Factors Affecting the Equilibrium Reaction of Iron (III) and Thiocyanate ions
Research Question
How does the change in temperature of Iron (III) Thiocyanatoiron, containing iron (III) ions Fe3+ (aq) and thiocyanate ions SCN¬¬- (aq), affect the absorbance of the solution?
- Temperature at 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, and 60 °C (equilibrate the Iron (III) Thiocyanatoiron (aq) in various temperatures using a digital water bath, and temperature checked using a digital thermometer connected to a data logger)
- Production rate of thiocynate ion measured by the degree of change in color using a colorimeter after 600 seconds since the reactants are mixed.
- The quantitative data of the absorbance of the solution will allow the determination of the concentration of the Iron (III) Thiocyanatoiron using the Beer–Lambert Law. The difference in concentration of the solution per temperature point provides the precise effect of temperature on the reaction’s equilibrium position.
Introduction
This experiment investigates how changing a factor that affects the equilibrium reaction, in this case temperature, affects the equilibrium position.
Fe 3+ (aq) + S︎CN – (aq) ⇌ Fe ( SCN ) 2+ (aq) ( ∆H = - ve )
Pale Yellow Colorless Blood Red
This experiment uses Iron (III) ion and thiocyanate ion; the two chemicals are yellow colored and colorless, respectively. The product of the forward reaction is Iron (III) Thiocyanatoiron, which has a blood red color.
Dynamic equilibrium is when the macroscopic properties of the reaction are in constant at a specific temperature when the rate of the forward reaction is equal to that of the reverse reaction in a closed system. (Derry, Connor & Jordan, 2009)
Le Chatelier's Principle states that the change in temperature, pressure, or concentration will cause a shift in the reversible. (Derry, Connor & Jordan, 2009) Temperature, pressure, and concentration of a chemical are factors that may cause a shift in equilibrium position; the shift is to compensate the changes made by one of the three factors.
Since the forward reaction is exothermic, the increase in temperature increases the rate of the reversed reaction, meaning more Fe 3+ (aq) and S︎CN – (aq) will be formed, thus shifting the equilibrium position to the left, so the solution will be in yellow.
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-
...eases, including temperature. It is determined from the data that the reaction is more likely to have a step wise mechanism than a concerted due to the small – ΔS and a relatively large value of ΔH from the tables. Due to some errors, it is best to perform another experiment for future protocols. In addition with the variance the 35°C where at one point the absorbance levels off and then increases. In comparison to the rate constant against temperatures, at 25°C it is higher than 35 and 45. More test is required to ensure proper determination of the rate constant at those temperatures.
4. Pour hot water into one beaker and adjust the temperature to 39°C by adding colder water if needed
When there is a heat exchange between two objects, the object’s temperature will change. The rate at which this change will occur happens according to Newton’s Law of heating and cooling. This law states the rate of temperature change is directly proportional between the two objects. The data in this lab will exhibit that an object will stay in a state of temperature equilibrium, unless the object comes in contact with another object of a different temperature. Newton’s Law of Heat and Cooling can be understood by using this formula:
to an unfavorable free energy change for the process. Once added to a system, before equilibrium
However, there is no color change at end point of these reactions, so an indicator had to be added into the solutions to indicate the end point. An indicator is a chemical which is used to indicate the presence of the another substance in the solution; it changes colors when the ions H+ are added or removed by dissociation reaction. In this experiment, phenolphthalein was used as an indicator to indicate the presence of base in a solution by changing the color of the solution from colorless into pink. When the concentration of H+ is low, the solution becomes pink, and when the concentration of ions H+ is high, it becomes clear. The equivalent point is determined when there is a color change from colorless into light pink, and it is also an approximation of the end point. The concentrations were calculated by the equation M1V1 = M2V2, which means that the moles number of the base must equal to the moles number of an acid. The mole ratio in these reactions are 1:1 that means the moles’ number of the first reactant is equal to the moles’ number of the second one at the end
In a 100ml beaker 30mls of water was placed the temperature of the water was recorded. 1 teaspoon of Ammonium Nitrate was added to the water and stirred until dissolved. The temperature was then recorded again. This was to see the difference between the initial temperature and the final temperature.
