Key Concepts

Substances react chemically in characteristic waysA set of reactions have the right to be provided to identify an unrecognized substance


Students will usage test liquids on various well-known powders and observe their reactions. Then students will certainly use these characteristic chemical transforms to assist them determine an unwell-known powder.


Students will be able to identify and control variables to develop a test to determine an unrecognized powder. Students will be able to explain that a substance reacts chemically in characteristic methods and also that these attributes deserve to be offered to determine an unwell-known substance.

You are watching: Baking soda and cream of tartar reaction


Downpack the student activity sheet, and also distribute one per student once specified in the task. The activity sheet will certainly serve as the “Evaluate” component of each 5-E leschild setup.


Be sure you and also the students wear correctly fitting goggles. When using tincture of iodine, follow all warnings on the label.

Materials for the Demonstrations

Baking sodaCornstarchCream of tartarTincture of iodineVinegarWater Universal indicatorGraduated cylinder or beaker2 droppers¼ teaspoon5 clear plastic cups3 Popsicle sticks

Materials for Each Group

Baking soda Baking powder Cream of tartar Cornstarch Water Vinegar Tincture of iodine Universal indicator 10 tiny plastic cups4 droppers8 Popsicle sticksTesting chart (laminated or spanned with wax paper)

Add iodine solution to baking soda and cornstarch to introduce the idea that different substances react chemically in characteristic methods.

Materials for the Demonstration

Tincture of iodineBaking sodaCornstarchWaterGraduated cylinder or beaker2 Popsicle sticksDropper¼ teaspoon3 clear plastic cups

Teacher Preparation

Make a dilute tincture of iodine solution by including around 10 drops of tincture of iodine to 100 mL of water. Pour 50 mL of this solution right into a clear plastic cup for this demonstration. Set the other 50 mL aside for the student activity. Instructions for preparing the remainder of the materials for the student activity are in the Explore area of this lesboy. Place ¼ teaspoon corn starch in a clear plastic cup and also ¼ teaspoon baking soda in one more cup. Do not tell students which powder is in each cup.


Tell students that you have actually a different powder in each cup. Both are white and look achoose, but they are chemically various. Explore

Introduce the activity and also ask students how they can test and also compare the 4 various powders through four various test remedies.

Tell students that in this activity they will test four various similar-looking powders via 4 different test solutions. The 4 powders are baking soda, baking powder, cream of tartar, and also cornstarch. The 4 test solutions are water, vinegar, iodine solution, and universal indicator. Exsimple that each powder will certainly react in a details way through each solution supplied to test it. Each powder and also solution pair is one collection of reactants. Let students recognize that in some cases, no chemical reactivity will occur.

Students will certainly have to observe and also record the reactions the liquids have actually via each powder.

Have students look at the testing chart. Point out that the names of the 4 test solutions are on the left and the names of the various powders are on the height.

Tright here is also one column for an unwell-known powder. Exsimple that after trial and error all four well-known powders and recording their monitorings, you will certainly offer students an unwell-known powder to determine.

Ask students concerns choose the complying with to aid them plan exactly how they will certainly organize and also conduct their tests:

Do we need more than one pile of each powder put on the chart? Yes. Each powder will certainly be tested with each of the 4 options so there needs to be four piles of each powder in the squares under its name.Should all the squares on the entire chart have actually samples of powder on them before you start testing?It is best if students place the four samples of one specific powder in its column on the trial and error sheet. Then students should test that powder through each of the 4 options. Students have to test a single powder with each of the test liquids before moving on to the following powder. Do the piles need to be around the exact same size?The size of the piles is not specifically crucial as lengthy as enough powder is provided to see a reaction, if tbelow is one. When trial and error the unwell-known, try to make the piles of unrecognized around the same size as the piles of the other powders.Should the variety of drops put on each pile be the same?The precise number of drops is not especially essential, although sufficient liquid have to be included to watch if tbelow is a reaction. When testing the unwell-known, be sure that the variety of drops provided on the unrecognized is the very same as the number offered on the various other powders.How will certainly you remember your monitorings for each reaction? Students must document their observations automatically after a single test solution is included to a powder. These will certainly be videotaped in a chart in the corresponding box on the task sheet.

