Chem 6 to

What is chemical nomenclature?

Systematic method for naming chemical compounds based on composition and standardized rules.

What is an oxidation number?

Number assigned to an atom based on electron-counting rules -> identifies compound formulas and variable metal oxidation states.

What are the fundamental rules for assigning oxidation numbers?

Free element = 0 -> Group 1 metals = +1 -> Group 2 metals = +2 -> Oxygen = -2 (-1 in peroxides) -> Halogens = -1 -> Hydrogen = +1 with non-metals / -1 with metals.

What is the rule for the sum of oxidation numbers in neutral compounds versus polyatomic ions?

Neutral compound = 0 -> Polyatomic ion = net charge of the ion.

What do Roman numerals in chemical names indicate?

Oxidation state of transition or variable-valency metal cation -> does not indicate atom quantity.

What is a binary ionic compound and how is it named?

Compound composed of metal cation (+) and non-metal anion (-) held by electrostatic attraction -> Metal name + non-metal root ending in "-ide".

What is a polyatomic ion?

Group of two or more covalently bonded atoms carrying an overall electrical charge.

How do the suffixes "-ate" and "-ite" distinguish polyatomic oxyanions?

"-ate" = more oxygen atoms (e.g., NO3- nitrate) -> "-ite" = fewer oxygen atoms (e.g., NO2- nitrite).

What are the Greek numerical prefixes for molecular compounds from 1 to 10?

1 = mono- -> 2 = di- -> 3 = tri- -> 4 = tetra- -> 5 = penta- -> 6 = hexa- -> 7 = hepta- -> 8 = octa- -> 9 = nona- -> 10 = deca- (mono- omitted on first element).

How are metal oxides named versus non-metal oxides?

Metal oxides = ionic -> Metal name + oxide; Non-metal oxides = covalent -> Greek prefixes + oxide.

How are oxides classified by acid-base behavior?

Basic (react with acids) -> Acidic (react with bases) -> Amphoteric (react with both acids and bases) -> Neutral (react with neither).

How are binary acids named?

"Hydro-" + non-metal root + "-ic acid" (e.g., HCl(aq) -> hydrochloric acid).

How are oxyacids named based on their polyatomic anion?

Anion ending in "-ate" -> "-ic acid" (e.g., HNO3 -> nitric acid); Anion ending in "-ite" -> "-ous acid" (e.g., HNO2 -> nitrous acid).

What is an inorganic base and how is it typically named?

Proton (H+) acceptor -> Metal name + hydroxide (e.g., NaOH); NH3 acts as a base without OH- in its formula.

What is a chemical salt and how is it formed?

Ionic compound formed by replacing acid H+ with metal or ammonium ions -> Acid + Base -> Salt + Water.

What is a hydrate and how is it named?

Ionic compound containing trapped water of crystallization within crystal lattice -> Compound name + numerical prefix + "hydrate" (e.g., CuSO4·5H2O -> copper(II) sulfate pentahydrate).

What is relative atomic mass (Ar)?

Weighted average mass of an atom of an element compared to 1/12 the mass of a carbon-12 atom -> dimensionless.

Why is chlorine's relative atomic mass 35.45?

Natural isotopic abundance weighted average -> 75% 35Cl + 25% 37Cl -> (3575 + 3725)/100 = 35.45.

What is relative molecular mass (Mr)?

Mass of a molecule compared to 1/12 mass of carbon-12 atom -> sum of all Ar values in covalent molecule -> dimensionless.

What is relative formula mass and when is it used instead of Mr?

Sum of Ar values for giant ionic lattice compounds (e.g., NaCl) -> used because discrete molecules do not exist. [ASSOCIATE WITH A DIAGRAM]

What is the mole?

SI unit for amount of substance (n) -> contains exactly 6.02214076 x 10^23 elementary entities.

What is Avogadro's constant (NA)?

Number of specified particles per mole -> 6.022 x 10^23 mol^-1.

What formula relates number of particles (N) to moles (n)?

