• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Can one determine the coefficients of a balanced chemical equation by having the mass of a reagent, the mass of the dry product and by using stoichiometry?

Extracts from this document...


Purpose Can one determine the coefficients of a balanced chemical equation by having the mass of a reagent, the mass of the dry product and by using stoichiometry? Hypothesis If the mass of the aluminum and the mass of the dry product, copper, is known then the balanced chemical equation can be derived by converting the masses to moles by dividing by the empirical molar masses of the elements, and then one can do a mole to mole ratio between this product and the reactant to make a balanced chemical equation. In a balanced chemical equation the coefficients of the chemical equation are indicative of the ratio of moles of the reactants and the products in a reaction. Since molar mass is also the mass per mole of substance and one knows the mass, then if one divides the mass determined from the experiment by the molar masses of each element then logically one will get the number of moles of the substance. From there a mole to mole ratio can be done between the product and the reactant and since a chemical equation can not have a fraction as a coefficient, then the coefficients can be multiplied on both sides by a number that will get a whole number for both elements. Since the law of conservation of mass states that anything that any quantity of substance that is put into the equation must result in the same quantity coming out of it and vice versa. This means that the very same mole to mole ratio can be applied to copper(ii) chloride and aluminum chloride to get the coefficients on those compounds. Hence finding the balanced chemical equation of the reaction. Procedure 1. Before the experiment is performed, two data tables are constructed. This is crucial because the time in the lab must be used efficiently, and time cannot be wasted in creating data tables which must be used for recording qualitative and quantitative observations. ...read more.


In addition spray the copper with water so that any aluminum chloride clinging to the filter paper gets washed down to the bottom. This better isolates the copper, ensuring precision within the experiment. 17. Take note of the qualitative observations of the copper after filtering out the aluminum chloride and solution. This is to ensure that copper truly is the dry product of the reaction. Record all these properties in "Data Table 1 - Qualitative Data Table" and record it under "After Reaction". 18. Lay the filter paper out to evaporate out the water on the copper so that the precision of the experiment is being up-kept. Note that one should only lay it out for approximately twenty-four hours so that the copper does not oxidize. If the copper does oxidize, the mass of the perceived copper would increase and the precision of the experiment would be ruined. 19. After twenty-four hours repeat step 3 and come back and determine the mass of the copper with the filter paper on the OHAUS Precision Standard Weighing balance. This mass will help isolate the mass of the copper in later calculations. Record this mass in "Data Table 2 - Quantitative Data Table" under "Mass of Copper with Filter Paper(�0.01g)". Sample Data Table 1 - Qualitative Data Table Time Qualitative Observations Before Reaction During Reaction After Reaction Sample Data Table 2 - Quantitative Data Table Masses Values Mass of Aluminum(�0.01g) Mass of Copper with Filter Paper(�0.01g) Mass of Filter Paper(�0.01g) Data Collection and Processing Data Table 1 - Qualitative Data Table Time Qualitative Observations Before Reaction � Copper(ii) chloride solution has a teal colour. � It is also liquid and translucent. � Aluminum is a gray, ductile, shiny, solid metal. During Reaction � Solution immediately turns into a very dark green colour with quite a lot of bubbling. � Overtime the part of the aluminum in contact with the solution turns a brick red colour. ...read more.


chloride should be the same as the mass of the copper in the dry product. In addition the the mass of the chlorine in Aluminum chloride should be the same as the mass of the chlorine in the copper(ii) chloride. Finally to find the mass of the aluminum can be found by finding the total mass of aluminum chloride by multiplying the mass of the chlorine by the reciprocal of the percentage of chlorine in aluminum chloride. Then to find the mass of the aluminum one would have to take the percentage composition of aluminum in aluminum chloride and multiply it by this total mass. This then gets the mass of all the compounds you need. This method prevents any of the error that would result from the reaction since no copper is lost during this reaction and this also prevents the error from copper oxidizing or copper being dropped since the copper is never given the chance to react. In addition this process involves very little error since percentage composition is a known, definite, empirical amount with a negligible uncertainty and only the copper(ii) oxide actually has significant uncertainty. If one wants to resolve the issue of the vigorous reaction of copper(ii) chloride, one could simply turn down the heat so that the reaction is not as vigorous. In this case, heating a substance during a reaction will just lead to an increased rate of reaction. However, if the temperature is reduced, then the reaction will occur more slowly but the risk of losing the copper is reduced. If one wants to resolve the issue of the oxidization of the copper then one could simply watch over the copper or come at an earlier time(i.e: the morning) so that the amount of copper that has oxidized is minimized. The evaporation of the water on the copper would not take 24 hours, realistically it would probably only need 1 or 2 hours to occur. After these one or two hours one could come in to the lab and mass the copper. This ultimately minimizes the amount of oxidized copper. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Chemistry essays

  1. Investigate the rate of reaction of luminol in various factors. The objective was to ...

    This graph gives a curve, which means the reaction is second order with respect to H2O2. Moreover, if the graph of rate against (concentration)2 is plotted, and it gives a straight line, it also indicates the reaction is second order.

  2. The purpose of this lab was to observe chemical changes, to write balanced equations, ...

    Chloride solution and Sodium Hydroxide solution Cobalt (II) Chloride: -liquid (solution) -no odour -transparent -reddish in colour Sodium Hydroxide: -transparent -colourless -odourless -liquid (solution) -dark blue in colour -starts fogging becomes translucent, almost opaque at one point -solid precipitate formed which settled at the bottom of the test tube which starts off being blue then changes to a

  1. Investigating Stoichiometry - The table shows the mass of reactants potassium iodide and lead(II) ...

    The mixture stuck in the beaker and was not filtered would have decreased the percent yield. Finally, when the mixture was being filtered, some of the PbI2 precipitate passed through the filter paper and went into the filtrate. The filtrate was not filtered again, so some of the PbI2 was not calculated into the final mass of PbI2 produced.

  2. Determining the activation energy of a reaction, By using the experimental data and the ...

    Evaluation Although this experiment attempts to control the variables which may affect the results, the method leaves room for improvements. The clock was stopped when the observer could see a colour change in the mixture. However, this colour change was gradual, and this was especially true when the solutions were under lower temperatures such as 30?

  1. To determine the molecular mass of an unknown alkali metal carbonate, X2CO3.

    46.8 47.5 47.4 Table 1: Volume of HCl used to neutralize substance Z solutions in all trials. Qualitative Observations In each trial, it was observed that the solution?s color changed from yellow to orange. Bubbling could be seen while the reaction between substance Z and HCl was taking place.

  2. Percent Yield Lab. This experiment has proven that KI is the limiting reagent ...

    xPbI20.0120mol=1/2 X= 0.00602mol Theoretical Yield 0.00602*(461) = 2.78 g The limiting reagent should be KI. KI has the least amount of moles therefore you do not have enough to react with the excess Pb (NO3)2. Whereas PbI2has a higher amount of moles and will result to be the excess reagent.

  1. Electrolysis of copper sulphate

    The raw â mass results for each current setting are also shown on the graph for scatter reference. From the graph, it can already be seen that there is a gain in mass as the current increases. To some extent, the average mass deposited seems to show relationship of direct

  2. Research report on Stoichiometry

    Stoichiometry calculations can predict how elements and components diluted in a standard solution react in experimental conditions. Stoichiometry is founded on the law of conservation of mass: the mass of the reactants equals the mass of the products. In stoichiometry, you base everything off the ratios of a chemical formula.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work