SNC 2D
Name: ___________________
(develop a descriptive title for this experiment)
Introduction
Most water contains many other dissolved substances. When an ionic compound is added to water, it separates
into ions ex: sodium chloride (NaCl) will separate into Na+ and Cl- ions in water.
Well water from the ground contains dissolved ionic compounds. Cations like calcium (Ca2+), magnesium (Mg2+),
and iron (Fe3+), and anions such as chloride (Cl1), nitrate ((NO3)1-) and sulphate ((SO4)2-) are present.
Chemical tests are used to detect and identify ions. Tests involve mixing two solutions that produce a solid
(precipitate) and colour change, which indicates a positive test for ions.
In this investigation, you test for iron (Fe3+), chloride (Cl-), and sulphate (SO4)2-) ions dissolved in three different
water samples.
Purpose:____________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
Materials:
Procedure
Part 1
1. Complete the title, purpose, hypothesis (what ions do you expect in the water samples?), and materials
section on a separate piece of paper.
2. Examine the three sample solutions and the three testing solutions. Write down three physical
properties for each and fill in observation Table 1.
3. Add two drops of tester solutions to two drops of each of the sample solutions. Record your observations
particularly any changes in colour or formation of precipitate in Table 2.
4. Summarize your findings in Conclusion 1, by filling in the blanks with the appropriate ion.
Part 2
1. Place two drops of each water sample into three different spots on your tray. Observe the sample of water
and record observations in Table 3.
2. Add 1 drop of tester solution to each of the water samples. Record your observations Table 4.
3. Repeat for other two tester solutions in different water samples. Record your observations in Table 4.
Part 1 – Observation Table 1: Physical Properties of Solutions
Solutions
3 Physical Properties
Part 1 – Observation Table 2: Identifying Positive Tests for Ions
Silver (I) nitrate
Testers and formulas
Barium chloride
--->
Ions testing for:
Potassium
thiocyanate
RESULTS
Positive Samples
Potassium Chloride
Sodium sulphate
Iron (III) nitrate
Conclusion part 1:
1) Silver nitrate (Ag1+) tests for ________________________________ ions.
2) Barium chloride (Ba2+) test for _______________________________ ions.
3) Potassium thiocyanate (SCN1-) tests for ________________________ ions.
Part 2 – Observation Table 3: Physical Properties of Water Samples
Water Sample
3 Physical Properties
Part 2 – Observation Table 4: Testing for Ions in Water Samples
Testers
--->
Samples
Silver nitrate
Barium chloride
Potassium thiocyanate
Distilled Water
Well Water
Tap Water
Unknown
Analysis – complete the following questions on the computer.
1. What is meant by a “positive” test for an ion?
2. Write the chemical formulas for silver nitrate, sodium sulphate, barium chloride and iron nitrate.
3. How could you tell how much sulphate was present in two different solutions, by adding barium
chloride?
4. Describe problems you had when performing the lab. Suggest ways to improve the experiment.
5. Formally state which ions were found in each of the 3 water samples. What was your proof?
Where might the unknown sample come from (read introduction)?