As an instance, guide the class as they test baking soda through water, vinegar, iodine solution, and also global indicator.

Concern to Investigate

Can you use the characteristic means substances react to tell similar-looking substances apart?

Materials for Each Group

Baking soda in cupBaking powder in cupCream of tartar in cupCornstarch in cupWater in cupVinegar in cupTincture of iodine solution in cupUniversal indicator solution in cup4 Popsicle sticksTesting chart, either laminated or through a piece of wax paper over it4 droppers

Teacher Preparation

Each team will need 5 labeled cups each containing one of the powders and 4 labeled cups each containing among the 4 test solutions to finish all 3 of the tasks in this leskid.

Prepare the powdersLabel 5 little cups Baking Soda, Baking Powder, Cream of Tartar, Cornstarch and also Unrecognized.Place around ½ teaspoon of each powder into its labeled cup. These powders will certainly be tested in this activity.Place about ½ teaspoon of baking powder in the cup labeled unwell-known. Place the unwell-known cups aside. Students will test this unrecognized powder after they have actually tested each of the “known” powders and recorded their observations.Prepare the Test SolutionsLabel 4 cups Water, Vinegar, Iodine, and Indicator. Use the iodine solution left over from the demonstration or make a brand-new solution by adding 5 drops of tincture of iodine to 50 mL of water. Place about 5 mL iodine solution in a small labeled cup for each team.Make a global indicator solution by including 5 mL of global indicator to 100 mL of water. Place around 5 mL (or 1 teaspoon) indicator solution in a small labeled cup for each group. Some indicator solution will be left over for the demonstration at the end of the leschild.Place around 5 mL of water and also vinegar right into their small labeled cups.


Use the finish of a popsicle stick to place four equal piles of baking soda on the testing chart in the baking soda column. Let students know that they must not usage every one of the powder at this time. The continuing to be powder will be supplied in the Extfinish portion of this leschild.

Add 5 drops of water to the initially pile of baking soda. Record your observations in the chart on the activity sheet.

Continue experimentation each pile of baking soda through a different test solution and recording your observations.

Expected Results

There will be no change with water, bubbling with vinegar, and also little to no adjust via the iodine or indicator options.

Ask students:

What did you observe when each test solution was added to a sample of baking soda?Baking soda bubbles via vinegar. Tright here is no change with water or iodine solution. Students may watch a slight color readjust via the indicator solution. Exsimple to students that their outcomes display them the characteristic collection of reactions that baking soda has actually with these four test services. Would you intend each test solution to react via baking powder the same method as it did through baking soda? No. Each powder should have a different collection of reactions.

Have students conduct the tests on the staying powders and also document their monitorings.


Test each of the powders through the test solutions the way you tested baking soda and record your observations.

Expected Results

Table 1. Expected student results from combining test powders via test liquids.Test SolutionBaking SodaBaking PowderCream of TartarCornstarchWaterVinegarIodineIndicator
No changeBubblingNo changeNo change
Lots of bubbling that ends quicklyBubblingNo changeNo change
No changeBubbling, purpleOrangePurple
Greenish-blueBubbling, orange transforms to yellow with some greenDark oselection or pinkBrighter green, might have some orange

Give students the unrecognized powder and have them use their test options and monitoring chart to identify it.

Give each group the unknown powder. Exsimple to students that the unwell-known is one of the 4 powders they have actually tested and their project is to uncover out which one.

Ask students:

How might you test the unknown powder so that you could recognize it?Students need to realize that they will must test the unknown powder the same way they tested every one of the other well-known powders and also compare the results. If the unknown powder reacts via each test solution the very same means one of the well-known powders did, then these 2 powders need to be the same.

