Science Chemistry Flashcards
(30 cards)
What is the rate of a chemical reaction?
The rate of a chemical reaction tells us how quickly a product is formed or how quickly a reactant is used up.
What must happen for a chemical reaction to occur?
The reactant particles must collide with enough energy.
What are successful collisions?
Those collisions that produce a chemical reaction are called successful collisions.
How is the mean rate of reaction calculated?
mean rate of reaction = quantity of reactant used / time taken
mean rate of reaction = quantity of product formed / time taken
How can the mass of a reaction mixture be measured?
The changing mass of a reaction mixture can be measured during a reaction, particularly useful when gases are given off.
What happens to the mass of a reaction mixture when gas escapes?
The mass of the reaction mixture decreases.
What equipment can be used to collect gas during a reaction?
Gas can be collected using a gas syringe, measuring cylinder, or upside-down burette.
What factors affect the rate of a chemical reaction?
Factors include concentration and pressure, catalyst, surface area, and temperature.
How does a catalyst affect a chemical reaction?
A catalyst speeds up a chemical reaction without getting used up and offers an alternative pathway at a lower activation energy.
What are biological catalysts called?
Biological catalysts are called enzymes.
What happens to the frequency of collisions when a catalyst is used?
The frequency of collisions is unchanged, but more particles are able to react.
What effect does increased concentration or pressure have on the rate of reaction?
If the number of reactant particles in a given space is doubled, there will be more frequent successful collisions, increasing the rate of reaction.
What do the lines on a rate of reaction graph represent?
The red line represents a fast reaction and the blue line a slow reaction.
What does a steep line on a reaction graph indicate?
A steep line indicates a fast reaction.
What is the significance of the plateau on a reaction graph?
The fast reaction finishes before the slow reaction as the line plateaus sooner.
What is a Catalyst
It is a substance that increases rate of reaction without being used up
What happens to reactant particles when the temperature of the reaction mixture is increased?
Reactant particles gain kinetic energy and move much more quickly, resulting in more frequent successful collisions.
How does increasing the surface area of a solid affect the rate of reaction?
Increasing the surface area exposes a larger area of the solid to other reactant particles, increasing the frequency of successful collisions.
What does a steeper gradient on a reaction graph indicate?
A steeper gradient indicates a faster reaction.
How can you calculate the rate of reaction at a specific time period on a graph?
By drawing construction lines on the straightest part of the graph and measuring the values of x and y.
What is the formula to calculate gradient in the context of reaction rates?
gradient = Y
If the rate of reaction at 20 seconds is calculated as 2.7cm³, what is the total amount of product at that time?
54 + 20 = 2.7cm³
What is the rate of reaction at 40 seconds if the amount of product is 52?
52 ÷ 40 = 1.3cm³
Fill in the blank: Large lumps of a solid have a small _______ to volume ratio.
surface area
