Our most basic knowledge of chemical equilibria comes from a French man named Henry-Louis Le Chatelier. Through his studies of equlibria and the effects of changes provoked on these equilibria, he was able to come up with a principle that is studied widely today. Le Chatelier’s Principle, which was named after him, states that a change in one of the variables in a system at equilibrium will cause a shift in the position of the equilibrium that counteracts this system. Le Chatelier’s Principle is aimed at three changes that can cause a disruption in a system at equilibrium. These three changes include a change in the temperature of a reaction, a change in the concentration of one of the variable of a reaction, and a change in the pressure on a system. [1] As stated in Le Chatelier’s Principle, a change in the concentration of one variable in a reaction will cause the other variables to shift. If a product were added to a system, the system would shift towards the reactants to reach equilibrium again. If a reactant were added to a system, the system would shift towards the products to reach equilibrium again. If a product were removed from a system, the system would shift towards the products. If a reactant were removed from a system, the system would shift towards the reactants. Take the following example: A+2B⇌C+D. If you were to increase the concentration of A or 2B, the system would shift right to increase the concentrations of C and D. If you were to increases the concentration of C or D, the system would shift left to increase the concentration of A or 2B. [2] A change in the pressure of a system will only have an effect if the system is made up of gases. If the pressure of a system of gases were to increase, there will be a... ... middle of paper ... ...ibrium shares the same definition as chemical equilibrium. They both occur whenever the rates of the forward and reverse reactions are equal to each other. The common ion effect is the idea that if a reaction ever falls out of equilibrium, a shift will occur to re-balance it again. The addition of a common ion to the weak side of an equilibrium will result in a shift towards the right side of the reaction, which are the reactants and the weak parts of the equilibrium. [5] The chemical equation associated with chemical equilibrium that we will be using in this lab is CuCl42-(aq) + 4H2O (l) ⇌ Cu(H2O)42+ + 4Cl-(aq). My hypothesis for this experiment is that the heat study tube will turn blue, the cooling study tube will turn green, the dehydration study tube will turn blue, the hydration study tube will turn green, and the common ion effect study tube will turn blue.
For example, a balanced chemical equation of a certain reaction specifies that an equal number of moles of two substances A and B is required. If there are more moles of B than of A, then A is the limiting reactant because it is completely consumed when the reaction stops and there is an excess of B left over. Increasing the amount of A until there are more moles of A than of B, however, will cause B to become the limiting reactant because the complete consumption of B, not A, forces the reaction to cease. Purpose
Felder, M. Richard, Elementary Principles of Chemical Processes, 3rd ed.; Wiley: New Jersey, 2000; p 631.
The purpose of this lab was to to cycle solid copper through a series of chemical forms and return it to its original form. A specific quantity of copper undergo many types of reactions and went through its whole cycle, then returned to its solid copper to be weighted. We observed 5 chemical reactions involving copper which are: Redox reaction (which includes all chemical reactions in which atoms have their oxidation state changed), double displacement reaction, precipitation reaction, decomposition reaction, and single displacement reaction.
== == I completed a table to show my results, here is the table: Table 1. Results of different changes of substances Part A Copper (II) Sulfate and Water Reactant description Water (reactant): Color: Colorless Transparency:
5. In a gas increasing the pressure means molecules are more squashed up together, so there will be more collisions. My Investigation. I am going to investigate the concentration variable. I have chosen this because in my opinion it will be the easiest one to measure.
The task of this lab is to create and analyze hypotheses of the different relationships between the properties of gasses. These properties include temperature, pressure and volume. The ideal gas law is the source for many of these hypotheses and are tested through the various known laws of gasses. Such laws include Lusaacs Law, Charles Law and Boyles Law. The data, gathered from the results of the experiments mentioned above, was then graphed to show the relationship between the properties that gasses inhibit. The data provided was also utilized to derive a proportionality constant, k. Pressure rises when temperature rises, pressure rises when volume falls and volume rises when temperature rises. All of these outcomes were observed during the
With regard to temperature, the reaction moving to the right is exothermic i.e. it gives off energy (in the form of heat). Therefore reference to Le Chatlier's Principle shows that the reaction to the right is favoured by low temperatures.
(e) There is no change in equilibrium when an inert gas (noble gas, therefore outer valence shell is full, making the molecule very stable) is added to the reaction without changing the volume, since the amount of reactants and products does not change.
Co(H2O)6 2+/ CoCl4 2- Equilibrium Demonstration Sheet. (n.d.). Co(H2O)6 2+/ CoCl4 2- Equilibrium Demonstration Sheet. Retrieved November 20, 2013, from http://chemed.chem.purdue.edu/demos/demosheets/12.10.html
By balancing the two polyatomic ions the rest of the ions are balanced as well. Again, this is often the case but not always.
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.
To control the rates of chemical reactions is imperative to the continued existence of our species. Controlled chemical reactions allow us to move forward in society, constantly. We find new ways to provide light and heat our homes, cook our food, and pursue in crafts that benefit our society. There are, however, just as there are advantages, disadvantages to the efficiency of controlling the rate of reactions, which in some cases can be fatal to our scientific development and progression. The growth of humankind necessitates that we must be able to control the rate of chemical reactions.
In the second half of the experiment, temperature and pressure were revealed to have a directly proportional relationship (DQ 5). This relationship is modeled by k=P/T, where P is pressure, T is temperature, and k is a constant in kPa/K (Table 2) (DQ 5, 6).
Thermodynamics deals with systems in equilibrium; it may be used to foresee the amount of energy required to change a system from one equilibrium state
The amounts of various substances liberated by a given quantity of electricity are inversely proportional to their chemical equivalent weights.