White Before Your Eyes

You have learned how to describe matter based on its physical and chemical properties. You have also learned some signs that can help determine whether a change in matter is a physical or chemical change. In this lab, you’ll use what you have learned to describe four substances based on their properties and the changes they undergo.

Objectives:

  1. Describe the physical properties of four substances.
  2. Identify physical and chemical changes.
  3. Classify four substances by their chemical properties.

Materials:

●baking powder
●baking soda
●corn starch
●iodine tagged eyedropper
●ice cube tray / ●iodine solution
●spoon
●sugar
●vinegar
●water
●graduated cylinder

Procedure

  1. Copy Table 1 and Table 2 shown below. Be sure to leave plenty of room in each box to write down your observations.
  2. Using a spoon, place a small amount of baking powder into three ice cube compartments. Use just enough baking powder to cover the bottom of the compartment. Record your observations about the baking powder’s appearance, such as color and texture, in the “Unmixed” column of Table 1.
  3. Use a graduated cylinder to add 3 mL of water to the baking powder in the first box. Stir with a spoon. Record your observations in Table 1 in the column labeled “Mixed with water”. Clean your spoon.
  4. Use a graduated cylinder to add 1 mL of vinegar to the second box of baking powder. Stir. Record your observations in Table 1 in the column labeled “Mixed with vinegar”. Clean your spoon, and rinse out your graduated cylinder.
  5. Use an Iodine tagged dropper to add five drops of iodine solution to the third dimple of baking powder. Stir. Record your observations in Table 1 in the column labeled “Mixed with iodine solution”. Clean your spoon. Caution: Be careful when using iodine. Iodine will stain your skin and clothes.
  6. Repeat steps 2-5 for each of the other substances (baking soda, cornstarch, and sugar). Use a clean spoon for each substance, and rinse out your graduated cylinder well between uses.

Name: ______Per. ___ Date: _____ Integrated Science 8 Honors

White Before Your Eyes: Physical and Chemical Changes Lab

Table 1: Observations

Substance / Unmixed / Mixed with Water / Mixed with Vinegar / Mixed with Iodine solution
Baking Powder
Baking Soda
Cornstarch
Sugar

Table 2: Changes and Properties

Mixed with Water / Mixed with Vinegar / Mixed with Iodine
Substance / Change / Property / Change / Property / Change / Property
Baking Powder
Baking Soda
Cornstarch
Sugar

Analyze the Results

  1. What physical properties do all four substances share?
  1. In Table 2, write the type of change - physical or chemical - that you observed in each substance. State the property that the change demonstrates.
  2. Classify the four substances by the chemical properties of reactivity with Water, Vinegar, and Iodine.

Table 1: Observations

Substance / Unmixed / Mixed with Water / Mixed with Vinegar / Mixed with Iodine solution
Baking Powder / white, solid, powder / bubbles, white liquid / bubbles, white liquid / black solid
Baking Soda / white, solid, powder / white liquid / bubbles, white liquid / light brown solid
Cornstarch / white, solid, powder / white liquid / white liquid / black solid
Sugar / white, clearish, solid, powder / clear liquid / clear liquid / light brown solid

Table 2: Changes and Properties

Mixed with Water / Mixed with Vinegar / Mixed with Iodine
Substance / Change / Property / Change / Property / Change / Property
Baking Powder / chemical / gas produced / chemical / gas produced / chemical / color change
Baking Soda / physical / mixture / chemical / gas produced / physical / mixture
Cornstarch / physical / mixture / physical / mixture / chemical / color change
Sugar / physical / mixture / physical / mixture / physical / mixture

Analyze the Results

  1. What physical properties do all four substances share?
  2. White, solids, powders
  3. In Table 2, write the type of change - physical or chemical - that you observed in each substance. State the property that the change demonstrates.
  4. Classify the four substances by the chemical properties of reactivity . For example, which substances are reactive with vinegar (acid)?
  5. Reacts with water - baking powder
  6. Reacts with vinegar - baking powder, baking soda
  7. Reacts with iodine - cornstarch, baking powder