✅ 1. Required Practical: Making A Soluble Salt Flashcards
What is Hydrated Copper (II) Sulphate and the Aim of this Practical
Hydrated Copper (II) Sulphate is a soluble salt. It has several uses, including to in Bordeux mixture to control the growth of fungus on grapes, melons, and berries.
In the practical, you are going to make a pure sample of the soluble salt hydrated copper (II) sulphate, CuSO4.5H2O
Health and Safety for Making A Soluble Salt
- The Acid is an irritant
- Copper compounds are harmful
- Do not allow the acid to boil
- Be careful of hot apparatus
- Wear safety goggles
Equipemnt List for Making a Soluble Salt
- Stiring Rod
- 100cm^3 Beaker
- Sulphuric Acid
- Copper Oxide
- Tripod
- Heatproof Mat
- Gauze
- Bunsen Burner
- Filter Funnel
- Filter Paper
- Conical Flask
- Evaporating Basin
- 250cm^3 beaker
Method for Making a Soluble Salt
- Measure out around 25cm^3 / 30cm^3 of sulphuric acid using a measuring cylinder, and place it in a 100cm^3 beaker.
- Gently warm the mixture using a Bunsen burner. Do not boil the acid.
- Add a spatula load of copper oxide and stir. After a short time, the black copper oxide will all react producing a blue solution.
- Keep adding copper oxide one spatula at a time until it no longer reacts. You will be able to tell because there will be unreacted blck solid in the mixture.
- Filter and wash the mixure into a conical flask.
- While the mixture is filtering, set up a water bath using a half full 250cm^3 beaker of water on a gauze above a Bunsen. Start heating the water.
- Write your name on the evaporating basin using a marker pen.
- Once the filtration is complete, transfer some of the filtrate to an evaporating basin (do not more than half fill the basin).
- Carefully place the basin on the water bath and heat to allow some of the water the evaporate from the copper sulphate solution. If time allows, keep heating until crystals start to appear and then stop heating.
- Once the basin is cool enough to move, go and put it in a safe place to cool until the next lesson.
- In the following lesson, filter, wash, and dry your crystals of copper sulphate (you can dry then using filter paper.
What is the Word Equation for this Practical
Copper Oxide + Sulphuric Acid –> Copper (II) Sulphate + Water
Why was more Copper Oxide than the Sulphuric Acid amount needed used to make the Copper Sulphate
More copper oxide was need to make the Copper Sulphate because the Sulphuric Acid was the limiting reactant, so this way you could make sure that all the reagents are used up, with the Copper Oxide being in excess.
Why was the water not all boiled off from the copper sulphate solution
Not all of the water was boiled off the copper sulphate solution because it would’ve made anhydrous copper sulphate, which won’t give as frequent and large crystals as hydrous copper sulphate would. (Because boiling all the water takes the hydrogen away).
Why was a measuring cylinder used rather than a burette or pipette to measure out the acid?
A measuring cylinder was used, rather than a pipette, because you don’t need it to the same degree of accuracy as you would’ve needed in a titration, for example.
Independant Variable Definition
An Independant Variable is the variable that is altered during a scientific experiment.
Dependant Variable Definition
A dependant Variable is the variable being tested or measured during a scientific experiment.
Control Variable Definition
A Control Variable is the variable that is kept the same during a scientific experiement.
How is the excess Copper Oxide removed?
The excess copper oxide was removed by using the filtration technique, so the liquid is separated from the excess.
Why will more of the Metal Oxide be needed when making a Soluble Salt (+ how do you make sure that there is no left over acid or metal oxide)
More Metal Oxide is added because it is the substance in excess, and having more of this ensures that the acid (the limiting reactant) is fully used up (so the acid can’t contaminate the crystals at the end). After this, the excess Metal oxide can be filtered out of the solution.
