Through the completion of this experiment, the dynamics of stoichiometry are demonstrated by preforming a chemical reaction in a solution. This procedure will ultimately show how limiting reactants are factored into a reaction by using a varying amount of reactants involved. To better understand this concept, it is vital to define stoichiometry; stoichiometry is a way of documenting the amounts of products and reactants involved through a series of coefficients that describes the ration in which the reactants will fuse together and the products form. In this particular lab, the following formula will be used to preform the necessary calculations: 〖CaCl〗_2(aq) +〖2NaOH〗_((aq) )→ 〖Ca(OH)〗_2(s) +〖2NaCl〗_((aq)) This formula states that two moles …show more content…
of NaOH must react with one mole of CaCl2 in order to form one mole of Ca(OH)2 and two moles of NaCl. In some cases, the reactants will not react completely due to uneven proportions and one will dictate the amount of product formed, known as the limiting reactant. To better understand this on a non-chemical level, one can look at cars assembled in a factory. If the worker knows that he or she must put four tires on one car body and that individual is provided with fifty (50) car bodies and one hundred and sixty (160) tires, a problem arises. Since the worker only has enough for forty (40) completed cars, the worker can make an inference that the tires are the limiting reactant, also known as a limiting reagent, and the car bodies are the excess reagent. Due to the fact that a total of forty cars can be produced from the given reactants, there will be ten car bodies left in excess. While this is a very primitive concept, it still is a great example to demonstrate the basic concepts of reactions and limiting reagents.
In relation to chemical reactions, one can take the amounts of each reactant used and use the mole to mole ratios to convert the moles of each reactant to the maximum amount of product formed, known as theoretical yield. When comparing the two values for the amount of product formed, the smaller amount formed will be the limiting reactant. This amount of the product based on the values obtained finding the limiting reactant will be the total amount of product that can be formed in the reaction. Any remaining reactant will be known as the excess reactant and this excess amount can be calculated simply by taking the total amount of the reactant used and subtracting this value from the amount of reactant to begin …show more content…
with. In this specific reaction, various amounts of CaCl2 will be added to a fixed amount of NaOH in order to determine the maximum amount of product that can be formed when mixing the two reactants. After this reaction, a white, solid precipitate of Ca(OH)2 will form along with liquid NaCl. As more and more of the CaCl2 is added to the fixed amount of NaOH, the amount of product that will be formed will eventually level off and each reaction will produce the same amount of product despite the varying amounts of CaCl2 due to limiting reactants. This can be shown graphically by plotting the CaCl2 in relation to the product formed and looking where the graph flattens out. When conducting this experiment, these reactions will be passed through filter paper to obtain the precipitates. These precipitates will then be dried and weighed to obtain the amount formed, and any excess NaCl and reactants used will be set aside until later. In order to determine the limiting reactant, theoretical yield, percent yield, and other aspects of each reaction preformed, one must determine the moles of each reaction present in the reaction. To do this, the following reaction can be used: Moles=(Volume in Liters)(Molarity) After using this formula, the individual conducting the lab can take each value for the moles and convert the number of moles of each reactant to the number of moles of product that the reactant can form when the reactants come together completely. Then, in order to find the theoretical yield, one would take the smaller of the two values of product formed and multiply that number by the molar mass of the product to obtain the mass, in grams, formed from the reaction. In order to calculate the percent yield, one would take the actual yield into account and find what percent of the reactants actually combined to form product. This can be obtained using these two formulas: Theoretical Yeild=(Moles of Product)(Molar Mass of Product) Percent Yeild= (Actual Yeild)/(Theoretical Yeild)*100 As mentioned before, the NaCl formed form the reaction and the remaining reactants will be discarded until later in the lab in order to help identify the excess reagent.
This can be accomplished by dividing the aqueous solution left over from each reaction into two equal parts. One sample will be tested with the NaOH and one will be tested with the CaCl2; by doing this one can infer which reactant is in excess. If one of the reactants is added and no additional precipitate forms, one can infer that that reactant is in excess because all that is happening is more is being added. If a precipitate forms, that reagent reacted with the excess of the other reactant and is nor in excess. If no precipitate forms for either reagent, neither ion is present during
testing.
The purpose of this experiment was to examine how the stoichiometry, “the quantitative relationships between substances involved in a chemical reaction”, can be applied to determine the quantity of sodium hypochlorite found in a bleach product. This experiment allowed it to determine how much oxidizing agent is in a cleaner by using a redox reaction, which is a reaction involving the transfer of electrons from the compound being oxidized to the compound being reduced. To determine the amount of oxidizing agent, it is necessary to accurately measure out known amounts of redox reactants, know the stoichiometry
For this experiment we have to use physical methods to separate the reaction mixture from the liquid. The physical methods that were used are filtration and evaporation. Filtration is the separation of a solid from a liquid by passing the liquid through a porous material, such as filter paper. Evaporation is when you place the residue and the damp filter paper into a drying oven to draw moisture from it by heating it and leaving only the dry solid portion behind (Lab Guide pg. 33.).
The limiting reactant of a chemical reaction is the substance that places an upper bound on the amount of product that the reaction can produce. The limiting reactant places this upper bound because the reaction must stop once all of the limiting reactant is consumed.
For this experiment, you will add the measured amount of the first sample to the measured amount of the second sample into its respectively labeled test tube then observe if a reaction occurs. In your Data Table, record the samples added to each test tube, describe the reaction observed, if any, and whether or not a chemical reaction took place.
This graph shows that as enzyme concentration increases absorption also increases. In this case absorbance can be used to measure the enzyme’s activity, the higher the absorption the higher the activity. Since absorption increases as enzyme concentration increases, enzyme activity is promoted by increased enzyme concentrations. After a certain point enzyme activity would fail to increase as a result of increased enzyme concentration since there wouldn’t be enough substrate for all of the enzymes to react with.
