Lab 5B: Types of Chemical Reactions

In class we completed Lab 5B dealing with chemical reactions.
I had completed the lab once before in Grade 10, but regardless, it's always good to do things a second time! You catch things you missed the first time.

The first thing you always need to do is wear your safety goggles. Mrs Chen caught me a few times without them and she is right, always safety first!

 During this lab, you get 7 test tubes and complete a reaction in each one. We later determined the chemical equations for the reactions.

Reaction 1: For reaction 1, you adjust a burner flame to high heat, and then using crucible tongs (safety first), you hold a 6 cm length of bare copper wire in the hottest part of the flame for a few minutes.

During this experiment, we were asked to take observations before, during, and after.

In Reaction 1, before attempting anything, we observed that the wire was stiff and copper coloured. During the experiment, part of the wire exposed to the bunsen burner began to glow, there was a slight kink, and it began to turn black. After the experiment, it was black.

We determined the chemical equation for this reaction was 2Cu + O2 --> 2CuO, and classified it as a synthesis reaction.

Reaction 2: In reaction 2, you clean an iron nail with a piece of steel wool so that the surface of the nail is shiny. The nail is then placed in a test tube and copper (II) sulfate is added so half of the nail is covered.
Before, we noticed that the iron nail was brown, and the solution was an intense blue. During, bubbles and a thick layer formed. After, a copper coloured outer coating grew, it was relatively thick and darker in colour.

We determined the chemical equation for this reaction was 1Fe + 1CuSO4 --> 1Cu + FeSO4 and classified it is a single replacement reaction.

Reaction 3: In reaction 3, solid copper (II) sulfate pentahydrate was put in a test tube so that it was 1/3 full. Then, using the test tube clamp, we held the test tube and its contests at an angle away, heated the test tube, and moved it back and forth over a burner flame. We continued heating until no change was observed. Before, the solution appeared to be powdery and sandlike. During, it turned white, steamed, and bubbled. After, it turned completely white on the outside, bubbled, with lots of steam and sizzling sounds.

We determined the chemical equation for this reaction was 1CuSO4 x 5H20 --> 1CuSO4 + 1H2O and classified it as a double replacement reaction.

Reaction 4: In reaction 4, we allowed the test tube and contests from Reaction 3 to cool. We then used a medicine dropper to add 2 or 3 drops of water to the test tube. Before, the appearance was dirty white with blue specks, and dry and hard. During, it became wet. After, the water was absorbing and the appearance was a light colour.

We determined the chemical equation for this reaction was 1CuSO4 + 5H2O --> 1CuSO4 x 5H20 and classified it as a double replacement reaction.

Reaction 5: For this reaction, we filled a test tube 1/4 full with calcium chloride solution. Then we filled a second test tube full with sodium carbonate solution. We then poured the calcium chloride solution into the test tube containing sodium carbonate solution. Before, the solution appeared to be clear. During the reaction it foamed, became a cloudy white, and after it was thicker, gooey and a dirty white colour.

We determined the chemical equation for this reaction was 1CaCl2 + 1Na2CO3 --> 2NaCl  + 1CaCO3 and classified it as a double replacement reaction.

Reaction 6: With this reaction, we placed a piece of mossy zinc in a test tube. Then added hydrochloric acid solution to the test tube until the mossy zinc was completely covered. Before, it appeared to be exactly what it was called - mossy zinc. During, it expanded, bubbled, and turned a grey sandy colour. After, it slightly hardened and condensed, and became a solid.

We determined the chemical equation for this reaction was 1Zn + 2HCl --> 1H2 + 1ZnCl2 and classified it as single replacement.

Reaction 7: For this reaction, a test tube was half filled with hydrogen peroxide solution. Then, a small amount of manganese (IV) oxide was added. We tested the gas by placing a glowing splint into the mouth of the test tube. Before, we observed that the liquid was clear. During the experiment, it foamed up and seperated. After, it bubbled from the middle, steamed with the glowing splint, turned grey at the top (light) and the top resembled a candle wick.

All in all, it was a pretty cool lab! Here are some videos, some that were shown to us by Ms Mak last year, and some I personally recommend!

This is my favourite!
Several reactions, including single and double replacement!
Animations on reactions!
Who doesn't love a little Bill Nye?

Thats it for now! Have a great long weekend!

Ilanna