chem paper 2

• Rate of reaction is the speed at which a reaction happens
• Rate is the change in a quantity divided by time
• Quantity can be the mass or volume of reactant used or product formed
• An experiment example is reacting hydrochloric acid and sodium thiosulfate
• Another experiment is measuring the volume of gas produced using a gas syringe
• Factors that increase the rate of reaction:

  • Increasing concentration of reactants in solution
  • Increasing pressure of gas reactants
  • Increasing surface area of solid reactants (crushing into a powder)
  • Increasing temperature, particles move more quickly and collide with more energy
• Adding a catalyst increases the rate by reducing activation energy needed
• Reversible reactions can go back to original reactants once products are made
• Le Chatelier's principle states that a system at equilibrium will adjust to counteract changes
• Increasing pressure favors the forward reaction, increasing concentration does the same for solutions
• Increasing temperature favors endothermic reactions
• Organic compounds have carbon forming the backbone of molecules
• Crude oil consists mostly of hydrocarbons, mainly alkanes
• Fractional distillation separates crude oil into different length alkanes
• Longer alkanes have higher boiling points and are more viscous
• Alkanes can be used as fuels and to make solvents, lubricants, detergents, and polymers
• Polymers are made from alkenes, which have a carbon-carbon double bond
• Alkenes can be tested with bromine water to check for unsaturation
• Cracking breaks longer alkanes into shorter alkanes and alkenes
• Alcohols end with -ol, can combust to produce carbon dioxide and water
• Short alcohols can mix with water to form a solution
• Oxidizing alcohols without combustion produces carboxylic acids
• Polymers are long-chain molecules made from repeating monomers
• Condensation polymerization joins monomers with two functional groups to form polymers
• Amino acids are the building blocks of proteins, can be polymerized to make polypeptides
• DNA is made from nucleotides and stores genetic code
• Starch is a natural polymer made from repeating units
• 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 involves a stationary phase (e.g., chromatography paper) and a mobile phase (e.g., water)
• RF value is a ratio used in chromatography to identify substances in a mixture
• Chemical tests for gases:

  • Hydrogen: burning splint produces a squeaky pop
  • Oxygen: relights a glowing splint
  • Carbon dioxide: turns lime water cloudy
  • Chlorine gas: bleaches damp blue litmus paper
• Flame tests for metals:

  • Lithium: crimson flame
  • Sodium: yellow flame
  • Potassium: lilac flame
  • Calcium: orange-red flame
  • Copper: green flame
• Carbonates react with acids to produce carbon dioxide gas