Predicting & Classifying Chemical Reactions
1.
Use a test tube rack to hold a clean test tube while you add solutions
2.
Use the designated pipet to fill a test tube about ¼ full with a 3 Molar solution of hydrochloric acid (HCl). (Keep this test tube in the rack – this reaction gets very hot!)
3.
Drop 3 or 4 small pieces of zinc into the test tube with the HCl.
4.
Capture the escaping gas by inverting a dry test tube over the mouth of the test tube containing the bubbling mixture.
5.
Let the reaction occur for a minute and use a match to light a wood splint.
6.
Hold the burning splint so that the flame is near the inverted test tube.
Quickly tip the upside down test tube so that it comes in contact with the flame. Do NOT put the burning splint down into the solution of the other test tube.
7.
If hydrogen gas is present, it will pop when ignited by the flame…a
“barking dog” noise will be heard.
8.
Record in your lab report: a.
observations b.
the type of reaction c.
the balanced equation
9.
Dispose of HCl & Zn waste by pouring it into the designated waste beaker.
10.
Rinse the test tube with water and turn it upside down in the test tube rack to drain. A paper towel should be placed under the test tube rack to absorb the residue draining from the inverted test tube.