Home Chemistry 3 – Molar Solutions
Last year, I had a go at preparing a known concentration 1M of Sodium Chloride (Salt). Using the instructions at Quora.
- How many grams of sodium chloride are required to prepare 250 mL of a solution of 1M sodium chloride?
In order to some chemicals for future use. I will use the same instructions to create a known concentration of Citric Acid, given I want to test the reactivity between this and various metals, in a similar way to my previous experiment in Home Chemistry 1
- Decide how much solution is needed – 250ml
- Determine Molar mass of Citric Acid
- According to PubChem this is 192.12g
- Work out how much solid powder is needed
- Given 1 Mol is the molecular weight in 1 litire of water
- We are producing 250ml – so need to weigh out ¼ of the molar mass
- 192.12 / 4 = 48.03g
- So based on the instructions I found for NaCl
- We need to dissolve 48.03g in 250ml of Water to produce 250ml 1 molar concentration of Citric Acid
- Refer to data sheet – We know that Citric Acid is a Irritant, therefore it would be prudent to stick the CORRECT label on the bottle storing the solution.
- Correctly label the bottle
- Wear goggles when preparing the solution
- Wear gloves and Lab Coat
- Clean Surfaces
- Wash hands when finished
- Scales or Balance
- Volumetric Flask *1
- Paper to write notes
- Paper to put on scales for powder
- Label saying 250ml 1 mol Citric Acid
- Label giving formula and Molar weight
- Irritant label
*1 As I don't have a volumetric Flask, I can use a 250 or 500ml Conical Flask
My weighing scales are only basic and do not measure to 2 decimal places, there for we can weigh out 48g. As this is for home chemistry, while accuracy is important, we can probably make minor compromises.
- Citric Acid Powder
Read fully first
- Prepare equipment
- Measure out 250ml Water
- Fold paper in ½
- Unfold paper
- Put paper on scales
- Ensure Scales are ZERO
- Weigh out required amount of Citric Acid Powder
- Pour powder in to flask and stir or move flask around in a circular motion*
- Pour solution in to suitable container
- Stick on labels
- Wash up and dry equipment
- Wipe down surfaces etc
- Wash hands
- Store solution safely
Note the fold in the paper,just makes this easier.
- You may need to pour small amounts in to the flash, and dissolve before adding more
Further reading and advice
There will be a related thread on Science Forums for this, as I want to double check everything is correct.
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