We will be looking at how you would test liquids. Although we are only going to look at six common liquids you might expect to find around the house, the methods for identifying the liquids are similar. The six liquids we will be learning to identify are water, vinegar, lemon juice, hydrogen peroxide, ammonia, and rubbing alcohol.
The first test we will do is a simple matter of observing the solutions. Some of the solutions will all look the same at first. But if you look close you will notice a difference. Shake all of the liquid vials and see what happens.
The second test we will do is wafting. This is an easy test and is one of the best at identifying the unknowns. But it is not as easy as it sounds. One thing a scientist does not want to do is put a chemical right under their nose and inhale. This is very dangerous. If the chemical is concentrated or a health hazard this can make you very sick or very dead. Therefore, what we do is hold the chemical container out in front of our faces by a few inches. Then we bring a hand toward our nose passing the hand over the top of the open container of the liquid. This will bring just enough of the vapors of the liquid to our noses to smell.
The third test we will do is to test the pH of the liquids. We do this by dipping the wood splint or pipette in the liquid and then touching it to a piece of pH paper. We then compare the color against the chart on the side of the vial the pH paper was in. If using a wood splint, break off the contaminated section of the wood splint when moving on to the next liquid for testing.
The last test will be test the reaction with active yeast. Add a very small pinch of dry active yeast to a drop of the liquids and record observations.
Alert: Goggles are to be warn for the duration of the lab. Wash your hands after the lab and if/when they come in direct contact with the substance. Always keep lids securely on all containers and the items in front of you away from the edge of the table. Be careful not to cross-contaiminate any substance.
Record observation in a data table, similar to the one below. pH 1-6 is an acid; pH 7 is neutral; pH 8-14 is a base
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