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Stoichiometry lab report, Lab Reports of Chemistry

this is a lab report on stochiometry

Typology: Lab Reports

2021/2022

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Dawson College
Department of Chemistry and Chemical Technology
Laboratory Report
Experiment # 02
Experiment Title: Solution Stoichiometry
Lab report done by: Aaida Hossain (2132500)
Partner: Rosalie Meunier
Presented to: Matthew Hachey
202-NYA-05, Section 03003
Date of the Experiment: 22-09-2021
Date of the Lab Report Submission: 06-10-2021
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Dawson College

Department of Chemistry and Chemical Technology

Laboratory Report

Experiment # 02

Experiment Title: Solution Stoichiometry

Lab report done by: Aaida Hossain (2132500)

Partner: Rosalie Meunier

Presented to: Matthew Hachey

202 - NYA-05, Section 03003

Date of the Experiment: 22- 09 - 2021

Date of the Lab Report Submission: 06- 10 - 2021

1.0 Introduction

Solution stoichiometry is the stoichiometry of chemical reaction carried out in solution. Classical

stoichiometric calculations involve the following steps:

  1. Starting with the mass of reactants, calculate the moles of the reactants.
  2. Write the balanced chemical equation for the reaction.
  3. Determine the limiting reactant
  4. Using the number of moles of the limiting reagent, calculate the number of moles of the

product that are expected, thence the expected mass of product (theoretical yield).

  1. Compare the expected mass of product with the mass that was actually obtained (actual

yield) by calculating the percent yield.

ร— 100 %

For solution stoichiometry, in the first step, the number of moles of reactants is calculated by

using the definition of the molar concentration:

Here, ๐‘› is the number of moles of reactant, ๐‘€ is the molarity of the solution and ๐‘‰ is the aliquot

of this solution being used.

In this experiment, aliquots of sodium carbonate, ๐‘๐‘Ž 2

3

, and calcium chloride solutions,

2

, are mixed and the reaction described by the following equation occurs:

2

3

2

3

The resulting precipitate is filtered, washed and dried and the mass of the precipitate obtained is

compared with the theoretical mass by calculating the %๐‘ฆ๐‘–๐‘’๐‘™๐‘‘. (1)

2.0 Objective

The objective of this laboratory is to study the reaction between calcium chlorite and sodium

carbonate. Hence, the aim is to experimentally determine the mass of calcium carbonate

produced and to compare it to our theoretical expected value by calculating its percent yield. (1)

3.0 Material:

  • Safety goggles
  • Lab coat
  • Lab manual
  • Filter paper
  • Weighing dish
  • Watch glass
  • 4 g of ๐ถ๐‘Ž๐ถ๐‘™

2

2

  • 100 mL volumetric flask
  • Distilled water

5.0 Results:

The table below shows the results of the experiment, and section 5.1 shows the sample

calculation used to find the values displayed in the table

Table 1: Lab results

Mass of the empty weighing dish. 2.7442 g

Mass of the weighing dish and the ๐ถ๐‘Ž๐ถ๐‘™

2

2

6.7480 g

Mass of the ๐ถ๐‘Ž๐ถ๐‘™

2

2

๐‘‚ 4.0 038 g

Moles of the ๐ถ๐‘Ž๐ถ๐‘™

2

2

๐‘‚ 0.02723 mol

[๐ถ๐‘Ž๐ถ๐‘™

2

], ๐‘š๐‘œ๐‘™ โˆ™ ๐ฟ 0.2723 M

[

2

3

]

0.3330 M

Volume of the ๐ถ๐‘Ž๐ถ๐‘™

2

solution used. 10.00 mL

Volume of the ๐‘๐‘Ž

2

3

solution used.

10.00 mL

Mass of the filter paper and the watch glass. 53.9009 g

Mass of the filter paper, the watch glass and

the dry final product.

54.1721g

Mass of the dry final product. 0.2712 g

Moles of ๐ถ๐‘Ž๐ถ๐‘™

2

used. 0.0027 mol

Moles of ๐‘๐‘Ž

2

3

used.

