module 6 Flashcards
(12 cards)
What is rates of chemical reaction?
How fast reactants are changed into products.
What are slow reactions?
Rusting of iron, chemical weathering.
What is a moderate speed reaction?
Magnesium reacting with an acid to produce a gentle stream of bubbles.
What is an example of a fast reaction?
Burning, explosions are even faster and release a lot of gas. Explosive reactions are all over in a fraction of a second.
How can you find a speed of a reaction?
Recording amount of product formed or amount of reactant used up over time. Steeper the line on graph faster rate of reaction. Over time line becomes less steep as reactants are used up. Quickest reactions have steepest lines and become flat in least time. (revision guide).
What is the collision theory and what does the ate of chemical reactions depend on?
Collisions frequency of reacting particles. More collisions there are faster reaction is. Energy transferred during a collision. Particles have to collide with enough energy for collisions to be successful.
How do particles affect the activation energy?
Minimum amount of energy particles need to react is called activation energy. Particles need this much energy to break bonds in reactants and start reaction
How do the number of collisions affect the rates of reaction?
Factors that increase number of collisions or amount of energy particles collide with will increase rate of reaction.
How does increasing the temperature increase the rate of reaction?
When temperature increased particles moved faster, if moving faster more collisions. Faster move more energy they have, more of collisions will have energy ti make reaction happen.
How does increasing concentration or pressure increase rate of reaction?
If solution made more concentrated, means more particles knocking about in same volume of water(or other solvent). When pressure of gas increased, means same number of particles occupies a smaller space. Makes collisions between reactant particles more frequent.
How does increasing the surface area increase rate of reaction?
If 1 of reactants is solid, breaking it up into smaller pieces will increase its surface area to volume ratio. Means for same volume of solid, particles around it will have more area to work on-will be more collisions more frequently.
How do catalysts increase rate of reaction.
Catalyst is substance that speeds up reaction, without being used up in reaction itself. Means isn’t part of overall equation. Different catalysts are needed for different reactions, nut all work by decreasing activation energy needed for reaction to occur. Do by providing alternative reaction pathway with lower activation energy. Enzymes are biological catalysts-reactions in living things.
