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Flashcards in C3b Deck (12)
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1
Q

What experiments can you do to follow the rate of reactions?

A
  • a rate of reaction that produces gas can be observed by measuring how quickly gas is produced:
  • measure the change in mass while the experiment is happening, mass will fall as gas is released, take readings of mass at regular time intervals
  • measure volume of gas given off in a gas syringe at regular time intervals
2
Q

What does rates of reactions depend on?

A
  • collision frequency of reacting particles (more collisions, faster reaction)
  • energy transferred during collisions (particles have to collide with enough energy for a collision to be successful)
3
Q

How the amount of product determined?

A

-depends on the amount of reactant started with
-more reactant means more particles, which will have more reactions so more product
-total amount of product is directly proportional to limiting reactant
once all the limiting reactant is used up the reaction can’t continue, even if some reactants are in excess

4
Q

How is the rate of reaction increased?

A

-by more collisions

5
Q

What does the rate of reaction depend on?

A
  • temperature
  • concentration
  • size of particles
  • prensence of catalyst
6
Q

How does concentration (pressure) affects the rate of reaction?

A
  • more concentrated solutions have more particles of a reactant in the same volume)
  • making collisions more likely
  • increasing pressure in a gas means molecules are more crowded , so frequency of collision increases
7
Q

How does temperature affects the rate of reaction?

A
  • temperature increase means particles move faster, moving quicker means more collisions
  • temperature increase, increases the energy in collisions (since particles move faster) meaning more particles will collide with enough energy to make reactions happen
8
Q

How does a catalyst affects the rate of reaction?

A
  • increases number of successful collisions
  • gives reacting particles a surface to stick to where they can collide with each other (reducing the energy needed to react before)
  • number of collisions isn’t increased, but successful collisions are
9
Q

How does the size of particles affects the rate of reaction?

A
  • breaking a solid reactant into smaller solid particles increases surface area
  • particles around it have more area to work on, so collision frequency increases
10
Q

What are limiting reactants?

A

-the reactant being totally used up

11
Q

What are reactants in excess?

A

-reactants left behind at the end of a reaction

12
Q

Why do factories making fine powders have to be careful?

A
  • fine powders of combustible materials disperse in air and burn incredibly fast because of the big surface area
  • if there’s a spark they explode (very fast reaction that releases lots of gaseous produces very quickly)