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.
What should you do after recording the time taken for the reaction to complete when measuring the rate of reaction?
Repeat steps 1-4 two more times at the same concentration of thiosulfate solution.
Order the steps for finding the rate of reaction: I. Place the flask over a piece of paper with a cross drawn on it. II. Record the time taken for the reaction to complete. III. Repeat steps 1-4 two more times at the same concentration. IV. Put 50 cm³ sodium thiosulfate solution into a flask. V. Add 10 cm³ dilute hydrochloric acid, swirl gently.
IV → I → V → II → III
What type of flask is used in this investigation?
A volumetric flask
Why do you repeat the reaction two more times in step 5 of the method? (Select two answers)
- You can find out if the results are reproducible.
- It makes it easier to spot anomalies.
Which variable should you record in the left-hand column of the results table?
Concentration of sodium thiosulfate solution
Which variable should you record in the right-hand column of the results table?
Time taken for the reaction to complete
What mistake has the student made in preparing the results table?
The student hasn’t included units in the column headings
At which concentration of sodium thiosulfate solution was there an anomalous result?
16 g/dm3
The anomalous result is identified at this concentration.
What type of error caused the anomaly highlighted in the table?
Systematic error
This type of error consistently affects the results in a predictable way.
In seconds, calculate the mean time taken for the reaction to complete when the concentration of sodium thiosulfate solution was 16 g/dm3.
128
This is the mean time calculated from the trials.
What type of variable is the concentration of sodium thiosulfate solution?
Continuous variable
This variable can take any value within a range.
Which variable should you plot on the x-axis of your line graph?
A concentration of sodium thiosulfate solution
Which variable should you plot on the y-axis of your line graph?
B mean time taken for the reaction to complete
Has the line of best fit been drawn correctly? Justify your answer.
D Most of the points are on or close to the line of best fit
What type of relationship is there between the two variables on the graph?
B non-linear
In g/dm3, what concentration of sodium thiosulfate solution would take 80 seconds to fully react? Don’t include the unit in your answer.
12
What is the predicted time for the reaction to complete with a concentration of sodium thiosulfate solution at 20 g/dm3?
_____
The specific predicted time should be calculated based on the graph provided.
As the concentration of sodium thiosulfate solution increased, how did the mean time taken for the reaction to complete change?
A decreased at a steady rate
This indicates that higher concentrations lead to faster reactions.
Order the statements explaining why increasing the concentration of reactants increases the rate of reaction.
II → I → III
The correct order reflects that a higher concentration results in more particles, leading to more frequent collisions, which increases the reaction rate.
True or False: A higher concentration means that there are fewer particles per unit of volume.
False
A higher concentration actually means there are more particles per unit of volume.
What leads to a higher rate of reaction when reactant concentration increases?
More frequent collisions
The increase in particle collisions is a direct result of higher concentrations.
Select the correct table that presents the same data recorded in two different ways.
_____
The answer should be selected based on the visual representation of the data.
Is temperature of the acid a continuous variable or a categoric variable?
Continuous variable
Continuous variables can take any value within a range.
Is time taken for the reaction to complete a continuous variable or a categoric variable?
Continuous variable
Continuous variables measure quantities that can be divided into finer increments.
What would be the most suitable way to present the data shown in the table?
Line graph
Line graphs are useful for showing trends over time or continuous data.
Which variable should you plot on the x-axis of your line graph?
Temperature of the acid (°C)
The independent variable is typically plotted on the x-axis.
Which variable should you plot on the y-axis of your line graph?
Time taken for the reaction to complete (s)
The dependent variable is typically plotted on the y-axis.
Which axis shows the most suitable starting value for the scale on the x-axis?
A
The starting value should be based on the range of the data being presented.
Which axis shows the most suitable starting value for the scale on the y-axis?
A
This question assesses the understanding of graph scales and appropriate starting values.
Which graph has the line of best fit correctly drawn?
B
Understanding lines of best fit is crucial for interpreting data trends in graphs.
Calculate the mean time taken for the reaction to complete (s) when temperature of the acid was 25 °C.
76
This value is derived from a set of measurements taken during the experiment.
Calculate the mean time taken for the reaction to complete (s) when temperature of the acid was 35 °C.
39
This value reflects the reaction time at a higher temperature.
At what temperature was time taken for the reaction to complete 95s?
23.0
The relationship between temperature and reaction time is key in understanding reaction kinetics.
What was the time taken for the reaction to complete (s) when the temperature was 37.0 °C?
35
Which data point doesn’t fit the pattern of the other results?
B
What type of relationship is there between the two variables on the graph?
A non-linear relationship
What conclusion can you draw from the graph?
As the temperature of the acid increased, the time taken for the reaction to complete decreased
The results in the graph support the student’s hypothesis. True or False?
True
What does the graph indicate about the student’s prediction?
The student’s prediction was correct
This implies that the experimental outcomes aligned with the student’s expectations.
Which variable could you measure to find out the rate of the reaction between hydrochloric acid and magnesium?
