Science: Making Salt Crystals

 Hi there!

Today I will be talking about how I made salt crystals in my Acids & Bases unit in Science class.

Aim: 

To produce copper sulfate salt by reacting copper oxide with an acid.

Method: 

1. Add 20mL of sulfuric acid to a 100mL beaker. Heat the acid until it reaches 70°C. Turn off your Bunsen burner. 

2. Once heated, use a spatula to add pea-sized portions of copper oxide to the beaker. Stir the mixture for 30 seconds.

3. Repeat step 2 until no more will dissolve. Allow the beaker to cool. 

4. Fold the filter paper and place it in the funnel. Place funnel into the second beaker. 

5. Make sure the beaker is cool enough to hold at the top. The contents should still be hot. You may need your teacher to complete this step. 

6. Gently swirl the contents of the beaker to mix, and then pour into the filter paper in the funnel. Allow to filter through.

7. Rinse the beaker you used to heat the mixture previously, and place it back on top of your tripod filled with 50-60mL of water.

8. Place the evaporating basin on top of the beaker and carefully pour some of the solution from the beaker into the evaporating basin.

9. Gently heat the beaker until the solution in the evaporating basin has reduced by half. 

10. Leave the evaporating basin to cool. Once cool, move the evaporating basin to a warm place where it will not be disturbed (i.e. a window-sill) and observe over the next few days. Blue copper sulfate crystals should form. 

Results/Observations: 

When the powder was added and mixed in, it created a black solution. Once it was cool enough we filtered it and instead of being black, the water/liquid which drained out was a bright blue colour. When all of the black mixture had been drained and turned blue, we reheated the blue liquid until it reduced by half its previous size. This was done in the morning so, after approximately 24 hours this blue liquid had evaporated and disappeared, and in its place were bright blue salt crystals. 

Here is a photo of how the crystals turned out:

Discussion: 

Here is the experiments literal meaning/chemical equation of what we made:

A chemical equation is an equation which is used in science. Instead of using words such as 'reacts with' or 'and', you would use a '+' to signify this. To show what direction an equation is going to replace it instead of 'to form'  or an '=' symbol, an arrow is used to show this. 

However, when dealing with acids and bases (bases = alkalis) the chemical equation will be different. The acid and base will form a salt, not the type you sprinkle on food however. 

The name of a salt is made up of two parts: 

(The chemical equation for this is: 

(Magnesium hydroxide + Hydrochloric acid --> Magnesium chloride + water)) 

The acid and base will also create water. If there are equal parts of Hydrogen (acid) or H+ and Hydroxide (base/alkali) or OH−, you will get water, or H2O. It doesn't mean that this is drinkable water though!

There are 3 main types of acids we have learnt: nitric acid, sulfuric acid and hydrochloric acid. When these acids become a salt in an experiment, they become: nitrates, sulfates and chlorides. 

In the chemical equation we used, our metal (copper oxide (base/alkali)) started off as a powder. We added it until no more would dissolve to a 70°C beaker filled with the required amount of 20mL of sulfuric acid. We then filtered this solution which was pitch black through filter paper in a funnel into a beaker. Then, the most surprising thing happened, the filtered solution came out bright blue and in the form of water! Then to make the salt crystals, we poured our solution into an evaporating basin and placed it over a boiling beaker of water. Once our solution was reduced by half its size, we took it off the heat and let it evaporate all the water to leave us with blue salt crystals. 

 

Conclusion: 

This experiment worked. I was able to create copper sulfate salt with copper oxide and an acid. I would not do anything differently in this experiment. 

Thanks for reading!