Rate of Reaction Design Experiment 
Effect of concentration on the rate of reaction between a metal and an acid

Introduction

        In chemistry, chemical kinetics is the study of the factors affecting the rate of a chemical reaction. By definition, rate is the increase in the concentration of one of the products per unit time or decrease in the concentration of one of the reactants per unit time. Many factors trigger the rate of reaction, such as concentration, surface area and temperature. I will investigate the effect of concentration on the rate of reaction between a metal, zinc (Zn), and an acid, hydrochloric acid (HCl). According to the collision theory and based on my experimental results, I will prove my following hypothesis to either be correct or incorrect in theory.

Design (D)

Aim
        
To investigate the effect of concentration of HCl on the rate of reaction of zinc (Zn)) by measuring the volume of hydrogen produced.

Hypothesis
        As the concentration of the hydrochloric acid (HCl) is increased, the rate of reaction per unit time will increase up to a certain concentration too, until an increase in the concentration of the acid will no longer effect the reaction rate. According to the collision theory, the more concentrated the reactants the more collisions there will be per second per unit volume. As the reactants get used up, their concentration decreases. This explain why the rate get slower until stops to a constant value as the reaction proceeds.

Variables
        
Independent Variable: Concentration of hydrochloric acid (HCl)
        Dependent Variable: Volume of hydrogen (H
2) gas produced/collected
        Controlled Variable: Temperature, mass of zinc used, temperature of the hydrochloric acid, volume of the hydrochloric acid

Apparatus and Raw Materials

  • Stopwatch
  • Clamp stand
  • Delivery tube
  • 100ml Gas syringe
  • Magnetic stirrer
  • One-hole plastic stopper
  • One 250ml conical flask
  • Spatula
  • 100 ml measuring cylinder
  • Electronic balance
  • Zinc dust- 6 grams
  • Hydrochloric acid of varying concentrations (1M, 2M and 3M- 50ml of each)
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Diagram

Method

  1. Put a 250 ml conical flask on a magnetic stirrer.
  2. Insert the open end of a delivery tube into a one-hole plastic stopper and plug the mouth of the conical flask with the plastic stopper.
  3. Attach the other end of the delivery tube to a gas syringe and clamp it horizontally, making sure it doesn’t oppose gravity. (Set apparatus should look like the diagram above)
  4. Using an electronic balance, weigh out 0.2g of zinc dust in a piece of paper.
  5. Place the 0.2g of ...

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