Question

20 match the following attributes with the correct answer. choices may be used more than once. _ created through a reaction that changes the properties of the elements a. pure substances _ examples: oxygen, aluminum, gold b. physical mixtures _ mixed in any proportion c. chemical compounds _ examples: salt water, pure air, concrete, powders _ examples: water (h₂o), salt (nacl), ammonia _ composition does not vary

Explanation:

To solve this matching problem, we analyze each attribute based on the definitions of pure substances, physical mixtures, and chemical compounds:

1. "created through a reaction that changes the properties of the elements"

Chemical compounds are formed when elements chemically react, and their properties differ from the elements. So this matches c. chemical compounds.

2. "examples: oxygen, aluminum, gold"

Oxygen (element), aluminum (element), and gold (element) are pure substances (elements are a type of pure substance). So this matches a. pure substances.

3. "mixed in any proportion"

Physical mixtures (like solutions, suspensions) can have components mixed in any ratio (e.g., different amounts of salt in water). So this matches b. physical mixtures.

4. "examples: salt water, pure air, concrete, powders"

These are mixtures (salt water is a solution, air is a gas mixture, concrete/powders are heterogeneous mixtures). So this matches b. physical mixtures.

5. "examples: water (H₂O), salt (NaCl), ammonia"

These are compounds (formed by chemical bonding of elements, with fixed composition). So this matches c. chemical compounds.

6. "composition does not vary"

Pure substances (elements or compounds) have a fixed, unchanging composition. So this matches a. pure substances.

Final Matches:

1. c. chemical compounds
2. a. pure substances
3. b. physical mixtures
4. b. physical mixtures
5. c. chemical compounds
6. a. pure substances

(Note: If the question expects one answer per blank, list them in order as: c, a, b, b, c, a)

Answer:

To solve this matching problem, we analyze each attribute based on the definitions of pure substances, physical mixtures, and chemical compounds:

1. "created through a reaction that changes the properties of the elements"

Chemical compounds are formed when elements chemically react, and their properties differ from the elements. So this matches c. chemical compounds.

2. "examples: oxygen, aluminum, gold"

Oxygen (element), aluminum (element), and gold (element) are pure substances (elements are a type of pure substance). So this matches a. pure substances.

3. "mixed in any proportion"

Physical mixtures (like solutions, suspensions) can have components mixed in any ratio (e.g., different amounts of salt in water). So this matches b. physical mixtures.

4. "examples: salt water, pure air, concrete, powders"

These are mixtures (salt water is a solution, air is a gas mixture, concrete/powders are heterogeneous mixtures). So this matches b. physical mixtures.

5. "examples: water (H₂O), salt (NaCl), ammonia"

These are compounds (formed by chemical bonding of elements, with fixed composition). So this matches c. chemical compounds.

6. "composition does not vary"

Pure substances (elements or compounds) have a fixed, unchanging composition. So this matches a. pure substances.

Final Matches:

1. c. chemical compounds
2. a. pure substances
3. b. physical mixtures
4. b. physical mixtures
5. c. chemical compounds
6. a. pure substances

(Note: If the question expects one answer per blank, list them in order as: c, a, b, b, c, a)