The controlled variable
How it will be controlled
Why it should be controlled
The size of the magnesium ribbon.
You can make sure to keep the size of the magnesium ribbon constant throughout the experiment by measuring it accurately with the help of a ruler. Make sure that the length of the magnesium ribbon is 2 cm throughout the experiment.
It is essential to keep the length of the magnesium ribbon constant throughout the experiment as it one of the 2 reactants taking part in the reaction. If were to increase or decrease the length at a random stage and fail to keep it the same during the trials, than we will not be able to collect reliable and accurate results and it won't be a fair tests
Equipment for example; use the same test tube throughout
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The reason being change in volume would also cause a change in the pressure inside the container for the same amount of gas. It would be better if you were to use a small test tube rather than large one because a large test tube will require more time for there to be an increase in the pressure
The volume of hydrochloric acid used.
This is very important as changing the volume can have a negative effect on your experiment and report. Make sure that you use 10cm3 of hydrochloric acid throughout all the 5 trials, You can measure the volume with help of a measuring cylinder or you can also use a pipette to measure it accurately
There are 2 main reasons as to why you should keep the volume of HCL constant throughout the trials/experiment. First reason being is to conduct a fair test and collect accurate and reliable results. The seconds is because if were to randomly increase the volume of hcl during our experiment, it would result in an increase in the amount of hydrogen (H) and chlorine atoms as well. This will then cause an increase in the rate of reaction.
Initial Temperature of reactants. (ambient)
It is not pragmatic to control the temperature, But you can control the temperature of reacting by conducting the experiment in room temperature which generally taken as 20 degrees
Furthermore, using a graduated cylinder with markings below the 100 mL line would have allowed for more accurate measurements of the initial volume of air in the graduated cylinder.
this is the best volume to use as it is about ¾ of a test tube full,
Apparatus: * 1 measuring cylinder * 1 test tube * 1 stop clock * A large gelatine cube containing indicator and NaOH * Hydrochloric acid ranging from 1-3 molars * A scalpel Diagram: Method: * Take the large gelatine cube and cut into 15 equal pieces * Place on piece of the cube into the test tube * Measure out 10mls of HCl in the measuring cylinder * Pour the HCl into the test tube with the gelatine cube and start the clock * Time how long it takes for the pink colour inside the gelatine cube to completely disappear * You will also notice that the cube dissolves slightly * Record your results and repeat this same process 3 times for each molar of acid: § 1 molar § 1.5 molar § 2 molar
Other methods available consisted of timing how long it took for the magnesium to disappear. We would place the liquid and the magnesium in a flask and start the timer, one reason we chose not do this is we won’t precisely know when the reaction is finished. Plus people might have different opinions of when the magnesium has disappeared. Another is timing how long it takes for a solution to turn cloudy. We would again place the liquid and the magnesium in a flask and start our timer, the reason...
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.
Input variables In this experiment there are two main factors that can affect the rate of the reaction. These key factors can change the rate of the reaction by either increasing it or decreasing it. These were considered and controlled so that they did not disrupt the success of the experiment. Temperature-
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
2. Clean the surface of a 20 cm strip of magnesium ribbon using steel wool
the chances of collisions increase thus giving a faster rate of reaction. Then the s Apparatus:. Beaker Hydrochloric acid Distilled water Measuring cylinder Pipette Test tubes Test tube rack Diagram:.. [ IMAGE] Method: The.. Measure out 10cm3 of hydrochloric acid, as the concentration requires. for each concentration its composition is.
3 cm of magnesium ribbon generally has a mass of 0.04 g and yields 40 cm3 of hydrogen when reacted with excess acid. 50 cm3 of 1M hydrochloric in this experiment is in excess.
35, 40, 45, 50, 55, 60, 65, 70, 75 and 80 beads. The experiment was
Firstly, we need to keep the chemical at a constant concentration. So, in this experiment we have chosen to keep hydrochloric acid at a constant concentration (5cm3). We could have, however, used Sodium Thiosulphate as a constant, but we had chosen to use Hydrochloric acid. Next, we must make sure that the solution is kept at a constant volume throughout the experiment. If the volume is different, then it could give different results if it was at a constant volume.
second test tube also add 6 mL of 0.1M HCl. Make a solution of 0.165