0.0033 mol

Limiting Reagent. ๐ถ๐‘Ž๐ถ๐‘™

2

Calculated mass of excess reagent

remaining in the mixture after the reaction.

0.06 g of ๐‘๐‘Ž

2

3

Theoretical yield 0.2700 g

Percent yield 99%

5.1 Sample Calculations

  1. Mass of product : final mass โ€“ initial mass

2

2

2

2

  1. Molar mass: addition of the molar mass of each element found in the reactant/product

according to the correct ratios.

2

2

๐‘‚ = ( 40. 08 + ( 35. 45 ร— 2 )) +

  1. Moles: ๐‘› =

๐‘š

๐‘€๐‘€

, where ๐‘› is the number of moles of the product, ๐‘š is the mass of the

product and ๐‘€๐‘€ is the molar mass of the product.

๐‘ก๐‘œ๐‘ก

2

  1. Molarity: ๐‘€ =

๐‘›

๐‘‰

, where ๐‘€ is the molarity, ๐‘› is the number of moles and ๐‘‰ is the total

volume of the solution.

2

  1. Moles: ๐‘› = ๐‘€๐‘‰, where ๐‘› is the number of moles, ๐‘€ is the molarity, and ๐‘‰ is the total

volume of the solution.

2

= 0. 27235 ๐‘€ ร— 0. 010 ๐ฟ = 0. 002723 ๐‘š๐‘œ๐‘™ ๐ถ๐‘Ž๐ถ๐‘™

2

  1. Limiting reactant: comparing the number of moles of the final product that a reactant will

create. The reactant that creates the least amount of moles of final product is the limiting

reactant.

2

3

2

3

By observing this balance equation, we find out the number of moles of each reactant is equal to

the number of moles of the final product.

3

2

3

3

2

3

3

The limiting reactant in this reaction is: ๐ถ๐‘Ž๐ถ๐‘™

2

  1. Mass of excess reagent : (total number of moles โ€“ number of moles used) ร— Molar mass

2

3

= ( 0. 00333 โˆ’ 0. 002723 ) ร— 105. 99 = 0. 06433593 ๐‘”

  1. Theoretical yield : number of moles calculated ร— Molar mass

3

= 0. 002723 ร— 100. 09 = 0. 2725 ๐‘”

  1. Percent yield

๐‘Ž๐‘๐‘ก๐‘ข๐‘Ž๐‘™๐‘ฆ๐‘–๐‘’๐‘™๐‘‘

๐‘กโ„Ž๐‘’๐‘œ๐‘Ÿ๐‘’๐‘ก๐‘–๐‘๐‘Ž๐‘™๐‘ฆ๐‘–๐‘’๐‘™๐‘‘

ร— 100 %

3

ร— 100 % = 99. 52 %

8.0 Appendix

8. 1 Procedure

8.3 Post-Lab Questions

  1. That would lower he final reported yield because it would reduce the concentration of the

solution, thus reducing the number of moles of the final product that can be possibly

formed.

  1. a) It is returned into the oven until it reaches it constant mass to make sure that all

moisture that was present in the final product has been evaporated

b) It would make the percent yield invalid because the mass of the final product weighed

would not only be bigger than the theoretical mass, but the final product would not be

pure as it contains other substances

  1. a)To get rig of any other substances stuck to the precipitate

b)The final dry product would not be pure as it would contain not only the precipitate but

any excess reactants/products

  1. a)Calcium carbonate is even les soluble in ethanol so washing the final product with this

substance would make the task of getting rid of any other substances easier.

b) The final dry product would not be pure as it would contain not only the precipitate but

any excess reactants/products

  1. a) 0. 00333 ร— 147. 012 = 0. 4885766 ๐‘” โˆˆ 10 ๐‘š๐‘™๐‘œ๐‘“๐‘กโ„Ž๐‘’๐‘ ๐‘œ๐‘™๐‘ข๐‘ก๐‘–๐‘œ๐‘› so, 4.8955 g in 100 ml of

solution.

b)Yes, the theoretical yield would change because in this case the theoretical mass is

0.4900 g.