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The reactions of Zinc, Hydrochloric acid and Copper(II) Sulphate

HOW DOES IT WORK?

The experiments show the different ways that metal crystals and crystal lattices work. The one reaction shows where the bonds between the reactant molecules were broken to make a new reactant, and the second showed where no bonds were broken during the reaction.

Experiment 1:
To allow the formation of hydrogen gas in the reaction between zinc and hydrochloric acid.
Time Allocation: 45 Min

Zinc metal reacts with hydrochloric acid to form zinc(II)chloride and hydrogen gas. The gas is collected in a second test tube with downward displacement of air. To prove that the gas released is H2(g), a burning splint is brought to the mouth of the test tube. The gas explodes with a popping sound.

Experiment 2:
To allow the formation of water (H2O) by heating copper(II)sulphate pentahydrate.
Time Allocation: 45 Min

CuSO4∙5H2O(s) is known as hydrated copper(II)sulphate or copper(II)sulphate pentahydrate.

A small amount of blue CuSO4∙5H2O is heated in a test tube. Water droplets form in the cooler part of the test tube and the remaining CuSO4(s) changes into a grey-white colour. The process can be reversed by adding a few droplets of water to the anhydrous crystals.

 

EXPERIMENT 1: Reaction of Zinc and Hydrochloric Acid

AIM

To allow the formation of hydrogen gas in the reaction between zinc and hydrochloric acid

APPARATUS:

  • 100ml Beaker
  • Retort stand
  • Retort base
  • Retort Rod
  • Retort clamp
  • 2x test tubes
  • Rubber stopper
  • Spatula
  • Test tube rack
  • Test tube holder
  • 0,1 M Hydrochloric acid HCℓ(aq)
  • Zinc granules (Zn(s))
  • Spatula
  • copper(II)sulphate pentahydrate CuSO4∙5H2O(s)
  • Gas stove and Fuel cartridge
  • Wooden splinter
  • Electronic scale/compact balance
  • Matches or gas lighter
  • 10ml Water in dropper bottle

METHOD:

  1. Secure one of the test tubes in the rack and using a beaker, half fill the test tube with diluted Hydrochloric Acid HCℓ (aq).
  2. Using the spatula, measure 5g Zinc (Zn(s)) and add it to the hydrochloric acid.
  3. When bubbles become visible in the test tube, cover the mouth of the reacting test tube with the second test tube which you can secure upside down to the retort rod with the clamp
  4. Allow the reaction to take place until enough gas is collected in the test tube.
  5. Bring a flame of the lighter or burning splint to the mouth of the test tube and test the collected gas.
  6. Observe the ignition of the gas and any sounds and smells during the reaction.

EXPERIMENT 2: Product formation when heating Copper(II)Sulphate Crystals

AIM

To identify the substances that form when blue copper(II)sulphate crystals are heated.

APPARATUS:

  • Test tube
  • Spatula
  • Test tube holder
  • Water in dropper bottle
  • 15g copper(II)sulphate pentahydrate
  • Gas Stove and cartridge
  • Rubber stopper

METHOD:

  1. Use the spatula to transfer 2g copper(II)sulphate pentahydrate (CuSO4∙5H2O(s)) to test tube with a spatula.
  2. Place the rubber stopper on the test tube.
  3. Light the bunsen burner.
  4. Use the test tube holder to hold the test tube in the flame at a 45֯
  5. Note any observations.
  6. Allow the test tube to cool down and add a few droplests of water to the content, do not add water to the test tube while the contents are hot as this will cause the test tube to break!
  7. Note the observations.

PRECAUTIONS:

  • All chemicals and open flames must be considered as potentially dangerous.
  • Wear safety clothing when using the strong acid, HCℓ(aq) and handle with great care.
    • Emergency actions:Hydrochloric acid:
      • In the eye – flood the eye with gently-running tap water for at least 20 minutes. See a doctor.
      • Swallowed – Wash out the mouth with water. Do not induce vomiting.
      • Spilled on skin or clothing – Remove contaminated clothing. Drench skin with plenty of water. If blisters occur, see a doctor.
      • Spilled n floor, bench, etc. – cover with mineral absorbent (e.g. cat litter) and scoop into a bucket. Neutralize with sodium carbonate and rinse with water.