Reaction Rates Flashcards
Rate of reaction
It’s found by measuring quantity of reactant used/product formed over time + its speed of reaction
Factors affecting the rate of a reaction
Concentrations of reactants in solution, pressure of reacting gases, surface area of solid reactants, temperature + presence of catalysts
Factors affecting the rate of a reaction
Concentrations of reactants in solution, pressure of reacting gases, surface area of solid reactants, temperature + presence of catalysts.
Concentration
How many particles are in given volume, increasing concentration increases rate of reaction + vice versa, this is because there are more particles in same volume, which means that particles are more likely to collide + there are more frequent collision + , therefore, they’re more likely to react, increasing rate of reaction
Concentration
How many particles are in given volume, increasing concentration increases rate of reaction + vice versa, this is because there are more particles in same volume, which means that particles are more likely to collide + there are more frequent collision + , therefore, they’re more likely to react, increasing rate of reaction
Pressure
Increasing pressure of gaseous reactants increases rate of reaction + vice versa, this is because space in which gas particles are moving in becomes smaller, so they become closer together, increasing frequency of collisions + chance of them colliding, which means that particles are more likely to react, increasing rate of reaction
Surface Area
Increasing surface area of solid reactants increases rate of reaction as there’s increased area for reactant particles to collide with, smaller pieces of solid, larger surface area, which means more frequent collisions + greater chance of reaction, increasing rate of reaction
Temperature
Increasing temperature increases rate of reaction + vice versa, this is because particles have more energy, which means that they move faster + are more likely to collide with other particles, so when particles collide, they do so with more energy +, therefore, frequency of successful collisions increases + there’s greater chance of reaction, increasing rate of reaction
Temperature
Increasing temperature increases rate of reaction + vice versa, this is because particles have more energy, which means that they move faster + are more likely to collide with other particles, so when particles collide, they do so with more energy +, therefore, frequency of successful collisions increases + more , increasing rate of reaction
Catalysts
Using catalysts speeds up reaction as it provides alternative route for reaction with lower activation energy, which increases rate of reaction, they change rate of chemical reactions but aren’t used up during it, so only small amount is needed to catalyse large amounts of reactants, different reactions need different catalysts, enzymes act as catalysts in biological system
Activation Energy
It’s minimum amount of energy that particles need to start reaction, if particles collide with less energy than activation energy, then they won’t react + will just bounce off each other
Collision Theory
For chemical reaction to take place, particles of different substances must collide with sufficient energy, more collisions between particles in given time, faster reaction
Everyday catalysts
Nickel: catalyst in production of margarine, Iron: catalyst of production of ammonia from nitrogen + hydrogen
Catalytic converters in cars
It’s device that’s fitted to exhaust pipe of car to clean up exhaust fumes, catalyst is platinum, it catalyses conversion of carbon monoxide + nitrogen oxide into less polluting carbon dioxide + nitrogen, they have high surface area to increases rate of reaction, they work best at high temperatures