According to the graph on amylase activity at various enzyme concentration (graph 1), the increase of enzyme dilution results in a slower decrease of amylose percentage. Looking at the graph, the amylose percentage decreases at a fast rate with the undiluted enzyme. However, the enzyme dilution with a concentration of 1:3 decreased at a slow rate over time. Additionally, the higher the enzyme dilution, the higher the amylose percentage. For example, in the graph it can be seen that the enzyme dilution with a 1:9 concentration increased over time. However, there is a drastic increase after four minutes, but this is most likely a result of the error that was encountered during the experiment. The undiluted enzyme and the enzyme dilution had a low amylose percentage because there was high enzyme activity. Also, there was an increase in amylose percentage with the enzyme dilution with a 1: 9 concentrations because there was low enzyme activity.
The purpose of lab 1.1 Heating Baking Soda is to observe the baking soda as it is heated, the test tube, and the apparatus. Then to determine what happens to baking soda when it is heated. There are three parts to the experiment the empty test tube test, the heating baking soda test, and the tea test. To determine the effect of heating baking soda heated baking soda is compared to two different controls to isolate the properties of baking soda when it is heated. Then to determine that baking soda causes gas to be produced when heated
In the lab the reaction that took place was a synthesis reaction. A synthesis reaction, is a type of chemical reaction in which two or more simple substances combine to form a new product. The reactants may be elements or compounds. In this case it is a gas and a metal that will react and produce a compound. The general form of a synthesis reaction is, A + B → AB. In order for this lab to be done successful you need knowledge on, percent composition, the empirical and molecular formula, the law of conservation of mass, moles and molar mass, qualitative and quantitative. To begin, the percent composition of a compound is the percent of the total mass that each element has in that compound. Every compound would have a certain percent composition. To calculate percent composition of a compound, you would have to determine the total molecular mass of the compound. For example, for H2O the total molar mass would be 18.00g/mol. You would then input the mass of one of the elements and the molar pass into the equation % by weight (mass) of element = (total mass of element present ÷ total mass of compound) x 100 to find out the percent composition. So for Oxygen it would be, % of O = (16.00g ÷ 18.00g/mol) x 100 which would equal 88.9%. Therefore the percent composition of O in this compound is roughly 88.9%. Furthermore, the molecular formula is the number and types of atoms that are existing in a single molecule of a substance. The empirical formula also known as the simplest formula is the ratio of elements present in the compound. The key difference between these two is that the empirical formula shows the simplest positive integer ratio of atoms of each element present in a compound whereas the molecular formula of a compound is a way ...
A balanced chemical equation has reactants and product that has to represent a formulae. The amount of each element, number needs to be the same on either side of the equation. (E.g., HCl(aq)+NaHCO3(s) reacts to produce NaCl(aq)+H2O(I)+CO2(g)). This helps us view the study of the Law of Conservation of Mass, and how it works in this equation.
The concentration of the reactants solution 3. Temperature of experiment 4. Amount of time available for reaction 5. Amount of solid reactant 6. Amount of reactant solution Particle size
Stoichiometry is a chemical branch that studies amounts of substances that are involved in reactions. Stoichiometry will help you to find out how much of the mixture you will need, or how much you started with. The calculations of a stoichiometry problem depends on a balanced chemical equations. The factors of the balanced equations signifies the molar ratio (the number of moles of each reactant needed to form a certain numbers of moles of each product) of the reactants and products taking part in the reaction. From the atomic and molecular point of view the stoichiometry in a chemical reaction is very simple. For example, one mole of oxygen reacts with two moles of hydrogen,
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).
One vital process in the human body observed in chemistry is the idea of chemical kinetics. Chemical kinetics is the study of the rate of reactions, or how fast reactions occur.1 Three factors that affect chemical kinetics are concentration, temperature, and catalysis. As the concentration of a substance increases, the rate of the reaction also increases.1 This relationship is valid because when more of a substance is added in a reaction, it increases the likelihood that the
The rate of reaction is how quickly or slowly reactants in chemical reactants turn into products. A low reaction rate is when the reaction takes a long time to take place; hence, a reaction that occurs quickly has a high reaction rate. A rate refers to how slow or quick the product is produced. It is possible to control the rate of chemical reactions and speed up or slow down the rate of chemical reactions by altering three main factors which are temperature, concentration and the surface area. When the temperature of the reactants increases, the molecules vibrate at a more intense speed therefore colliding with each other more frequently and with increased energy resulting in a greater rate of reaction. Accordingly, as the temperature decreases the molecules will move slower, colliding less frequently and with decreased energy resulting in the rate of reaction decreasing. Concentration is how much solute is dissolved into a solution and is also a factor that affects the rate of reaction. When the concentration is greater this means there is an increased amount of reactant atoms and molecules resulting in a higher chance that collisions between molecules will occur. A higher collision rate means a higher reaction rate. Consequently at lower concentrations there are reduced chances of the molecules colliding resulting in a lower reaction rate. The measurement of how much an area of a solid is exposed is called the surface area. The quicker a reaction will occur the more finely divided the solid is. For example, a powdered solid will usually have a greater rate of reaction in comparison to a solid lump that contains the same mass for it has a lower surface area than the powdered solid.
t = time, a = volume of reactant, k is a constant of proportionality; x is the order of reaction. Because k is a constant of proportionality 1/t is directly proportional to the rate of reactant. Then to find out the order of reaction in a catalysed system the volume of ammonia molbydate is varied and the concentration of the other reactants kept the same. Thirdly to investigate the activation energies, the concentrations are kept the same and the temperature is varied.