Volume and Chemistry, Exercises of Chemistry

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Investigation

1B

Volume and

Chemistry

Investigation 1B: Volume and Chemistry

• How do we measure liquid quantities in

chemistry?

• How can we measure very small quantities?

Investigation 1B: Volume and Chemistry

Reading a graduated cylinder

A 100 mL cylinder – marked every milliliter (mL)

• This reads

77.0 mL

• Ignore the edges and

read the

meniscus

the flat part.

Investigation 1B: Volume and Chemistry

Part 1: Setting up

1. Measure out 100 mL of water into a graduated

cylinder.

2. Add 1 drop of food coloring to each of the 4

test tubes. Use a different color for each tube.

3. Add 20 mL of water

to each test tube.

Investigation 1B: Volume and Chemistry

Part 2: Calibrating a dropper

In the next part of the investigation youwill need to know the volume of one drop!How will you determine this small amountaccurately?1. Read and record the volume in

milliliters (mL) for 50, 100, and 150drops from a dropper bottle.Use colored water for readability(Do not use the colored water fromyour test tubes).

Investigation 1B: Volume and Chemistry

31

3.24.

2. Calculate the number of

drops per milliliter for eachof the 3 volumes.

3. Calculate the volume of

1 drop in milliliters.

drops

drops mL

mL mL

mL drop

drops

Part 2: Calibrating a dropper

Investigation 1B: Volume and Chemistry

Just because you can buy bleach in the grocery store does NOT meanit can’t be dangerous if misused. Bleach can irritate or permanentlydamage eyes, nose, and mouth. • Wear safety goggles.• Work slowly and deliberately.• Do not drip solutions on skin or clothing.• If bleach gets on your skin, rinse it off

immediately with cold water.

• If bleach gets in your eye(s), use the

eyewash and get immediate attention.

• Do not drink or inhale bleach!

Handling chemicals

Investigation 1B: Volume and Chemistry

1. Transfer 3 mL of one colored solution

into a smaller test tube.

2. Use the dropper to add drops of

bleach. Count the number of drops ittakes for the solution to be colorless.

3. Record the number of drops of bleach

for each colored solution in Table 2.

4. Empty the test tube, rinse it out, and

repeat the experiment with anothercolored solution. If you have time,do 2 trials for each color.

How manydrops of bleachto make thecolor vanish?

Part 3: A chemical reaction

How much bleach does it take to remove a stain?

Investigation 1B: Volume and Chemistry

Part 5: A chemical mystery

One of the colors is a mixture of two others. See if you candetermine which one is the mixture, and present experimentalevidence that supports your claim.

Investigation 1B: Volume and Chemistry

Part 6: Going further

a. Use the data from Table 1 and Table 2 to calculate how many

milliliters of bleach it took per milliliters of colored water. This tellsyou the percent volume of bleach you need to remove each color. b. Bleach is used in washing clothes because it chemically removes

stains. Suppose your washing machine holds 15 gallons of water.How much bleach would you add to remove a yellow food color stainwith the same concentration as your experiment? Use the followingequivalents:

gallon

mL

cup

mL

Chlorine bleachcauses a chemicalreaction Investigation 1B: Volume and Chemistry

What happened?