rate and extent of chemical change Flashcards
What does a flat line on a rate of reaction graph indicate?
That the reaction has stopped
What are examples of fast and slow reactions?
Fast-explosions
moderate-magnesium reacting with acid
slow-rust
What factors does rate of reaction depend on?
temperature, concentration of a solution, pressure of a gas, surface area, presence of a catalyst
What is collision theory?
the rate of a chemical reaction depends upon the frequency of collisions and the energy transferred during a collision
How does increasing temperature increase rate of reaction?
When temperature is increased, particles move more quickly and thus collide more frequently and with a greater energy, making collisions more successful
How does increasing concentration or pressure increase rate of reaction?
more particles occupy a smaller space making collisions more frequent
How does increasing surface area increase rate of reaction?
breaking up a solid reactant into smaller pieces increases surface area to volume ratio so the particles have more area to work on and collide more frequently
How does using a catalyst increase rate of reaction?
They decrease the activation energy by providing an alternative reaction pathway with lower activation energy
What is the formula for rate of reaction?
amount of reactant used/time or
amount of product formed/time
How to do the precipitation and colour change required practical?
use a solution that is initially transparent and the product is a precipitate that clouds the solution. Draw a cross underneath your beaker and mix your reactants. Use a stopwatch to observe how much time it takes for the cross to disappear
What are the problems with the precipitation and colour change required practical?
It is subjective and a rate of reaction graph cannot be plotted from the results
