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Law of Definite Proportions

Compounds contain the same elements in the same proportion by mass.

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Chocolate Cake and the Law of Definite Proportions

Chocolate Cake and the Law of Definite Proportions

In chemistry, the law of definite proportions dictates that any chemical compound always contains the same elements in the exact same proportions by mass. A good example is water, as it will always have the same composition regardless if it’s a drop of water or an ocean.

Credit: Deniss Mojado
Source: http://photography.mojado.com/archives/2004/04/27/chocolate_cake.php
License: CC BY-NC 3.0

I wonder if Grandma knew about the law of definite proportions. [Figure1]

 Let’s say you want to bake your grandmother’s famous chocolate cake using her recipe. It calls for proportions such as 1 cup of flour to 1/2 cup of water, or 3 cups of sugar to 2 cups chopped chocolate chips.

Creative Applications

1. How does this recipe demonstrate the law of definite proportions? How so?

2. If you wanted to make a bigger or smaller cake, how would you maintain the taste of the cake?

3. If you added only more flour or sugar, would you still have the same cake? Why or why not?

Image Attributions

  1. [1]^ Credit: Deniss Mojado; Source: http://photography.mojado.com/archives/2004/04/27/chocolate_cake.php; License: CC BY-NC 3.0

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