Reactions that release energy are called __________ reactions.

Indian tradition holds that storing water in brass pitchers prevents disease. Scientists have discovered that there is some truth in the tradition. The researchers collected river water samples and found fecal bacterial counts as high as 1 million bacteria per milliliter. However, they could detect no bacteria in the water after it had been stored for two days in traditional brass pitchers. Bacterial levels in plastic or earthenware containers remained high over the same period. How can brass, which is an alloy of copper mixed with zinc, make water safer to drink?

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Which of the following statements is true for all exergonic reactions?

a) The products have more total energy than the reactants.

b) The reaction proceeds with a net loss of free energy.

c) The reaction goes only in a forward direction:all reactants will be converted to products.

d) A net input of energy from the surroundings is required for the reactions to proceed.

Classify the following types of chemical reactions.

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DRAW IT The artificial sweetener aspartame, or NutraSweet®, is made by joining aspartic acid to methylated phenylalanine, as shown in the following.

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a. What types of molecules are aspartic acid and phenylalanine?

b. What direction is the hydrolysis reaction (left to right or right to left)?

c. What direction is the dehydration synthesis reaction?

d. Circle the atoms involved in the formation of water.

e. Identify the peptide bond.

All chemical reactions begin with reactants and result in new molecules called __________ .

Indian tradition holds that storing water in brass pitchers prevents disease. Scientists have discovered that there is some truth in the tradition. The researchers collected river water samples and found fecal bacterial counts as high as 1 million bacteria per milliliter. However, they could detect no bacteria in the water after it had been stored for two days in traditional brass pitchers. Bacterial levels in plastic or earthenware containers remained high over the same period. How can brass, which is an alloy of copper mixed with zinc, make water safer to drink?

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