Sherbet “Experiment”
Fill in the Blanks
Sherbert is an application of an Acid – Carbonate reaction. The general word equation for an
acid – carbonate reaction is
Acid
+
Carbonate
⇒
________
+
________
+
________
The acid used in the reaction is ___________ and the base used, is ____________. Icing
_________ and jelly crystals are added for flavouring. If we taste each ingredient separately,
we might find that the acid tastes ________ and the base tastes _________. We all love
sherbet because of the fizzing sensation it leaves in our mouth. This is due to the gas that is
made as a __________ of the acid __________ reaction
Sour
Carbon Dioxide
Bicarbonate
Bitter
Carbonate
Product
Salt
Citric Acid
Water
Sugar
Conducting your “Experiment”
Materials
-
Bicarbonate powder
Citric Acid powder
Icing Sugar
Jelly Crystals
Mixing bowl
Spoon
Feel free to try SMALL amounts of the
powdered materials before mixing them.
Reflect on how they taste before and after
being mixed together (i.e. taste the
reactants as well as the products) also
taste a bit of citric acid and bicarbonate
together in order to experience the taste
of the salt that’s produced.
Procedure
-
-
Add 1 teaspoon of citric acid, 2
tablespoons of icing sugar, 3
tablespoons of jelly crystals
and 1 teaspoon of baking soda
to your mixing bowl
Stir the ingredients together
well
Adjust ingredients according to
your taste
As a rough guide, take 1 teaspoon
to be = to ¼ of a table spoon
Analyse the Following Text and Answer the Questions
Citric Acid has a molecular formula of C₆H₈O₇ and bicarbonate/bicarb (or baking soda as
Americans might say) has a molecular formula of NaHCO3. Sodium Citrate (Na3C6H5O7) is a
salt that is produced when citric acid and bicarb react. It is described to have a distinct taste;
you often find this type of reaction in sherbet.
Label the overall charge on the following ions or leave them blank if they’re already
electrically neutral.
i)
C6H7O7
ii)
H
iii)
H2O
iv)
OH
v)
Na3C6H5O7
vi)
CO2
Check all the boxes that describe the chemical reaction that takes place in sherbet.
Is Exothermic (did your tongue feel
hotter)
Is a Neutralisation
Is Endothermic (did your tongue feel
colder)
Produces a gas
Is a Combustion
Raises pH
Which of the following equations is the correct, balanced formula for the reaction that takes
place in sherbet?
a)
b)
c)
d)
3C₆H₈O₇ + NaHCO3 ⇒ 2CO2 + H2O + 3Na3C6H5O7
C₆H₈O₇ + NaHCO3 ⇒ CO2 + H2O + Na2CO3
C₆H₈O₇ + 3NaHCO3 ⇒ 3CO2 + 3H2O + Na3C6H5O7
2C₆H₈O₇ + NaHCO3 ⇒ 2CO2 + H2O + Na2CO3
Exit Ticket
Write a journal entry in your books – roughly a paragraph – describing your experimental
procedure, your results, and your observations. Reflect on your observations and think
about how they relate to acids and bases. Give your opinion on what the best recipe for
sherbet might be.