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Lab Exam Review

General Reminders

•NO PERSONAL PRONOUNS

•Materials should be organized (list or columns)

•Number the steps of the procedure

•Be specific in the procedure

General Reminders

• Procedure is written in present tense and starts

with a verb

• Record results and repeat steps (where needed)

• Data needs to be presented in an organized, neat

manner (use a table with a title)

General Reminders

In the conclusion:

• Restate the aim

• Restate the hypothesis

• Summarize test results and analysis

• 2 Sources of error and/or improvements (that are not

silly mistakes: mislabelling or miscalculating)

Testing for Identification

• Although non-characteristic properties can be shared by many

different substances, they can still be useful in helping to identify

an unknown

• Substances will have different combinations of non-

characteristic properties

• Some non-characteristic properties can be used to determine a

characteristic one (volume & mass are used to calculate density)

Testing for Identification

• You need to know how to conduct and analyze the results of the

following tests:

Electrical conductivity

Presence of water

Litmus paper

Presence of glucose

Presence of protein

Presence of fat

Colour

Electrical Conductivity

• How: Conductivity meter

• Possible outcomes:

• Light turns on = Substance conducts! Indicates

the presence of minerals/salts

• Light stays off – does not conduct

Presence of Water (H2O)

• How: Cobalt chloride paper

• Possible outcomes:

• Stays blue = No water present

• Turns light pink = There’s water present in the

solution!

Presence of Water (H2O)

Acid, Base or Neutral

• How: Red and blue litmus paper

• Possible outcomes:

• Red → Red, Blue → Blue = neutral

• Red → Blue, Blue → Blue = base

• Red → Red, Blue → Red = acid

Presence of Protein

• How: Biuret solution (protein test solution)

• Possible outcomes:

• Stays blue = No protein

• Turns purple = Protein is present in the solution

Protein or no protein?

Protein ProteinNo protein

Presence of Glucose

•How: Glucose test paper

•Possible outcomes:

• Stays yellow = No glucose

•Turns green = Glucose is present in the solution

Presence of Starch

•How: Lugol’s solution

•Possible outcomes:

• Stays yellow/orange= No starch

• Turns dark blue/black= Starch is present in the

solution

Presence of Fat

•How: Alcohol test

•Possible outcomes:

• Stays transparent = No fat

• Turns white and cloudy = Fat is present in the

solution

Review Question

Test/

Liquids

Acid Base Salt water Distilled

water

Alcohol

CCP √ √ √ √x

BLP √x x x x

RLP x √x x x

Conductivity √ √ √x x