EXPERIMENTAL PROBLEM n. 09 GROUP B

You have a given amount of sodium chloride (3,0 grams) in a small test tube. Your task is to put, in a second empty test tube, as many ions of potassium and chloride as they are in the 3,0 grams of NaCl, and then to compare the volumes of the two amounts of solids. You have also alcohol, cylinder and pipette.

1. Useful knowledge (reference data, concepts and principles)

first

second

third

fourth

2. Main idea

synthetic description of the whole strategy to accomplish the task

3. Planning

1. Detailed

2. sequence

3. of the manipulative steps only,

4. specifying which instruments to use

5. what should be measured

6. and observed in the laboratory

4.  Report

Description of the experiment,

raw data and measures (without calculations),

relevant detailed observations

pictures and descriptions of the most important stages of the experiment

drawbacks: solutions and planning changes

5. Elaborazione e Interpretazione

Data elaboration-calculation from raw data

deductions and interpretations from calculated data

conclusions: answering problem request. Other outcomes.

Questions & Answers

1. Question 1

Why is the amount of KCl more than three grams?

2. Question 2

What data you need to calculate volumes from masses, without measuring?

3. Question 3

Why are the volumes of the two salts so different?

4. Question 4

Why is a potassium ion bigger than a sodium ion?

Answer 4

5. Question 5

Which is the largest between:

a) a bromide ion and a chloride ion

b) a cesium ion and a cesium atom

c) a sodium ion and a magnesium ion

d) a iodine atom and a iodide ion

e) an oxygen atom and a sulphur atom