Reaction Speed of Chemical Leavening Agents - KEY

Name Period _ Assign #

  1. What is a chemical leavening agent?

A chemical compound that gives off carbon dioxide.

  1. What is the common base used?

Baking soda.

  1. What is the difference between single-acting and double-acting baking powder?

Double-acting reacts twice, single-acting reacts once.

  1. What are four common acids used with baking soda to complete the second reaction necessary to avoid the formation of sodium carbonate?

Sour milk, lemon juice, vinegar, cream of tartar

  1. What is the advantage of double-acting baking powder over single-acting baking powder?

The majority of the reaction takes place in the oven.

  1. What gas is produced during chemical leavening reactions?

Carbon dioxide.

  1. Observe while the teacher makes each mixture. Record the observations on the chart below.

Observation Chart

Leavening Agent/Liquid Added

  1. 1 t. (5 ml) baking soda/1 T. (15 ml) cold water
  1. 1 t. (5 ml) baking soda/1 T. (15 ml) hot water
  1. 1 t. (5 ml) baking soda/1 T. (15 ml) cold water - Time - then heat it
  1. 1 t. (5 ml) baking soda/1 T. (15 ml) lemon juice
  1. 1/4 t. (1.5 ml) baking soda/1 T. (15 ml) cold water
  1. 1/4 t. (1.5 ml) baking soda/1 T. (15 ml) hot water
  1. 1 t. (5 ml) baking powder/1 T. (15 ml) cold water
  1. 1 t. (5 ml) baking powder/1 t. (15 ml) hot water
  1. 1 t. (5 ml) baking powder/1 T. (15 ml) cold water - Time - then heat it

Conclusions:

  1. Which mixture/s produced little or no reaction?

Numbers 1 and possibly 7.

  1. Why was there little or no reaction with those mixtures?

For number 1, there was no heat to react with the base; for number 7, the greatest part of the reaction of double-acting baking powder occurs when heat is applied.

  1. Which mixture produced the most immediate and powerful reaction?

Number 4.

  1. Which mixture/s were slow to react?

Number 7 was slow to start, and number 9 was slow until it was heated.

  1. Which reaction lasted the shortest time?

Number 4.

  1. Which reaction lasted the longest time?

Number 9.

  1. Did you see anything go off into the air during the reactions? What would explain this observation?

Yes , carbon dioxide is the gas produced, but water is a by-product of the reaction when soda is mixed with an acid and a liquid.

  1. When should you apply the information you learned during this experiment?

When making quick breads, using double-acting baking powder gives you more time to get the ingredients mixed and measured and the bread in the oven before the leavening reaction is over. When the majority of the leavening reaction occurs in the oven, the quick bread will raise better. Single-acting baking powder or soda and a base may react so quickly that the leavening reaction is over before the quick bread is mixed and ready to bake.