Chemistry paper 2

• Rate of reaction is the change in a quantity divided by time
• Quantity can be the reactant used or product formed, measured in mass or volume of gas
• An experiment example is reacting hydrochloric acid and sodium thiosulfate in a conical flask over a cross
• Turbidity increases as the product forms and the solution turns cloudy
• Rate can be found by drawing a tangent at a specific point on a graph of gas volume vs. time
• Factors that increase the rate of reaction:

  • Increasing concentration of reactants in solution
  • Increasing pressure of gas reactants
  • Increasing surface area of solid reactants by crushing into a powder
  • Increasing temperature, which also increases the energy of collisions
  • Adding a catalyst to reduce activation energy
• Reversible reactions can go back to their original reactants once products are made
• In a closed system, equilibrium is reached when rates of forward and reverse reactions are the same
• Le Chatelier's principle states that a system at equilibrium will adjust to counteract any changes
• Changes in pressure, concentration, or temperature can shift the position of equilibrium
• Organic compounds have carbon forming the backbone of molecules
• Crude oil consists mostly of hydrocarbons, mainly alkanes
• Alkanes have a general formula CNH2N+2 and end with "-ane"
• Fractional distillation separates crude oil into different length alkanes based on boiling points
• Longer alkanes have higher boiling points and are more viscous, while shorter alkanes are more flammable
• Cracking breaks longer alkanes into shorter alkanes and alkenes
• Alkenes have a carbon-carbon double bond and can be tested with bromine water
• Alcohols end with "-ol" and can be oxidized to form carboxylic acids
• Polymers are long-chain molecules made from repeating monomers, can be formed through addition or condensation polymerization
• Amino acids are the building blocks of proteins and can be polymerized to form polypeptides
• DNA is made from nucleotides and starch is a natural polymer
• DNA is made from two polymers that spiral around each other in a double helix
• DNA is made from four different monomers called nucleotides
• Starch is a natural polymer with glucose as the monomer
• Cellulose is a polymer made from beta glucose
• Proteins have amino acids as their monomers
• Melting point or boiling point can be used to determine if a substance is pure
• Formulation is a mixture designed for specific purposes with specific quantities of substances
• Chromatography is used to separate substances in a mixture
• Chromatography uses a stationary phase and a mobile phase
• RF value is a ratio used in chromatography to identify substances
• Chemical tests for hydrogen, oxygen, carbon dioxide, and chlorine gases
• Flame tests for lithium, sodium, potassium, calcium, and copper
• Chemical tests for metals in solutions using sodium hydroxide
• Carbonates react with acids to produce carbon dioxide gas
• Testing for halide ions using silver nitrate solution and nitric acid
• Testing for sulfate ions using barium chloride and hydrochloric acid
• Instrumental methods are used in labs for chemical analysis
• Flame emission spectroscopy is used to identify metal ions
• Atmospheric chemistry and the greenhouse effect