Kémia beugró Quiz

Unit Conversions

• Mass conversions: mg to g to kg (1000 mg = 1 g, 1000 g = 1 kg)
• Volume conversions: cm³ to dm³ to m³ (1000 cm³ = 1 dm³, 1000 dm³ = 1 m³)
• Amount of substance conversions: mmol to mol (1000 mmol = 1 mol)
• Density conversions: g/cm³ to kg/m³ (1 g/cm³ = 1000 kg/m³)
• Pressure conversions: MPa to kPa to Pa (1 MPa = 1000 kPa, 1 kPa = 1000 Pa)

Simple Calculation Tasks

• Mass percentage/mass fraction: Calculate mass fraction or mass percentage using the formula:
  Mass fraction = mass of substance / (mass of substance + mass of water) Mass percentage = (mass of substance / (mass of substance + mass of water)) * 100
• Molar percentage/molar fraction Calculate molar fraction or molar percentage using the formula: Molar fraction = moles of substance / (moles of substance + moles of water) Molar percentage = (moles of substance / (moles of substance + moles of water)) * 100
• Amount concentration: Amount concentration (c) = moles of substance / volume of solution (in liters)
• Density: Density (ρ) = mass of substance / volume of solution (in appropriate units)
• Mass concentration: Mass concentration (y) = mass of substance / volume of solution (in appropriate units)

Use of Mixing Equation

• Example calculations involve determining solute quantities in solutions given solution mass and percentage, density, and volume.

Formulas of Inorganic Compounds

• Key ionic compounds are provided for determining formulas
  • Nitrite (NO₂⁻), Nitrate (NO₃⁻), Iron (II) (Fe²⁺), Iron (III) (Fe³⁺), Carbonate (CO₃²⁻), Ammonium (NH₄⁺), etc.

Inorganic Chemistry

• Chlorine containing disinfectants include Sodium hypochlorite (NaOCl), Calcium hypochlorite (Ca(OCl)₂), and Hypochlorous acid (HOCl)
• Chlorine free disinfectants include Iodine, Ozone, and Hydrogen peroxide
• Ions that cause water hardness include Mg²⁺ and Ca²⁺
• "Heavy water" is water with a high concentration of Mg and Ca salts
• Bleach components include NaOCl and H₂O
• Chlorinated lime formula is Ca(OCl)₂

Kinetics

• Reaction rate describes the change in reactant/product concentrations per unit time
• Reaction rate can be influenced by temperature, pressure, and concentration
• Half-life is the time for a reactant concentration to decrease by half
• Catalysis speeds up reactions by opening alternative paths or lowering activation energy
• Inhibition counteracts catalysis by blocking the catalyst's active site

Electrolysis

• Electrolysis is using an electric current to cause a chemical change
• Galvanic cells use chemical reactions to generate electrical energy
• Anode is the negative electrode (where oxidation occurs)
• Cathode is the positive electrode (where reduction occurs)
• Cations move from anode to cathode through the salt bridge
• Anions move from cathode to anode through the salt bridge
• Oxidation involves the loss of electrons
• Reduction involves gaining electrons
• Components of pH measurement involve glass electrode (sensitive to H⁺ concentration) and a reference electrode (constant). Metal corrosion is the oxidation of metals to their oxides/sulfides. Local cells form at varying metal surface areas exposed to an electrolyte.

Equilibria

• Mass action law describes the equilibrium constant (K) for a reversible reaction
• Le Chatelier's Principle states how a system in equilibrium responds to changes in conditions. The system adjusts to minimize the effect of the change
• Arrhenius theory defines acids as substances that release H+ ions, and bases as substances that release OH- ions.
• Brönsted-Lowry theory defines acids as proton donors, and bases as proton acceptors.
• Ion Product of water(K_w) is the concentration of hydronium and hydroxide ions in water. pH is the negative logarithm of the hydrogen ion concentration. pOH is the negative logarithm of the hydroxide ion concentration.
• Weak acids partially dissociate in solution, while strong acids completely dissociate
• Substances that prevent large changes in pH are called buffers and are made of a weak acid/base and a salt. Hydrophilic salts dissolve in water and can be acidic or basic based on their chemistry.

Colloids

• Colloidal systems are mixtures with particles between 1 and 500 nm in size
• Emulsions are mixtures of immiscible liquids
• Suspensions involve finely dispersed solids in liquids
• Adsorption is a concentration change at a phase boundary
• Hydration involves a substance combining with water

Miscellaneous

• Chemical compounds result from combining atoms in specific proportions
• Isotopes are atoms of the same element with different numbers of neutrons but the same number of protons
• Valence electrons are located in the outermost electron shell; they are involved in forming chemical bonds.
• Hydrogen bonds occur when electronegative atoms (F, O, N) are bound to hydrogen

States of Matter

• Boiling point increases with external pressure because more energy is required to overcome the increased opposition
• Equilibrium vapor pressure is the pressure exerted by a vapor and the condensed phase at a given temperature in a closed system
• Factors affecting gas solubility in liquids are temperature, pressure, and the nature of the solute and solvent
• Osmosis is the movement of a solvent through a membrane to equalize solute concentrations
• Osmotic pressure is the pressure needed to halt osmosis
• Isotonic solutions have equal solute concentrations
• Hypertonic solutions have a higher solute concentration outside the cell than inside
• Hypotonic solutions have a lower solute concentration outside the cell than inside

Heat of Combustion

• Exothermic processes release heat to the surroundings
• Endothermic processes absorb heat from the surroundings
• Heat of combustion is the heat released when a substance reacts completely with oxygen