Unit 1: Matter and Mixtures Quiz

Unit 1: Matter and Mixtures

• Matter has mass and volume.
• Matter is categorized as either a pure substance or a mixture.
• Pure substances are further divided into elements and compounds.
• Mixtures are combinations of two or more pure substances not chemically bonded.
• Mixture separation methods include filtration (particle size), distillation (boiling point), centrifuging (density), magnetism (Fe, Co, Mn), and chromatography (polarity).
• Physical properties describe matter without changing its identity, such as taste, smell, molar mass, density, melting point, boiling point, and freezing point.
• Chemical properties describe how matter reacts with other substances, such as reactions with oxygen, acids, and bases, burning.
• Density (D) = mass (m) / volume (v).
• A compound is two or more different elements bonded chemically.
• The Law of Constant Composition states a compound always contains the same elements in the same proportion.
• Seven diatomic elements are Br, I, N, Cl, H, O, F.
• Heterogeneous mixtures are not uniform throughout.
• Homogeneous mixtures are uniform throughout.
• Prefixes: kilo (k) = 10³, centi (c) = 10^-2, milli (m) = 10^-3.
• Significant figures: Addition/subtraction—least decimal places; Multiplication/division—least significant figures.

Unit 2: Atoms and Compounds

• Law of Constant Composition (Definite Proportions): Compounds have definite elemental ratios.
• Subatomic particles—electrons, protons, and neutrons—have specific charges, relative charges, masses, and locations within the atom.
• Atomic mass is a weighted average of isotopes.
• Compounds, combinations of elements, have unique chemical and physical properties.
• Types of compounds include molecular (nonmetals bonded) and ionic (metal and nonmetal bonded).
• Acids start with hydrogen, while organic compounds contain carbon and hydrogen.
• Molecular compound nomenclature: Name the more metallic element first, drop the ending of the second and add -ide, avoid mono- prefix if it's not needed and avoid reducing subscripts.
• Binary molecules use Greek prefixes (mono- one; di- two...deca- ten) for element quantities.
• Ions are charged atoms (cations positive, anions negative).
• In ionic compound nomenclature, write the metal first, use charges for ratios, and drop the ending (if binary) or add roman numerals for multiple charges.
• Acid nomenclature: "Hydro" + anion ending (-ic) or use polyatomic anion.
• Organic compound nomenclature: Prefixes indicate carbon quantity (meth- 1, eth-2...), and alkanes end in "-ane." Alcohols end in "-ol."

Unit 3: Chemical Reactions

• Law of Conservation of Mass: Mass is conserved in chemical reactions.
• Synthesis (A + B → AB), Decomposition (AB → A + B), Single Replacement (AB + C → AC + B), Double Displacement (AB + CD → AD + CB), Combustion (CxHy(Oz) + O2 → CO2 + H2O) are reaction types.
• Empirical formula multiplier = Molar mass / Empirical formula mass.
• Percent yield = (experimental mass / theoretical mass) x 100.
• Limiting reactant problems: Divide reactant moles by their coefficients, smallest is limiting.
• Solve for product/reactant masses using stoichiometry and limiting reactant.

Unit 4: Electrolytes and Reactions

• Strong electrolytes conduct electricity well and dissociate completely in water. This includes soluble ionic compounds, strong acids (HCl, HBr, HI, HNO3, H2SO4, HClO4, HClO3), and strong bases (LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2).
• Weak electrolytes conduct electricity poorly and dissociate incompletely. Weak acids and weak bases belong to this category.
• Non-electrolytes do not conduct electricity and usually are covalent compounds, or insoluble ionic compounds.
• Metathesis reactions (double displacement) occur when a precipitate, water, or gas is formed.
• Acid-base reactions form a salt and water.
• Oxidation-reduction (redox) reactions involve electron transfer (LEO goes GER - Loss of Electrons is Oxidation, Gain of Electrons is Reduction).
• Oxidation states: Pure elements are zero; common ions have fixed states.
• Activity series lists metals in order of decreasing ease of oxidation; the less reactive element is reduced.
• Molarity (M) = moles of solute / liters of solution.

Unit 5: Thermodynamics and Calorimetry

• Temperature is the average kinetic energy, while heat is total energy.
• Endothermic reactions absorb energy, exothermic reactions release energy.
• Energy changes (∆H) in chemical reactions can be calculated graphically (∆H = Hproducts - Hreactants).
• Joule stoichiometry: Coefficients relate to moles. States matter.
• Calorimetry: Heat capacity (∆H = mc∆T) is the energy to raise 1 g of substance by 1˚C.
• Calculations for heat of solution/neutralization involve (m)(C)(∆T) calculations, water heat capacity is often 4.184J/g˚C
• Bomb calorimeter: ∆H = Cp(cal) ∆T (including the calorimeter's contribution).
• Hess's Law: Manipulate equations to find ∆H of an overall reaction.
• Heats of formation (∆Hf): Energy to make 1 mole of compound from elements at standard state (pure elements = 0 ∆Hf).
• Bond energies: Calculate ∆H by summing bond breaking and bond formation energies.

Unit 19: Thermodynamics and Spontaneity

• Thermodynamically feasible processes (spontaneous) have two driving forces: lower energy (exothermic, - ∆H), and increased disorder (higher entropy, +∆S).
• Entropy (S) is the measure of system disorder; it increases with higher number of atoms/molar mass, liquid/solid dissolution, gas volume, and temperature.
• Spontaneous processes: ∆G˚ = ∆H˚ - T∆S˚.
  • ∆H˚, ∆S˚ positive and negative values determine how temperature affects whether a reaction is spontaneous.

Unit 10: Ideal Gas Laws

• Gases at the same temperature have the same kinetic energy.
• Dalton's Law: PTotal = Pgas A + Pgas B...
• Manometers measure gas pressure. Combined Gas Law (PV = nRT), Dalton's Law, and Raoult's Law are important concepts to remember for this unit.
• Graham's Law: The rate of gas effusion is inversely proportional to the square root of its molar mass.
• Real gases deviate from ideal behavior at high pressure and low temperature.