Name __________________________ lab partner(s) ___________________________ pd __
Kitchen Chemicals LAB
The chemical and physical properties of a substance make up a sort of fingerprint that
characterizes the substance. In this lab, you will test four unknown solids using three
different liquids. The unknowns are common materials that you’d probably find in your
kitchen. The results of your tests will give you the information you need to unravel the
compositions of mixtures of two and three solids.
Objectives:



Observe the chemical and physical reactions of four common kitchen solids with three test
reagents.
Compare and interpret the reactions of the test reagents with five different mixtures of the four
common kitchen solids (three mixtures will contain two different solids, two mixtures will
contain three different solids).
Infer the composition of each of the five unknown mixtures by comparing their reactions with
those of the known materials.
Materials:
Spot plate
White paper
Pen/pencil
solids “A, B, C, & D”
solid mixtures “#1, 2, 3, 4, & 5”
liquid reagents I, II, and III
Procedure:
1. Place the spotplate on a white piece of paper so that the shorter side is on the top and
bottom.
2. Label three long columns of wells I, II & III across the top. Label nine rows along the left
side A, B, C, D, 1, 2, 3, 4, & 5.
I II III
A
B
C
D
1
2
3
4
5
3. Add a SMALL amount of each solid to the row of three wells with the appropriate letter
or number.
4. Observe and record the color and texture of each of the nine solids in the data and
observations table.
5. Add 3 drops of liquid I to each of the nine solids in column I.
6. Observe any changes that take place (fizzing, color change to black, dissolving or no
reaction) and record them in the data table.
7. Repeat steps 5 & 6 using liquid II & III
Data and Observations
Solid
(pure)
A
(pure)
B
(pure)
C
(pure)
D
(2 solid mix)
1
(2 solid mix)
2
(2 solid mix)
3
(3 solid mix)
4
(3 solid mix)
5
Color
Texture
Reaction
with liquid I
Reaction
with liquid
II
Reaction
with liquid
III
Analyze and conclude
1. What properties and reactions characterize each of the four pure kitchen solids?
A - _____________________________________________________________________
B - _____________________________________________________________________
C - _____________________________________________________________________
D - _____________________________________________________________________
2. Can you positively identify the solids that are contained in any of the five mixtures? If
so, identify which pure solids (A, B, C, or D) are definitely in each mixture and explain
how you know.
Mixture
Contains
#
this/these solids:
(A, B, C &/or D)
1
(2 solid
mix)
2
(2 solid
mix)
3
(2 solid
mix)
4
(3 solid
mix)
5
(3 solid
mix)
Explanation of conclusion
3. If you are unable to conclusively identify the solids in any of the mixtures, what are
their LIKELY identities? Explain.
Mixture
#
PROBABLY
Contains
this/these solids:
(A, B, C &/or D)
Explanation of conclusion
1
(2 solid
mix)
2
(2 solid
mix)
3
(2 solid
mix)
4
(3 solid
mix)
5
(3 solid
mix)
4. Two of the four original solids, baking powder and baking soda, are often used in
making baked goods. What characteristic probably makes them useful in baking
(hint: it helps rise the dough)? Which two solids (A, B, C, or D) display this
characteristic?
5. Baking powder is a mixture of two or more compounds, and it reacts with water or
ANY other liquid that contains water. Baking soda is a single compound that reacts
with acidic solutions but NOT with water. Which of the solids (A, B, C, or D) do you
think is baking powder? EXPLAIN why.
6. One of the solids is starch, an organic compound. It produces a characteristic color
when combined with iodine. Which solid (A, B, C, or D) gave this reaction?