junior chemistry-food chemistry-tea cake and baking soda.

Tea Cake and Chemistry
Not everyone is aware of the amazing chemistry that takes place in our very own kitchen in the process of making delicious cakes and meals. Here we will see the use of a chemical commonly known as baking soda in the making of a delicious tea cake.
Ingredients and utensils. Sieve 4 X eggs 300g Plain Flour 300g Apricot jam or any other jam of choice Teaspoon of Baking Soda 75mL of sunflower oil 1/4 cup of sultanas or any other dried fruit of choice. Oil spray to grease the baking tin with. Glass cup. Glass mixing bowl. 22cm round baking tin Whisk
Step 1 Place 300g of jam into a large glass bowl with one teaspoon of baking soda. Use a whisk to stir the mixture completely into a uniform consistency. Step 2 Once the baking soda and jam have been throughly mixed add four eggs and 75 mL of sunflower oil and again use a whisk to thoroughly mix the eggs and oil into the jam and baking soda mixture. Step 3 Use a sieve to slowly add 300g of plain flour to the mixture while stirring. Step 4 Now add 1/4 cup of dried fruit of your choice and once again stir the mixture well. Step 5 Prepare a baking tin by spraying lightly with oil and then using a tissue paper to spread the oil so that it covers the entire internal surface of the baking tin. Step 6 Place the glass cup upside down in the middle of the tin and pour the mixture in. Step 7 Bake for 25-30 minutes in a preheated oven at 180^oC .
Baking soda has the chemical name of sodium hydrogen carbonate with the formula NaHCO₃.
When NaHCO₃ is heated it decomposes into carbon dioxide gas, water and a harmless substance known as sodium carbonate Na₂CO₃.
Now, your tea cake will have some delicious flavours and an appetising smell. Flavours and smells are the products of many chemical reactions that take place when the dough mixture is heated. As for the fluffy, soft texture of the cake, well, that's due to a gas formed inside the dough mixture as it is heated in the oven. Not only does heat encourage the chemical reaction that forms this gas, but once formed, heat also causes the gas particles to form bubbles of gas in the dough mixture that expand to produce countless little air pockets that make the cake rise and increase in volume. Cakes are usually soft because of this reason.
The formation of carbon dioxide is an example of a chemical change. A chemical reaction often results in: a colour change the irreversible formation of a solid, liquid or gas. Bubbles in solution or an odor can indicate the presence of a gas.
Chemical reactions take place during cooking. A chemical reaction takes place when particles can mix together and collide with enough force to break apart and rejoin in different combinations to form new substances. The animation on the right shows how. 1. Use knowledge of particle theory to explain: - why is heating necessary in order to cook. - what happens to particles in the solid state when heated - what happens to particles in the liquid state when heated - what happens to particles in the gas state when heated.
2. Consider the particles shown on the right in the solid state. Suggest why they do not react, as depicted in the animation above, to form new substances.