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Identifying Substances Lab Report

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Identifying Substances Using Properties Purpose: To identify unknown substances by observing their physical and chemical properties (e.g. colour, state, clarity, crystal shape, behaviour in water, behaviour in acid), and comparing them to the physical and chemical properties of known substances. Hypothesis: I predict that by observing and testing the properties, as well as comparing them to those of known substances, we can identify all 5 of the unknown substances. I think this will happen because every substance has a physical and/or chemical property or properties that differentiates it from other substances, no matter how similar. For example, baking powder and baking soda. These two substances are similar physically – white, powdery, …show more content…

I hypothesized that by observing the chemical and physical properties of an unknown substance whilst comparing them to data of known substances, we can identify the unknown substance. We were able to find the identity of all of the solids by comparing the results to the ‘Data About Solids’ chart. 10 b) I decided on the identity of the five solids by observing their physical and chemical properties, and comparing it to the data about the solids. I decided that sample A was baking soda, because of its reaction with acid. When the two drops of hydrochloric acid was added, the baking soda fizzed before dissolving quickly. However, I almost mistook the baking soda for chalk because they are both similar physically - white, opaque, powdery - but sample A's reaction with acid confirmed it was baking soda. I identified sample B as salt, because of its crystal form. I nearly mistook salt for sodium nitrate because they are both solid, white, clear, soluble in water and dissolves in hydrochloric acid. However, salt is the only solid where its crystal form is small cubes, so that is how I confirmed that sample B was …show more content…

I almost mistook the sodium nitrate for salt because they also have similar chemical and physical traits - they are both solid, white, clear, soluble in water, and dissolves in acid. However the sodium nitrate has crystal shape which is granular, and that is different from salt's crystal form, which is cubic. That is how I confirmed that sample C was sodium nitrate. Sample D was identified as sodium thiosulphate because of a chemical property – its reaction to acid. When the two drops of hydrochloric acid was added, the sodium nitrate turned cloudy and yellow, which is a distinct trait of sodium thiosulphate. I did not mistake this substance for any other substance because its reaction with acid is what confirmed that it was sodium thiosulphate. Sample E was identified as chalk because of its behaviour in water, also known as its solubility. After the two drops of water were added to the chalk, and it was mixed, with a clean toothpick we saw that sample E did not mix with the water. Chalk is the only solid, out of the five, that is insoluble. I almost mistook sample E for baking soda because the two substances have very similar physical traits. Both substances are white, solid, opaque and a powder. However, chalk's reaction to water and acid is different from baking soda. The chalk is insoluble with water, and its reaction with acid is that it fizzes and some dissolves. Meanwhile, baking soda is soluble with water, and

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