Lab Exam Review - mssulik.weebly.com
Transcript of Lab Exam Review - mssulik.weebly.com
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