paper 2 Flashcards
(33 cards)
What is the rate of reaction?
The speed at which reactants are converted into products.
What factors affect the rate of reaction?
Temperature, concentration, surface area, catalysts, and pressure (for gases).
What is the collision theory?
Reactions occur when particles collide with sufficient energy (activation energy).
How does temperature affect reaction rate?
Higher temperature increases particle energy, leading to more frequent and energetic collisions.
How does concentration affect reaction rate?
Higher concentration increases the number of particles in a given volume, leading to more collisions.
How does surface area affect reaction rate?
A larger surface area increases the number of exposed particles, increasing collision frequency.
What is a catalyst?
A substance that speeds up a chemical reaction without being used up.
What is a hydrocarbon?
A compound made of hydrogen and carbon atoms only.
What is the general formula for alkanes?
CnH2n+2.
What is the difference between alkanes and alkenes?
Alkanes are saturated (single bonds), while alkenes are unsaturated (contain at least one double bond).
What is cracking?
Breaking down long-chain hydrocarbons into smaller, more useful molecules using heat and a catalyst.
What are the products of complete combustion of a hydrocarbon?
Carbon dioxide and water.
What are the products of incomplete combustion of a hydrocarbon?
Carbon monoxide and water, sometimes producing soot (carbon particles).
What is a pure substance?
A single element or compound, not mixed with any other substance.
What is a formulation?
A mixture designed for a specific purpose, with precise amounts of components (e.g., medicines, fuels).
What is chromatography?
A technique used to separate mixtures based on differences in solubility.
How can you identify a substance using chromatography?
Compare Rf values to known substances.
What is the test for hydrogen gas?
A burning splint produces a squeaky pop.
What is the test for oxygen gas?
A glowing splint relights in oxygen.
What is the test for carbon dioxide?
Limewater turns cloudy when CO₂ is bubbled through it.
What is the test for chlorine gas?
Damp litmus paper is bleached white in chlorine gas.
What gases made up the early atmosphere?
Mainly carbon dioxide, with little oxygen and some nitrogen, methane, and ammonia.
How did oxygen levels increase in the atmosphere?
Photosynthesis by early plants and algae released oxygen.
How did carbon dioxide levels decrease?
Dissolved in oceans, locked in sedimentary rocks, used in photosynthesis.