• An increase in the temperature of the system will increase the rate of reaction. Again, using the Maxwell-Boltzmann distribution diagram, we can see how the temperature affects the reaction rate by seeing that an increase in temperature increases the average amount of energy of the reacting particles, thus giving more particles sufficient energy to react.
Although the experiment produced varying results amongst the pairs of test tubes in each of the water temperatures, the Mean calculations proves that the temperature rising will increase the amount of kinetic energy in the movement of the Phosphate and Lipids in the cell membrane as well as breaking the hydrogen bonds of the proteins in the cell membrane,
My aim in this piece of work is to see the effect of temperature on the rate of a reaction in a solution of hydrochloric acid containing sodium thiosulphate.
The aim of my investigation is to find out whether the increase of temperature increases the rate of reaction between the two reactants of Sodium Thiosulphate and Hydrochloric acid. I will then find out and evaluate on how temperature affects this particular reaction. Factors There are four main factors, which affect the rate of reaction that are considered as variables for the experiment I will be doing, they are the following: Molecules can only collide when two of them meet together.
Looking at the table of results above and the graph, it is shown that the higher the temperature got, the shorter the reaction time. The obtained results have been plotted on a line graph of the temperature of hydrochloric acid (y-axis) against reaction time (x-axis). This line graph in fig.2 also clearly shows that as the temperature increases, so does the speed of the reaction, shown by a reduction in the time taken. This corroborates the collision theory, where as the temperature of particles increase, the particles gain more kinetic energy and react with each other upon collision. This is shown as to happen in the hydrochloric acid, where the hydrochloric acid particles collide more with the particles of the magnesium ribbon as the temperature was increased. The above graph shows a gradual sloping curve, which gets steeper at higher temperatures. This shows that the reaction will reach a peak rate of activity as the gaps between the temperature and reaction times continue to decrease. The experiment fulfills the aim and clearly shows that as the temperature of a reaction is increased so does it’s rate of reaction, proving the hypothesis to be correct.
We took pictures of each other’s data once finished with the lab. For the paper chromatography, students began by grinding 5g of spinach along with 2g of anhydrous magnesium sulfate. Students added hexanes and acetone as specified by the lab protocols. Once, the solvent was a dark green color, we placed it in a centrifuge and transfer the liquid portion of the solution into a test tube. Throughout this portion of the experiment, students used weighting paper as a funnel poring the indicated solution as stated by the protocol, for instance pouring silica gel and sand into the column. After, we poured about 3ml of Hexanes into the column, making sure not to let the column dry. We then added, spinach extract to the column—after, we added about 1ml of hexanes. Adding hexanes caused the solution to gain a yellow colored band. We added hexanes until the yellow band reached the bottom of the column, thus began to collect all the yellow pigment into a test tube. Once the elutant become colorless, we once again placed a waste basket under it. Finally, we collected the green pigment into another test tube by a 70%/ 30% mixture and a bit of acetone. Once the two colored bands were collected, we obtained the wavelengths of each colored band using the
No matter what the third body is, if the first and second bodies are in equilibrium, the third follows that pattern. The property of temperature in this law is a crucial cause of equilibrium due to the fact that increasing or decreasing the temperature varies the energy by creating disorder when it is absorbed into the body and disperses. For this law, “[w]hat is important is that the Zeroth Law establishes that temperature is a fundamental and measurable property of matter” and “it supersede[s] the other three laws” (“What is the Zeroth Law of Thermodynamics?”). In several reactions, especially in chemical reaction, temperature plays a major role in all of it. A potential comparison is that if a person shares a room with another person and both are organized, they will organize their room to their standards. The two people compare to the two bodies that are at equilibrium and the third body achieves equilibrium with the other two. In this case, organization is the property to achieve that equilibrium. In addition, relating to the first law, the transfer of energy can have increased strength based on the temperature such as in electricity in different reactions in the light bulbs. For the second law, energy relates to entropy where temperature can increase the energy that can increase the entropy, leading to further chaos and havoc.
The aim of this investigation is to: 1) find the rate equation for the reaction between hydrogen peroxide, potassium iodide and sulphuric acid by using the iodine stop clock method and plotting graphs of 1/time against concentration for each variable. Then to find the activation energy by carrying out the experiment at different temperatures using constant amounts of each reactant and then by plotting a graph of in 1/t against I/T, 3) to deduce as much information about the mechanism as possible from the rate equation.