Chemistry Socrative - WARNING A MASSSIVE AMOUNT OF CARDS AND TECHNICAL DIFFICULTIES⚠️ Flashcards
What is meant by the rate of a reaction?
How fast the reactants are converted into products
The rate of a reaction quantifies the speed at which reactants are transformed into products.
Which of the following could you measure to find out the rate of a reaction? (Select all that apply)
- Volume of gas produced
- Mass of reactant used
- Time taken for the reaction to complete
Each of these measurements can provide insights into the speed of a chemical reaction.
How do you know when the reaction between magnesium and hydrochloric acid is complete?
The magnesium is no longer visible because it has all reacted
The visibility of magnesium indicates its consumption in the reaction.
Fill in the blank: At higher temperatures, the particles have more energy and are more likely to _______.
collide and react
Increased temperature enhances particle movement, leading to more frequent collisions.
What does a steep gradient on a rate of reaction graph indicate?
The fastest rate of reaction
A steep slope indicates a rapid change in the amount of product formed over time.
True or False: The hydrochloric acid changing color indicates the completion of the reaction.
False
The visibility of magnesium is a more direct indicator of the reaction’s completion.
What is the relationship between temperature and reaction rate according to the hypothesis?
The temperature of the acid affects the amount of magnesium that can react
Higher temperatures lead to increased reaction rates due to more energetic collisions.
What is a student’s hypothesis regarding the reaction between magnesium and hydrochloric acid?
Temperature affects the rate of the reaction
This hypothesis aims to determine how temperature influences the reaction rate.
Which method is most suitable to test the hypothesis about temperature affecting the reaction rate?
Change the temperature of the acid, and see how that affects the amount of gas that is released
This method directly tests the impact of temperature on the reaction.
What is the independent variable in this investigation?
Temperature of the acid
The independent variable is what is manipulated in the experiment.
What is the dependent variable in this investigation?
Time taken for the reaction to complete
The dependent variable is what is measured in response to the independent variable.
Select a logical prediction for the investigation concerning temperature and reaction time.
As the temperature of the acid increases, the time taken for the reaction to complete will decrease
This prediction reflects a common understanding of reaction rates and temperature.
True or False: Changing the strength of the acid is the best way to test the hypothesis about temperature.
False
The hypothesis specifically concerns temperature, not acid strength.
Fill in the blank: The _______ variable is the factor that is changed in the experiment.
independent
Understanding the role of independent and dependent variables is crucial in experimental design.
Fill in the blank: The _______ variable is the factor that is measured in the experiment.
dependent
The dependent variable’s changes are observed as a result of manipulating the independent variable.
What is the independent variable in the investigation?
Temperature of the acid
The independent variable is the factor that is changed in an experiment to test its effects.
What is the most suitable way to vary the temperature of the acid?
Use a water bath set to specific temperatures
A water bath allows for controlled temperature settings during experiments.
Apart from temperature of the acid, identify two variables that could affect the time taken for the reaction to complete.
- Amount of acid
- Mass of magnesium
Other variables include the concentration of the acid and surface area of magnesium.
How could you control the volume of acid in the investigation?
Use a measuring cylinder to measure a fixed volume
A measuring cylinder provides accurate volume measurements for experiments.
What volume measurement should be recorded in the investigation?
24.0
The measurement refers to the volume of acid used in the experiment.
How could you control the mass of magnesium in the investigation?
Use a mass balance
A mass balance ensures precise measurement of the magnesium’s mass for consistent results.
What are the suitable temperature values to investigate the effect of different temperatures of acid?
20, 25, 30, 35 and 40 °C
In this investigation, what is the independent variable?
Temperature of the acid
In this investigation, what is the dependent variable?
Time taken for the reaction to complete
Which variable should be recorded in the left-hand column of the table?
Time taken for the reaction to complete (s)
Which variable should be recorded in the right-hand column of the table?
Temperature of acid (°C)
Which cell contains an anomalous result?
