Question

1. why do we need to know the chemical properties of substances in industries like medicine or construction? (2 points)

section b: application

1. a car is left outside during rainy weather and starts to form rust. a) what chemical property does this demonstrate? b) what evidence shows that a chemical change occurred? (3 points)
2. your friend says boiling water is a chemical change because bubbles are formed. do you agree or disagree? explain your reasoning. (3 points)
3. think about the last time you cooked food (boiling an egg, baking a cake, etc.). describe one chemical property involved in the process. (2 points)

section c: critical thinking

1. some metals like gold do not react with oxygen or water easily. why do you think gold is used in jewelry and electronics? (3 points)
2. imagine scientists discover a new metal that reacts violently with air. what precautions should they take when studying its properties? (3 points)

Explanation:

1. In medicine, knowing chemical properties helps in drug - design, interactions, and safety. In construction, it aids in material selection for durability and performance.
2. a) The car rusting demonstrates the chemical property of reactivity with oxygen (oxidation). b) Evidence of chemical change includes the formation of a new substance (rust, different from the original metal), color change, and loss of the metal's original properties.
3. Disagree. Boiling water is a physical change. The bubbles are water vapor, and no new substance is formed. Water in liquid and gaseous states is still H₂O.
4. When baking a cake, the chemical property of baking powder reacting with an acid (e.g., from buttermilk) to produce carbon dioxide gas is involved, causing the cake to rise.
5. Gold is used in jewelry due to its non - reactivity (it doesn't tarnish easily, maintaining its luster), and in electronics because of its excellent electrical conductivity and resistance to corrosion.
6. Scientists should work in a controlled, inert gas - filled environment (like argon), wear protective gear (gloves, goggles, lab coats), and handle it in small amounts to prevent violent reactions with air.

Answer:

1. In medicine, for drug - related aspects and safety; in construction, for material selection.
2. a) Reactivity with oxygen. b) Formation of new substance, color change, loss of original properties.
3. Disagree. No new substance formed; water vapor is just a state change of water.
4. Baking powder reacting to produce carbon dioxide in baking a cake.
5. In jewelry: non - reactivity for luster; in electronics: good conductivity and corrosion resistance.
6. Work in inert gas environment, wear protective gear, handle small amounts.