Concern to Investigate

Can you use the characteristic ways substances react to identify an unknown powder?

Materials for each group

Unwell-known in cup1 Popsicle stickTesting sheet4 test solutions4 droppers

Note: The unrecognized is baking powder.


Place 4 samples of your group’s unknown powder in the “Unknown” column on the trial and error chart.Test the unknown through each test solution in the very same method you tested each of the other powders.Compare the collection of reactions for the unrecognized with those of the various other powders.

Expected Results

The unrecognized will certainly react through each test solution the exact same way that baking powder does because the unwell-known is baking powder.


Have students report the identity of the unknown and also comment on what proof led them to their conclusion.

Tell students that they were able to usage their observations to recognize the unknown bereason each powder had actually its very own collection of characteristic chemical reactions via the test options.

Ask students:

What is the identification of the unknown?Baking powder is the unknown.Which monitorings led you to your conclusion? The unknown reacted through each test solution the very same means baking powder did.

Explain that each substance is consisted of of certain molecules which communicate via the molecules in each test liquid in a characteristic method. Several of these interactions result in a chemical reactivity and also others perform not. However, each monitoring students made is based on the way the molecules of each powder communicate through the molecules of each test solution.


Have students recognize the 2 substances in baking powder that make it bubble as soon as water is included.

Remind students that baking powder was the just substance that bubbled once water was added to it. Bubbling in a chemical reaction is a authorize that a gas is one of the products. Tell students that baking powder is a combination of various powders—baking soda, cream of tartar, and also cornstarch. Two of these 3 react with one another and develop a gas as soon as water is added. Students will should test every one of the feasible combinations of 2 powders through water. This means they deserve to figure out which two powders cause baking powder to bubble through water.

Question to Investigate

Which two substances in baking powder react through one an additional and produce a gas once water is added?

Materials for Each Group

Baking soda in a cupCornstarch in a cupCream of tartar in a cup3 Popsicle sticksToothpicksWax paperWaterDropper


Use separate popsicle sticks to area a tiny amount of two powders on a item of wax paper. Use a toothpick to mix the powders.

Use a dropper to add around 5 drops of water to the combined powders and record your monitorings.

Repeat measures 1 and also 2 till you have actually tested all 3 combinations.

Expected results

The 2 linked powders that bubble with water are baking soda and cream of tartar.

Demonstrate that vinegar and also cream of tartar are both acids.

Point out that the mixture of baking soda and also cream of tartar reacts through water to develop a gas. Baking soda and vinegar also react to develop a gas. Explain that carbon dioxide gas is developed in both reactions. Tell students that cream of tartar and vinegar have actually something else in prevalent that they will investigate in the next demonstration.

Concern to Investigate

Will vinegar turn global indicator solution pink the method that cream of tartar does?

Materials for the Demonstration

Universal indicatorCream of tartarVinegar2 clear plastic cupsPopsicle stickDropper

Teacher Preparation

Use the indicator left over from the lesson. Use vinegar and cream of tartar left over from among the student teams.


Pour about 25 mL of universal indicator solution in 2 separate clear plastic cups. Add 2 or 3 drops of vinegar to one cup.Scoop up a tiny amount of cream of tartar with the pointer of a popsicle stick and include it to the various other cup. Swirl both cups.

See more: Drag Each Image To Its Correct Step In The Process Of Translation.

Expected Results

The indicator in both cups will rotate pink.


Tell students that the shade transforms of indicator solution have the right to tell you whether a substance is an acid or not. Because global indicator turns pink once acids are added to it, we deserve to say that both vinegar and cream of tartar are acids. When an acid reacts via baking soda, carbon dioxide gas is developed.

Ask students

Why do you think the baking soda and cream of tartar reaction is equivalent to the baking soda and vinegar reaction?Cream of tartar and vinegar are both acids and also connect with sodium bicarbonate in a similar method to produce carbon dioxide gas.