Fe³⁺(aq) + SCN^- (aq) <==> Fe(SCN)²⁺(aq); exothermic

1) Half-fill two semi-micro test tubes with Fe(SCN)²⁺ solution.

2) Place one test-tube in ice-water. Carefully heat the other test tube until the solution almost boils.

3) Compare the colour of the mixtures in the two test-tubes. Recrod your observations.

 

H₃PO₄(aq) <==> H₂PO₄^- (aq) + H⁺(aq); exothermic

1) Pour 1 M phophoric acid into each of two semi-micro test-tubes, to a depth of about 3 cm. Add two drops of methyl violet indicator to each test-tube.

2) Place one test-tube in ice-water. Carefully heat the other test-tube until the solution almost boils. Record the colour of the indicator in the heated and cooled test tubes.

3) Note the acidity of each solution. Methyl biolet indicator is yellow in solutions with a high concentration of H⁺(aq). Its colour changes through green, blue violet as H⁺(aq) concentration reduces.

 

N₂O₄(g) <==> 2NO₂(g); exothermic

1) Carefully place one of the stoppered test-tubes containing an N₂O₄/NO₂ gas mixture in a beaker of hot water for about one minute, holding the stopper firmly in place. Place the other tube in a beaker of ice-water.

2) Remove the test tubes from the hot water and ice-water and immediately compare the intesities of the brown colour in the tubes. Record your observations.

 

My question is: Does anybody know what these observations are (the colour changes of solutions in each semi-micro test-tubes)? This practical activity was done whilst I was away from class and I must do a practical report on it. None of my classmates recorded the results (or remembered them) and my teacher does not have the results. I'm guessing at least some people would have done this experiment here. If anyone could help out it would be appreciated!

These are very common demonstrations. Just to see, using Google, I was able to find enough information for each of these three observations. Give it a try and let's see what you come up with.

If your teacher doesn't have the results then how can they mark your work?

These are very common demonstrations. Just to see, using Google, I was able to find enough information for each of these three observations. Give it a try and let's see what you come up with.

 

Stop speaking in riddles and help me. If you know what these observations were then I didn't really need to research, did I?

 

I'm not lazy, I tried for 20 minutes and my internet is slow.