m20517 To determine what happens when an acid and an alkali are mixed 1.1 2009/03/17 03:23:12.504 GMT-5 2009/03/17 03:48:41.243 GMT-5 Helen Saayman Helen Saayman mark.horner@shuttleworthfoundation.org Helen Saayman Helen Saayman mark.horner@shuttleworthfoundation.org Helen Saayman Helen Saayman mark.horner@shuttleworthfoundation.org Science and Technology en

Step 1: It turned blue, because bicarbonate of soda is an alkali Step 2: No Step 3: It became lighter Step 4: It becomes much lighter and lime green OBSERVATION: Neutral

We have already discovered that a neutral solution is neither an acid nor a base. What can we expect to happen when and acid and a base are mixed together? Let's find out! Use a Bromothymol blue solution as indicator Other requirements: 100 ml white vinegar 150 ml bicarbonate of soda solution STEP 1: Add a few drops of the bicarbonate of soda solution to the

Bromothymol blue indicator. What do you observe? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ STEP 2: Add half of the vinegar to the bicarbonate of soda solution

Does this make the solution neutral? _____________________________________________________________________ _____________________________________________________________________ STEP 3: To determine this, you have to add drops of the mixture to the Bromothymol blue indicator.

What do you observe? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ STEP 4: If no change has occurred, add half of the remaining vinegar to the bicarbonate of soda solution and repeat step 3.

STEP 5: Test the solution again and repeat steps 3 and 4 until there is a change.

What do you observe? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ OBSERVATION: The vinegar and bicarbonate of soda formed a________________________ solution. It is neither an acid nor a base. The process by which acids are destroyed by bases, or bases by acids, is called NEUTRALISATION.

Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts. Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: organises and uses apparatus/equipment or sources to gain and record information; Assessment Standard 1.3: We know this when the learner evaluates data and communicates findings: generalises in terms of relevant aspects and describes how the data support the generalisation.