N = n * NA -> n = N / NA.

What is molar mass (M) and its unit?

Mass of one mole of a substance -> unit: g/mol -> M = m / n.

How do relative mass (Mr) and molar mass (M) differ?

Identical numerical value -> Mr has no unit, M has unit g/mol.

What formulas connect mass (m), moles (n), and molar mass (M)?

n = m / M -> m = n * M -> M = m / n.

What formula calculates the total number of particles (N) directly from mass?

N = (m / M) * NA.

What is an empirical formula?

Simplest whole-number ratio of atoms of each element in a compound.

What is a molecular formula?

Actual number of atoms of each element in a molecule -> whole-number multiple of empirical formula.

Can empirical and molecular formulas be identical?

Yes -> occurs when elemental subscript ratios cannot be further reduced (e.g., H2O, C5H9).

What are the sequential steps to determine an empirical formula from element masses?

Determine mass of each element -> convert mass to moles (n = m/M) -> divide all moles by smallest mole value -> scale to whole numbers if fractional -> write empirical formula.

How are non-integer mole ratios handled in empirical formula calculations?

Multiply all mole ratios by smallest common factor to yield integers -> e.g., 1 : 1.5 -> x2 -> 2 : 3.

How is an empirical formula determined from percentage composition?

Assume 100 g total sample -> convert % directly to grams -> convert grams to moles (n = m/M) -> divide by smallest mole value -> write formula.

What formula calculates the molecular formula multiplier (k)?

k = Molar mass / Empirical formula mass -> Molecular formula = (Empirical formula) * k.

What law governs balancing chemical equations?

Law of Conservation of Mass -> atom count of each element on reactant side must equal product side.

What is the fundamental rule when balancing chemical equations?

Adjust stoichiometric coefficients preceding formulas -> NEVER alter chemical subscripts.

What do the state symbols (s), (l), (g), and (aq) denote?

(s) = solid -> (l) = liquid -> (g) = gas -> (aq) = aqueous (dissolved in water).

What is stoichiometry?

Quantitative study of reactant and product amounts in a chemical reaction based on balanced equations.

What is a mole ratio?

Ratio of coefficients of substances in a balanced equation -> converts moles of known substance to required substance.

What formula calculates moles of substance B from moles of substance A?

n_B = n_A * (nu_B / nu_A) -> where nu represents stoichiometric coefficient.

What is the sequence for mass-to-mass stoichiometry calculations?

Mass A -> divide by M_A -> Moles A -> multiply by mole ratio (nu_B / nu_A) -> Moles B -> multiply by M_B -> Mass B.

What is a limiting reagent?

Reactant completely consumed first in a reaction -> halts product formation -> dictates maximum product yield.

What is an excess reagent?

Reactant remaining unreacted after limiting reagent is completely exhausted.

How is the limiting reagent identified by product yield?

Calculate moles of product formed by each initial reactant -> reactant yielding lowest product amount = limiting reagent.

How is the limiting reagent identified by coefficient ratio?

Divide available moles of each reactant by its stoichiometric coefficient (n / nu) -> lowest value = limiting reagent.

How is the remaining excess reagent calculated?

Initial moles of excess reagent - consumed moles (moles of limiting reagent * stoichiometric requirement).

What is theoretical yield?

Maximum amount of product calculated from limiting reagent using balanced equation assuming complete reaction without loss.

What is actual yield?

Amount of product experimentally collected and measured in the laboratory.

Why is actual yield often lower than theoretical yield?

Incomplete reactions -> competing side reactions -> mechanical loss during filtering, separation, or purification.

What is percentage yield and its mathematical formula?

Quantitative measure of reaction efficiency -> % Yield = (Actual yield / Theoretical yield) * 100.

How is actual yield calculated from percentage yield and theoretical yield?

Actual yield = (% Yield / 100) * Theoretical yield.

How is theoretical yield calculated from percentage yield and actual yield?

Theoretical yield = Actual yield / (% Yield / 100).