Investigation 2: Part 2-Citric Acid Saturation

Presentation Transcript

Citric acid is a weak organicacid found in citrus fruits. It is a natural preservative and is also used to add an acidic (sour) taste to foods and soft drinks.

If it does dissolve, how can you find out how much citric acid is needed to saturate 50 ml of wanter?

Work in pairs. Each group will get two bottles, but only one citric acid supply, syringe, and funnel.
Put 50 ml of water (one syringe) into each of the bottles. Then return the water and syringe to materials station.
Put a sticky note on the bottle, with the bottom of the note right at the water level. Use a bit of tape to secure the label.
Add citric acid one spoon at a time. Shake the bottle until the citric acid dissolves. Then add another spoon of citric acid.

Citric acid is more soluble than salt in water.
This means that more scoops of citric acid can fit into 50 ml of water, than salt.

How can we find out how many grams of citric acid it took to saturate 50 ml of water?

Place a labeled cup under the funnel.
Filter the solution using a wet filter paper. The saturated solution will pass through the filter; the undissolved salt won’t.
Place the saturated salt solution on one side of the balance and 50 ml of plain water on the other side.
Add gram weights to the plain water to achieve balance. The amount of mass added to the water is equal to the mass of salt dissolved in the saturated salt solution.
Record the number of grams of salt it takes to saturate 50 ml of water.