You could measure:
* A volume of gas collected from the reaction
* B time taken for the reaction to complete
* C mass of the products lost
* D temperature of the acid
Each of these variables can provide insight into the reaction rate.
What type of error is indicated by a thermometer reading 2 °C higher than it should?
B systematic error
Systematic errors are consistent inaccuracies that affect measurements in a predictable way.
What error has the student made in recording the results shown in the table?
B systematic error
This suggests that the error consistently affected the recording of results.
True or False: A systematic error can lead to consistent inaccuracies in measurements.
True
Systematic errors differ from random errors, which vary unpredictably.
Fill in the blank: A _____ error occurs randomly and may lead to fluctuations in measurement results.
[random error]
Random errors are typically due to unpredictable factors during measurement.
What is the mean time taken for the reaction to complete at 30 °C?
Numerical value (nearest whole number)
Specific value not provided in the text
What is the mean time taken for the reaction to complete at 40 °C?
Numerical value (nearest whole number)
Specific value not provided in the text
What type of error do you reduce the effect of by calculating a mean?
A random error
Calculating the mean helps to minimize the impact of random fluctuations in measurements.
What error has the student made in plotting the graph?
A axis did not start at zero
Other potential errors include: the plot area is too small, axis labels and units missing, or a curve drawn instead of a straight line.
What conclusion can you draw from the graph?
As the temperature of the acid increased, the time taken for the reaction to complete decreased.
This indicates that higher temperatures generally accelerate chemical reactions.
Fill in the blank: When the time taken for the reaction to complete is shorter, it means that the reaction happens at a _______ rate.
faster
A faster reaction rate implies that the reactants are converted to products more quickly.
What was the maximum value for the independent variable in this investigation?
40
This value represents the highest temperature tested in the investigation.
True or False: The results in the table support the hypothesis that temperature affects the rate of a reaction.
True
The data collected demonstrates a correlation between temperature and reaction rate.
True or False: The student’s prediction was correct.
True
This suggests that the student’s initial hypothesis aligned with the experimental results.
What conclusion can you draw from the graph?
As the temperature of the acid increased, the time taken for the reaction to complete decreased.
This indicates that higher temperatures generally accelerate chemical reactions.
Fill in the blank: When the time taken for the reaction to complete is shorter, it means that the reaction happens at a _______ rate.
faster
A faster reaction rate implies that the reactants are converted to products more quickly.
What was the maximum value for the independent variable in this investigation?
40
This value represents the highest temperature tested in the investigation.
True or False: The results in the table support the hypothesis that temperature affects the rate of a reaction.
True
The data collected demonstrates a correlation between temperature and reaction rate.
True or False: The student’s prediction was correct.
True
This suggests that the student’s initial hypothesis aligned with the experimental results.
How could you prove that the results of this investigation were repeatable?
Select two answers:
* Use a different method to carry out a similar investigation.
* Repeat the same investigation.
Which method is suitable to show that the pattern continues with different concentrations of acid?
Show that the pattern continues with different concentrations of acid.
Is the temperature of the acid a continuous variable or a categoric variable?
Continuous variable
Is the time taken for the reaction to complete a continuous variable or a categoric variable?
Continuous variable
What would be the most suitable way to present the data shown in the table?
Line graph
Fill in the blank: The same data has been recorded in _______ different ways.
two
True or False: A pie chart is the most suitable way to present the data shown in the table.
False
Which variable should you plot on the x-axis of your line graph?
Time taken for the reaction to complete (s)
The x-axis typically represents the independent variable, often time in reaction studies.
Which variable should you plot on the y-axis of your line graph?
Temperature of the acid (°C)
The y-axis usually represents the dependent variable, which is affected by the independent variable.
Which axis shows the most suitable starting value for the scale on the x-axis?
A
The starting value on the x-axis should be determined based on the data range.
Which graph has the line of best fit correctly drawn?
A
The line of best fit should represent the trend of the data points accurately.
What is the mean time taken for the reaction to complete at 25 °C?
To be calculated based on provided data
Include the same number of decimal places as other values in the table.
What is the mean time taken for the reaction to complete at 35 °C?
To be calculated based on provided data
Include the same number of decimal places as other values in the table.
At what temperature was the time taken for the reaction to complete 95s?
To be determined based on provided data
Units not required.
What was the time taken for the reaction to complete at 37 °C?
To be calculated based on provided data
Units not required.
Which data point doesn’t fit the pattern of the other results?
To be identified from the provided data
Requires analysis of the data set.
What type of relationship is there between the two variables on the graph?
A non-linear relationship
The nature of the relationship can affect the interpretation of results.
What conclusion can you draw from the graph?
As the temperature of the acid increased, the time taken for the reaction to complete decreased.
This indicates a negative correlation between temperature and reaction time.
Do the results in the graph support the student’s hypothesis?
Yes
The hypothesis is confirmed if the data aligns with the expected outcome.
Do the results in the graph support the student’s conclusion?
Yes
A conclusion is supported if it logically follows from the data presented.
