$, equal to $6.023 \times 10^{23}$ atoms present in $12\,g$ of $C-12$ isotope.

Gram Atomic Mass

The atomic mass of an element expressed in grams, or the mass of one mole ($6.02 \times 10^{23}$) of atoms.

Gram molecular mass

The molecular mass of a substance expressed in grams, or the mass of one mole of molecules.

Average/Mean Atomic Mass

The weighted average of the isotopic masses of an element’s naturally occurring isotopes: $A_x = \frac{a_1 x_1 + a_2 x_2 + \dots}{100}$.

Mean Molar Mass

The average molar mass of different substances in a container: $M_{avg} = \frac{n_1 M_1 + n_2 M_2 + \dots}{n_1 + n_2 + \dots}$.

Gay-Lussac’s Law of Combining Volume

The principle that gases combine in a simple ratio of their volumes, provided all measurements are done at the same temperature and pressure.

Avogadro’s hypothesis

The principle that equal volumes of all gases have an equal number of molecules at the same temperature and pressure conditions.

Standard Temperature and Pressure (S.T.P.)

Conditions defined as a temperature of $0^{\circ}\text{C} \text{ (} 273\,K \text{)}$ and a pressure of $1\,atm \text{ (} 760\,mm \text{ of } Hg \text{)}$.

Molar Volume

The volume of one mole of gas at STP, which is experimentally found to be $224\,dm^3$.

Empirical formula

A chemical formula that represents the simplest whole number ratio of various atoms present in a compound.

Molecular formula

A chemical formula that gives the actual and exact number of atoms of each element present in a molecule of a compound.

Limiting reagent

The reactant that is consumed first and limits the amount of product formed in a chemical reaction.

Excess reagent

The reactant remaining or left out after the limiting reagent has been completely consumed in a reaction.

Principle of Atom Conservation (POAC)

The principle stating that atoms are conserved in a chemical reaction, meaning the moles of atoms of a specific element in the reactants must equal the moles of atoms in the products.

Oxidation

The process involving the addition of oxygen, removal of hydrogen, increase in positive charge, increase in oxidation number, or removal of electrons.

Reduction

The process involving the removal of oxygen, addition of hydrogen, decrease in positive charge, decrease in oxidation number, or addition of electrons.

Oxidation Number

The imaginary or apparent charge developed over an atom of an element when it goes from its elemental free state to a combined state in molecules.

Oxidising agent (Oxidant)

A reagent that oxidizes others and reduces itself, undergoing a decrease in oxidation number or a gain of electrons.

Reducing agent (Reductant)

A reagent that reduces others and oxidizes itself, undergoing an increase in oxidation number or a loss of electrons.

Redox reaction

A reaction in which oxidation and reduction take place simultaneously, and the total increase in oxidation number equals the total decrease.

Disproportionation Reaction

A special redox reaction where the same element in a particular compound is oxidized and reduced simultaneously.

Comproportionation Reaction

A redox reaction in which an element from two different oxidation states is converted into a single oxidation state.

Solution

A homogeneous mixture of two or more substances that is clear, transparent, and cannot be separated by filtration.

Molarity ($M$)

A temperature-dependent concentration unit defined as the number of moles of a solute dissolved in $1\,dm^3$ of the solution.

Molality ($m$)

A temperature-independent concentration unit defined as the number of moles of solute dissolved in $1000\,g \text{ (} 1\,kg \text{)}$ of a solvent.

Mole fraction ($x$)

The ratio of the number of moles of a solute or solvent to the total number of moles present in the solution.

% weight by weight ($w/w$)

The mass of solute present in every $100\,g$ of solution: $\frac{\text{mass of solute in } g}{\text{mass of solution in } g} \times 100$.

% weight by volume ($w/v$)

The mass of solute present in every $100\,cm^3$ of solution: $\frac{\text{mass of solute in } g}{\text{volume of solution in } cm^3} \times 100$.

Parts Per Million (ppm)

A concentration term used for very small amounts of solute, defined as the number of parts of solute present in every $1$ million parts of the solution.