Cell A
Fill in the blank: The independent variable is the temperature of the acid and the _______ is the time taken for the reaction to complete.
dependent variable
True or False: The volume of acid is the independent variable in this investigation.
False
List the variables that could potentially be recorded in the investigation.
- Time taken for the reaction to complete (s)
- Temperature of acid (°C)
- Volume of acid (cm3)
- Mass of magnesium (g)
- Volume of gas produced (cm3)
What should you do with an anomalous result from an investigation?
You could either:
* Use the result in the same way as the other results
* Repeat the result
* Remove the result when calculating the mean
* Change the result to fit the pattern
Anomalous results can significantly affect the outcome of an investigation and should be handled carefully.
What is the mean time taken for the reaction to complete when the temperature of the acid is 20 °C, excluding anomalous results?
121
The mean should be calculated based on valid results only.
What is a hazard in the context of an investigation?
A hazard is something that presents possible danger.
Hazards can lead to accidents or injuries if not properly managed.
Identify one hazard in the investigation.
One hazard is:
* Glassware breaking
Other examples of hazards include chemical spills and equipment malfunctions.
What is a correct risk assessment for a hazard like glassware breaking?
A risk assessment should identify the hazard, state the risk posed, and suggest control measures to prevent problems happening.
Effective risk assessments are crucial for ensuring safety in laboratory environments.
True or False: A risk assessment should only identify the hazard.
False
A risk assessment must also state the risks and suggest control measures.
Fill in the blank: A hazard could be the _______ causing severe burns at 40°C.
water bath
Water baths are common in experiments but can pose thermal hazards.
What should be done if acid splashes onto skin or into eyes?
Rinse your eye with a dilute alkali to neutralise the acid.
First aid procedures should be in place for handling chemical splashes.
What is the appropriate action for cleaning up broken glass?
Use a brush and dustpan to sweep up any broken glass and place it in the glass bin.
Proper disposal of broken glass is important to prevent injuries.
What two things are required for a chemical reaction to take place?
The particles of the reactants must collide with each other and the particles must collide with enough energy.
Both conditions are essential for effective collisions that lead to a reaction.
The rate of reaction is defined as what?
The time it takes for the reactants to be used or for the products to be formed.
This definition highlights the duration of the reaction process.
How can the rate of a chemical reaction be measured?
By measuring how quickly a reactant is used up or a product forms.
This measurement provides insight into the speed of the reaction.
If a chemical reaction completes in a short amount of time, the rate of the reaction is—
high.
A high rate indicates a fast reaction, while a low rate indicates a slow reaction.
What happens when the concentration of a reactant changes?
The number of collisions between the reactant particles changes
This is because a higher concentration results in more particles in a given volume, leading to increased collision frequency.
What is the independent variable in this investigation?
Concentration of hydrochloric acid
The independent variable is what the experimenter changes to see its effect on the dependent variable.
What is the dependent variable in the investigation?
Time taken for the reaction to complete (the cross to no longer be visible)
The dependent variable is what is measured in the experiment, which is affected by changes in the independent variable.
List three variables that should be controlled in this investigation.
- Concentration of hydrochloric acid
- Volume of sodium thiosulfate solution
- Initial temperature of the reactants
Controlling these variables ensures that the results are due to the changes in the independent variable alone.
What happens when sodium thiosulfate and hydrochloric acid react together?
The solution goes cloudy
This cloudiness is due to the formation of sulfur as a product of the reaction.
Which product of the reaction causes the cloudiness when sodium thiosulfate reacts with hydrochloric acid?
Sulfur
The reaction produces sulfur, which causes the solution to appear cloudy.
What is the end point of the reaction between sodium thiosulfate and hydrochloric acid?
The point at which the cross is no longer visible
This indicates that the reaction has completed.
Fill in the blank: The first step in finding the rate of reaction at each concentration of sodium thiosulfate solution is to _______.
Place the flask over a piece of paper with a cross drawn on it
What is the second step in finding the rate of reaction with sodium thiosulfate?
Add 10 cm³ dilute hydrochloric acid, swirl gently, and then record the time taken for the reaction to complete.