Rates of Reactions Flashcards
(34 cards)
What is the rate of a chemical reaction?
How fast the reactants are changed into products.
Give an example of a slow reaction.
Rusting of iron.
Give an example of a moderate-speed reaction.
Magnesium reacting with acid.
Give an example of a fast reaction.
Burning
Give an example of a very fast reaction.
An explosion.
What does a steep line on a reaction graph show?
A fast reaction.
What does a flat line on a reaction graph show?
The reaction has finished — it’s the end-point.
How do graphs show that reactions produce the same amount of product?
They level off at the same height.
What does a steeper line that levels off at the same point mean?
A faster reaction that produces the same amount of product.
What does a graph that levels off higher mean?
More product has been formed — more reactants were used.
What must particles do for a reaction to occur?
Collide
What does the rate of a chemical reaction depend on?
How often particles collide.
What increases the rate of reaction?
More frequent collisions or a greater proportion of particles colliding.
What are the four main factors that affect the rate of reaction?
Temperature, concentration, surface area, catalyst.
How does increasing temperature affect rate of reaction?
Particles move faster and collide more frequently.
How does increasing concentration affect rate of reaction?
More particles in the same volume = more frequent collisions.
How does increasing surface area affect rate of reaction?
Smaller pieces = greater surface area = more collisions.
What is a catalyst?
A substance that speeds up a reaction without being used up.
Why is a catalyst not part of the overall chemical equation?
Because it is not used up or chemically changed.
What is the formula for rate of reaction?
Rate = quantity ÷ time.
What are the three main ways to measure rate of reaction?
Precipitation/colour change, change in mass, volume of gas given off.
What kind of reaction is measured using precipitation and colour change?
One where a visible product forms or a coloured substance disappears.
What kind of reaction is measured using change in mass?
One that produces a gas.
Why does the mass drop during a reaction measured by mass?
Gas is released and escapes.
