date of experiment: 15/1/2013
Experiment n1, n2: ELEMENTS AND COMPOUNDS
Background info:
We could learn many important
things about elements: their chemical representation, their colour, their melting
and boiling point, if they react with acid or not etc.
Aim:
In this experiment we are going to investigate nitric acid, potassium iodide hexane and Zinc in seventeen different points and represent all of them in a table. We will represent in a table all these kind of
compounds and elements in the following various different aspects:
Element/compound, chemical
representation, smell (y/n - strong/light), color, shine, aggregation state,
melting point, boiling point, magnetism, combustibility, conductivity, solubility in water, solubility in organic
solvents, r. vs. water, r. vs. OH-, r. vs. H+ and pH acq. sol.
Materials:
- Nitric acid (60%)
- Hexane
- Zinc
- Potassium Iodide
- Potassium Iodide
- Hydrochloric acid (60%)
- Bunsen burner
- Test tubes (x4)
- Test tube holder
- Goggles
- Lab coat
- Thermometer
- Magnet
- Water
- Organic solvent
- pH indicator paper
- Porcelain tray to test test the combustibility
- An open circuit to test if they conduct electricity
- Lighter
Procedure:
1. Observing whether it is an element or compound is easy. Starting with nitric acid we know that is a compound containing hydrogen, oxygen and nitrogen atoms, so it is denominated a compound.
2. We can see the chemical abbreviation in the bottle or we could formulate it. Is HNO3.
3. The next step is to test if it smells or not and if its a strong or light smell. In the case of an acid like nitric acid we need to open the bottle and with the hands move air towards our nose, this way we don´t damage senses. Yes, nitric acid smells lightly.
4. Colour, this is easy, just drop some nitric acid in a test tube and analyze it. Nitric acid is colorless (Do not through away the content of the test tube, keep it in the test tube holder).
5. Look at the test tube and see if it is shiny. Nitric acid does not shine.
6. Look at the substance and see what its aggregation state is. Nitric acid aggregation state is liquid.
7. To analyse the melting and boiling points, we need to research it on the internet fist to know if is possible to prove it. Nitric acid melting point is at -42ºC yet its boiling point is 83ºC so it is possible to determine it.
Set fire in the bunsen burner and introduce the thermometer in the test tube with nitric acid that we keep and determine the temperature in which starts to boil.
8. To determine if its magnetic, pass the magnet near it and if the liquid is magnetic will follow the magnet. Nitric acid is not magnetic.
9. Now we are determining if it is combustible adding some drops on the porcelain tray and carefully setting it alight. Nitric acid is combustible.
10. Is it a conductor? We are introducing an open circuit to determine it, we introduce the two extremes (negative and positive) without touching each other. Nitric acid is not a conductor.
11. To determine its solubility in water we introduce something more than a few drops of nitric acid and the same amount of water in a test tube. Yes, nitric acid is soluble in water.
12. Repeat the process from step 11 but with an organic solvent (hexane). Yes it dissolves too without reacting.
13. Repeat the process from steps 11 and 12 and see if it reacts. Yes it does.
14. Now we are adding few drops of nitric acid in the porcelain tray and cutting a very small piece of litmus paper, we introduce it carefully in it and depending in the color that it turns we could see if is acidic (red), neutral or alkaline (blue). The paper with nitric acid turns pink, meaning that is acidic.
15. Repeat the process with the others substances and make a table including all the results.
Video showing the combustibility of hexane:
Results:
Below, we can see the results obtained for each of the elements mentioned above organised in a table.
+6.35.41+PM.png)
Now, we can see the results of our classmates, the elements that the students from our class used to perform the experiment.
- Lighter
Procedure:
1. Observing whether it is an element or compound is easy. Starting with nitric acid we know that is a compound containing hydrogen, oxygen and nitrogen atoms, so it is denominated a compound.
2. We can see the chemical abbreviation in the bottle or we could formulate it. Is HNO3.
3. The next step is to test if it smells or not and if its a strong or light smell. In the case of an acid like nitric acid we need to open the bottle and with the hands move air towards our nose, this way we don´t damage senses. Yes, nitric acid smells lightly.
4. Colour, this is easy, just drop some nitric acid in a test tube and analyze it. Nitric acid is colorless (Do not through away the content of the test tube, keep it in the test tube holder).
5. Look at the test tube and see if it is shiny. Nitric acid does not shine.
6. Look at the substance and see what its aggregation state is. Nitric acid aggregation state is liquid.
7. To analyse the melting and boiling points, we need to research it on the internet fist to know if is possible to prove it. Nitric acid melting point is at -42ºC yet its boiling point is 83ºC so it is possible to determine it.
Set fire in the bunsen burner and introduce the thermometer in the test tube with nitric acid that we keep and determine the temperature in which starts to boil.
8. To determine if its magnetic, pass the magnet near it and if the liquid is magnetic will follow the magnet. Nitric acid is not magnetic.9. Now we are determining if it is combustible adding some drops on the porcelain tray and carefully setting it alight. Nitric acid is combustible.
10. Is it a conductor? We are introducing an open circuit to determine it, we introduce the two extremes (negative and positive) without touching each other. Nitric acid is not a conductor.
11. To determine its solubility in water we introduce something more than a few drops of nitric acid and the same amount of water in a test tube. Yes, nitric acid is soluble in water.12. Repeat the process from step 11 but with an organic solvent (hexane). Yes it dissolves too without reacting.
13. Repeat the process from steps 11 and 12 and see if it reacts. Yes it does.
14. Now we are adding few drops of nitric acid in the porcelain tray and cutting a very small piece of litmus paper, we introduce it carefully in it and depending in the color that it turns we could see if is acidic (red), neutral or alkaline (blue). The paper with nitric acid turns pink, meaning that is acidic.
15. Repeat the process with the others substances and make a table including all the results.
Video showing the combustibility of hexane:
Results:
Below, we can see the results obtained for each of the elements mentioned above organised in a table.
+6.35.41+PM.png)
Now, we can see the results of our classmates, the elements that the students from our class used to perform the experiment.
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