How will altering the concentration of hydrochloric ( HCl ) acid affect the rate of H gas ( H2 ) production during the reaction with Mg ( Mg ) , utilizing the force per unit area buildup by H gas?IntroductionFactors that influence rates of reactions include alteration in concentration, temperature, surface country, or the add-on of a accelerator.

This experiment will specifically look into the consequence of concentration alteration of the reactants upon the rate of reaction, utilizing hydrochloric acid and Mg strip. The concentration of HCl acerb solution is controlled through consecutive dilution.2HCl ( aq ) + Mg ( s ) a†’ MgCl2 ( aq ) + H2 ( g )This experiment in peculiar will research how the force per unit area changes as the above reaction returns. Because the reaction produces H gas as a merchandise, constructing up more force per unit area within the confined infinite of a trial tubing, a force per unit area detector will mensurate the rate of reaction. After the reaction begins, about 20 seconds of informations will be collected with each test, in order to explicate a common tendency ( a graph of force per unit area over clip ) . With mean inclines of different sum of concentrations, a additive arrested development line will so be created to chalk out the tendency, sing the consequence of concentration upon pressure-the rate of reaction.


Harmonizing to Collision Theory, the reactant atoms must clash together, and therefore making a reaction. Because increasing the concentration of HCl acid solution besides means an addition in the figure of H and chloride ions, hit between the reactant atoms increases every bit good, ensuing in more products-hydrogen gas. With more production of H gas in the confined trial tubing, force per unit area will construct up.Therefore, if-at a given period of time-the concentration of HCl acerb solution additions, so the rate of reaction will increase consequently, because more hits will happen, bring forthing H gas at a higher rate.


Variable description

Method of mensurating variable

Dependent variable

Pressure buildup due to the reaction between hydrochloric acerb solution and MgDuring the reaction, H2gas is produced, therefore increasing the volume within the confined infinite of a trial tubing and increasing the force per unit area. This alteration will be recorded by a force per unit area detector. Collecting information for about 10 seconds before the injection of the Mg strip, the measuring of force per unit area will go on for approximately 20 seconds after the reaction begins.

Three tests are required for each concentration of HCl solution to minimise random mistake.Rate of reactionUsing the more accurate initial rate of the reaction, about 10 seconds of the graph after the reaction begins will be used to make a incline of alteration in force per unit area over clip.

Independent variable

Concentration of HCl solutionUsing consecutive dilution along with setup such as micropipette and flask, the 1M hydrochloric acerb solution will be diluted into 0.5M, 0.

25M, 0.125M, and 0.0625M.

Controlled variables

Mg strip ( length )Using a swayer and scissor, the Mg strip will be cut into 15 pieces, each being 1cm.Volume of hydrochloric acerb solutionFor each concentration, 3cm3of hydrochloric acerb solution is used, accurately measured by a pipette.Temperature of reactantsThe temperature remains changeless at room temperature ( approx. 25 grades Celsius ) throughout the full experiment.

Shaking of the trial tubingTo make the most accurate consequences possible, physical gesture when somewhat agitating the trial tubing must be insistent in the same manner for each test.Size of the trial tubingBecause different sizes of trial tubings would intend different volumes every bit good, changeless size ( volume ) is indispensable, sooner little so that the reaction will be more conspicuous. To make this, 15 indistinguishable trial tubings are used.Table 1: List of Variables

Apparatus and Materials

1M hydrochloric acid solutionDistilled H2OMagnesium stripFlask ( 50cm3 )Pressure detectorLogger ProMicropipette15 indistinguishable trial tubingsEmery paperScissor


Put 20cm3 of 1M HCL solution in the flask and thin it to 0.5M with 20cm3 of distilled H2O.Using the consecutive dilution as in measure 1, prepare 10cm3 solutions with concentrations of 1M, 0.5M, 0.25M, 0.

125M, and 0.0625M.Add 3 cm3 of each solution into labelled trial tubing utilizing the micropipette.Repeat measure 3 to fix three test tubings of each solution ( 15 in sum )Cut out the Mg strip into 15 pieces of 1cm and sand them with emery paper.Put the cut out Mg strip into the trial tubing with 1M HCl solution.Then rapidly cover the trial tubing with the force per unit area detector.Start roll uping informations while agitating the trial tubing in a consistent mode for about 25 seconds after the reaction begins.Repeat steps 6 to 8 for all other trial tubings.

Data Collection and Processing

Quantitative Data

Hydrochloric acid concentration / mol dm-3

Change in force per unit area over clip / a-?kPas-1

Trial 1

Trial 2

Trial 3




023930.12850.2759Table 2: Change in force per unit area over clip at different concentrations of HCl solutionQualitative DataAfter the injection of the Mg strip into the HCl solution, it effervesces and force per unit area inside the trial tubing begins to construct up.With trial tubings of higher concentration, the force per unit area seems to be higher within the clip bound and more bubbles signifier.At the terminal of the reaction, the solution ‘s colour changed to transparent yellow.The reacted solution ( merchandise ) gives off a foul odor.

Processed Datas

Concentration of HCl solution, mol dm-3


Average rate of reaction, a-?kPas-1

1= 1.44271.44270.5= 0.49240.49240.25= 0.18540.

18540.125= 0.23890.

23890.0625= 0.14280.

1428Table 3: Calculation of mean rate of reaction

Data Presentation

1 0.5 0.25 0.125 0.0625Figure 1: Graph of mean rate of reaction, kPa s-1 against concentration of HCl solution, mol dm-3


Standard DeviationStandard divergence was calculated and represented in the rate of reaction vs. concentration graph as mistake bars.

HCl concentration, mol dm-3

Change in force per unit area over clip,


Average rate of reaction,


Standard divergence

Trial 1

Trial 2

Trial 3








27590.14280.1266Table 4: Standard divergence for different concentration of HCl solutionStandard divergence was calculated by a graphing reckoner.Uncertainty due to the consecutive dilution of HCl solutionUncertainty due to 1cm3Uncertainty during dilution & A ; measuring force per unit area ( ? )


In Figure 1, the tendency of different concentrations of reactants act uponing the rate of reaction is illustrated. The additive arrested development line demonstrates the clear alteration in rate of reaction, harmonizing to the alteration in concentration-the lower the concentration, the slower the rate of reaction. Hence, the initial hypothesis, saying the direct relationship between concentration and rate of reaction, is justified and validated.


Shown by Table 4, in which the criterion divergences for each concentration of HCl solution are calculated, the consequences of this experiment are reasonably precise, but non to a great extent. Furthermore, uncertainnesss created during the readying of the experiment, as with the direction of setup and stuffs such as the gas force per unit area detector, flask, and micropipette decreases the truth.

Although Figure 1, the graph incorporating the general tendency of concentration ‘s consequence upon the rate of reaction seems to formalize the hypothesis, the rate of reaction of 0.25M HCl solution stands out of the tendency, diminishing the cogency of this experiment ‘s consequences.More factors that may hold hindered obtaining accurate consequences of this experiment include:




Using manus to agitate the trial tubing for faster reaction rateAny non-perceptible ( by worlds ) alterations influenced each reaction to continue otherwise, finally making different fortunes for each test. This alteration in fortunes is important since it greatly hinders accurate consequences.The usage of a quiver home base alternatively may cut down mistake as it is more consistent. Reproducible fortunes can be better achieved.


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