LO2 Flashcards
What are the three types of mixtures?
Solutions, colloids, suspensions
Mixtures can be classified based on the size of particles and their behavior in a medium.
What is the particle size range for colloids?
10-1000 Angstroms
Colloids are intermediate between solutions and suspensions.
What is the particle size for suspensions?
Larger than 10,000 Angstroms
Suspensions are heterogeneous and will separate over time.
How do colloids differ from solutions in terms of visibility?
Colloids are cloudy but uniform; solutions are clear and transparent
Light scattering is a key factor in distinguishing between these mixtures.
What are some common uses of colloids in nature and medicine?
Thickening agents, aerosols, emulsions, foams, gels, sols
Examples include lubricants, lotions, and blood products.
What is an alloy?
A mixture of two or more elements, at least one of which is a metal
Alloys can enhance the properties of the base metals.
What is the composition of amalgam?
Mercury (50%), silver (25%), tin (14%), copper (8%)
Amalgam is commonly used for dental fillings.
What is the main characteristic of brass?
More malleable than copper or zinc, corrosion resistant
Brass is used in musical instruments and plumbing.
What is the melting point range for solder?
90 to 450°C
Solder is used in electronics and plumbing to join metallic surfaces.
What defines oxidation in terms of electron transfer?
Loss of electrons
Oxidation can also involve the gain of oxygen or loss of hydrogen.
What is reduction in the context of redox reactions?
Gain of electrons
Reduction often involves the loss of oxygen.
What occurs during an addition reaction involving alkenes?
The double bond of the alkene partially breaks to add a reactant
This reaction allows for the formation of larger molecules.
Define a radical.
An atom, molecule, or ion with an unpaired valence electron
Radicals are highly chemically reactive.
What effect does increasing temperature have on reaction rates?
Increases the rate of reaction
Higher temperatures provide more kinetic energy to particles.
How does pressure affect the rate of reaction?
Increased pressure raises the number of collisions
Higher density of molecules leads to more frequent interactions.
What is the role of a catalyst in a chemical reaction?
Increases reaction rate without being consumed
Catalysts lower the activation energy needed for reactions.
What is the significance of enzyme specificity?
Enzymes catalyze specific reactions based on the active site structure
This specificity ensures that enzymes only interact with particular substrates.
Fill in the blank: A _______ is a substance that increases the rate of a reaction without being used up.
catalyst
Catalysts are crucial in both industrial processes and biological systems.
What is the effect of increasing the concentration of reactants on the reaction rate?
Increases the rate of reaction
More reactant particles lead to a higher chance of collisions.
What is the relationship between surface area and reaction rate?
Increasing surface area increases the rate of reaction
More exposed particles lead to more collisions.
What happens during a displacement reaction?
A more reactive metal displaces a less reactive metal from its compounds
This principle is illustrated by reactions involving metal salts.
How do halogens behave in redox reactions?
More reactive halogens displace less reactive halogens from their compounds
This behavior is evident in reactions with metal halides.
What by-product is produced in condensation polymerisation?
Water
This occurs when two monomers react, each having two functional groups.
What is the activation energy?
The minimum energy required for a reaction to occur
Only particles with sufficient energy can react upon collision.
What is the minimum energy required for particles to react called?
Activation energy
How does a catalyst affect activation energy?
Lowers the activation energy
Name one way a catalyst can lower activation energy.
By orienting the reacting particles for successful collisions
What is another method by which a catalyst can lower activation energy?
Reacting with reactants to form an intermediate
What are enzymes?
Proteins functioning as catalysts
What is the role of enzymes in chemical reactions?
Speed up reactions by lowering activation energy
What is the active site of an enzyme?
The region where the protein and substrate bind for the reaction
What is enzyme specificity?
The ability of an enzyme to only catalyze specific substrates
What hypothesis describes the mechanism of enzyme specificity?
Lock and key and induced fit hypotheses
How does temperature affect enzyme activity?
Increases the rate of enzyme-catalyzed reactions
What is the effect of a 100°C rise in temperature on enzyme activity?
Increases activity by 50 to 100%
What is optimum pH?
The most favorable pH value for enzyme activity
What happens to most enzymes at extremely high or low pH?
Complete loss of activity
How does light intensity affect the rate of photosynthesis?
Increases the rate until a limiting factor is in short supply
What is the relationship between light intensity and activation energy?
Greater intensity increases the likelihood of particles gaining required energy
What is electromagnetic radiation’s effect on reactions?
Increases the rate of reaction by giving particles more energy
How can electromagnetic radiation affect molecular bonds?
Causes bending or stretching, weakening them
What example illustrates the effect of UV light in a reaction?
Breaking Cl bonds in the chlorination of methane
