Question

Silver and gold have very similar atomic radii, making them easy to alloy. silver has a higher electronegativity than copper, making the alloy tougher. copper has a smaller radius than silver, disturbing the crystal structure and making the alloy harder. copper and gold do not have any oxidation states in common, making the alloy much softer.Two alloys of silver were created with equal amounts of silver alloyed with either gold or copper. If silver/copper alloy is harder than the silver/gold alloy, which of the following would best explain the difference based on the table above.

Silver has a higher electronegativity than copper, making the alloy tougher.
Copper has a smaller radius than silver, disturbing the crystal structure and making the alloy harder.
Silver and gold have very similar atomic radii, making them easy to alloy.
Copper and gold do not have any oxidation states in common, making the alloy much softer.
1-Butanol (CH₃CH₂CH₂CH₂OH) would be expected to have a higher boiling temperature than 1-propanol (CH₃CH₂CH₂OH) because
a. its hydrogen bonding is stronger.
b. its longer carbon chain and greater number of electrons result in more London dispersion forces.
c. it has a higher molar mass.
d. it is a less polar molecule.

Answer 1

The best explanation for why the silver/copper alloy is harder than the silver/gold alloy, based on the information given, is:

- Copper has a smaller radius than silver, disturbing the crystal structure and making the alloy harder.

Regarding the boiling temperature of 1-butanol (CH₃CH₂CH₂CH₂OH) compared to 1-propanol (CH₃CH₂CH₂OH), the correct explanation is:

- It has a higher molar mass. The correct answer is option C.

The best explanation for why the silver/copper alloy is harder than the silver/gold alloy, based on the information given, is:

- Copper has a smaller radius than silver, disturbing the crystal structure and making the alloy harder.

When silver is alloyed with copper, the smaller copper atoms disrupt the crystal structure of the alloy, making it harder. This distortion of the crystal structure creates more obstacles for dislocations to move through the material, increasing its hardness. On the other hand, silver and gold have very similar atomic radii, so when silver is alloyed with gold, the crystal structure remains relatively undisturbed, resulting in a softer alloy.

Regarding the boiling temperature of 1-butanol (CH₃CH₂CH₂CH₂OH) compared to 1-propanol (CH₃CH₂CH₂OH), the correct explanation is:

- It has a higher molar mass.

The boiling temperature of a substance is influenced by several factors, including intermolecular forces and molar mass. In this case, 1-butanol has a longer carbon chain and higher molar mass than 1-propanol. The longer carbon chain increases the number of London dispersion forces between molecules, which require more energy to break and thus result in a higher boiling temperature. Additionally, 1-butanol can form hydrogen bonds due to the presence of the -OH group, further increasing the boiling temperature. Therefore, the higher molar mass of 1-butanol is the primary reason for its higher boiling temperature compared to 1-propanol.