C6 Ai Flashcards
What is the rate of a reaction?
The speed of a reaction.
How can graphs represent the rate of a reaction?
Graphs can show how the rate (speed) of a reaction changes.
What does a steeper line on a graph indicate about the rate of reaction?
The faster the rate of reaction.
What happens to the line on a graph over time as reactants are used up?
The line becomes less steep.
What can cause changes in the rate of reaction?
Changes in conditions.
Fill in the blank: The minimum amount of energy needed for particles to react is called _______.
activation energy.
What is collision theory?
An idea that explains reaction rates based on particle collisions.
How does increasing the temperature affect the rate of reaction?
Particles move faster and collide more often.
What is meant by ‘collision frequency’?
How often particles collide.
What happens to the rate of reaction if the reactant particles collide with enough energy twice as often?
The reaction will happen twice as fast.
What is the effect of increasing concentration on the rate of reaction?
More particles result in more collisions.
True or False: All reactions produce the same amount of product regardless of the time taken.
True.
What does a flat line on a reaction graph represent?
No reactants are left.
What is the relationship between the size of reactant pieces and the rate of reaction?
Smaller pieces have a larger surface area, leading to faster reactions.
What is the effect of temperature on the rate of reaction?
Increasing temperature speeds up particle movement, leading to more frequent collisions.
Higher temperatures typically result in faster reactions due to increased kinetic energy of particles.
What factors affect the rate of reaction?
The four main factors are:
* Temperature
* Concentration of a solution (or pressure of a gas)
* Surface area of a solid
* Use of a catalyst
Each factor influences how often particles collide and the energy involved in those collisions.
How does increasing the concentration of a solution affect the rate of reaction?
Higher concentration increases the number of particles in a given volume, leading to more frequent collisions.
This results in a faster reaction rate.
What is the significance of surface area in chemical reactions?
Breaking a solid reactant into smaller pieces increases its surface area, allowing more collisions with other reactants.
A larger surface area to volume ratio enhances the reaction rate.
What is a catalyst?
A catalyst is a substance that speeds up a reaction without being consumed in the process.
Catalysts provide an alternative pathway with lower activation energy.
What is the role of enzymes in chemical reactions?
Enzymes are biological catalysts that facilitate reactions in living organisms.
They are specific to certain reactions and are not consumed in the reaction.
Define ‘collision frequency’.
Collision frequency refers to how often particles collide with sufficient energy to react.
Higher collision frequency typically leads to a faster reaction rate.
Fill in the blank: A catalyst provides a different pathway for a reaction with lower _______.
activation energy.
This allows the reaction to occur more easily and quickly.
True or False: The rate of reaction will double if the collision frequency doubles.
True.
Doubling the collision frequency implies more reactions occur in the same time frame.
What happens when magnesium ribbon is powdered for a reaction with hydrochloric acid?
The powdered magnesium will react faster than the ribbon due to increased surface area.
This allows for more frequent collisions with acid particles.
How does breaking a solid reactant into smaller pieces influence the reaction rate?
It increases the surface area available for collisions, leading to a faster reaction rate.
Larger pieces have a smaller surface area compared to smaller pieces.
What is the first step in measuring rates of reaction?
Measure out a set volume of dilute hydrochloric acid using a measuring cylinder.
What should be done immediately after adding marble chips to the flask?
Quickly attach a delivery tube and gas syringe to the flask.
How often should readings of the gas volume be taken during the experiment?
At regular intervals (e.g., every 10 seconds).
What is the significance of the volume of gas produced in a reaction?
The more gas given off in a set amount of time, the faster the reaction.
Fill in the blank: To ensure accurate results, all variables except for _____ should be kept the same.
the concentration of acid
What visual indicator can be used to observe the reaction rate in a reaction involving sodium thiosulfate and hydrochloric acid?
The disappearance of a black cross.
True or False: The gas syringe provides an accurate measurement of gas volume.
True
What happens to the mass of the reaction mixture as gas is produced and escapes?
The mass of the reaction mixture falls.
What does a quicker drop in mass reading indicate?
A faster reaction.
What should be done when repeating the reaction with different concentrations of hydrochloric acid?
Control all other variables.
What is a potential safety concern when using a mass balance to measure gas production?
It releases gas into the room, which may be toxic.
What should you do to visualize the reaction when sodium thiosulfate is mixed with hydrochloric acid?
Place the flask on a piece of paper with a black cross.
Fill in the blank: The higher the concentration of acid, the _____ time it takes for the reaction.
less
Name one piece of equipment you could use to measure the volume of gas given off in a reaction.
Gas syringe
What is the purpose of the delivery tube in the experiment?
To channel gas produced into the gas syringe.
What is the outcome of the reaction between sodium thiosulfate and hydrochloric acid?
Formation of a yellow precipitate.
What gas is released during the reaction?
Sulfur dioxide
Where should the experiment involving sulfur dioxide be conducted?
In a well-ventilated place
What is the effect of increasing the concentration of hydrochloric acid (HCl) on the reaction time?
The higher the concentration, the faster the reaction
Fill in the blank: The concentration of HCl (g/dm3) used in the experiment were 18, 36, 54, and _______.
72
What was the time taken for the mark to disappear at a concentration of 36 g/dm3?
184 seconds
List two factors that should be kept constant in the experiment.
- Temperature
- Surface area of magnesium
True or False: The experiment can be conducted without safety goggles.
False
What should be worn during the experiment for safety?
Safety goggles and lab coat
What is the relationship between concentration and time taken for the mark to disappear?
Inverse relationship
In the experiment, what does a faster reaction time indicate?
Higher concentration of HCl
Fill in the blank: Different concentrations of acid affect the _______ of the reaction.
Rate
What is the term used to describe the size of the particles in a reaction?
Surface area
What does the term ‘measuring rates’ refer to in the context of this experiment?
Determining how quickly a reaction occurs
