Question

A chemist performs the same tests on two homogeneous white

crystalline solids, A and B. The results are shown in the table below.
Solid A
Solid B
Crystalline
Crystalling and Powdery
Appearance and
Texture
35.7
10.5
Solubility in Water
g per 100 mL H.O at 0°C
Good Conductor
Okay Conductor
Conductivity
(Yes/No)
The results of these test suggest that:
A. both solids only contain ionic bonds
B. both solids only contain Covalent bonds
C. Solid A contains only lonic bonds and solid B only contains Covalent bonds
D. Solid A contains only Covalent bonds and solid B contains only lonic bonds
E. One Solid contains only one type of bond and the other contains both types
of bonds

Answer 1

Substance A with its ductility and conductivity is likely a metallic solid. Substance B's brittleness and conductivity when molten suggest an ionic solid. Substance C's hardness and non-conductivity match a covalent network solid, while Substance D's softness and non-conductivity indicate a molecular solid.

Step-by-step explanation:

Classes of crystalline solids provide critical information regarding the properties of materials, which are deeply influenced by the types of chemical bonding they exhibit. Solids can be broadly categorized into four types: ionic, metallic, covalent network, and molecular solids. These solid types have characteristic physical properties. Here we'll match properties to solid types.

• Substance A, which is ductile and a good conductor of electricity, is likely a metallic solid because of the properties of malleability and conductivity.
• Substance B, which is brittle and conducts electricity when molten, can be considered an ionic solid. Ionic solids are generally poor conductors in solid form but conduct when liquid.
• Substance C, known for being very hard and non-conductive, fits the typical properties of covalent network solids.
• Substance D, described as soft and non-conductive, is characteristic of a molecular solid with weak intermolecular forces.

These substances' physical properties like electrical conductivity, state of matter, and solubility in water provide hints regarding the predominant types of chemical bonding present in each material, leading to the identification of the solid type.

Answer 2

The correct answer to whether the two solids A and B contain ionic or covalent bonds is Option E: One Solid contains only one type of bond and the other contains both types of bonds, as Solid A is likely ionic due to its high solubility and conductivity, while Solid B could contain a mix of ionic and covalent bonds.

Step-by-step explanation:

The given information describes two homogeneous white crystalline solids, A and B, with different properties. The solubility in water, appearance, texture, and conductivity have been provided to determine the bonding types present in each solid. Based on their characteristics, we can infer the types of bonds in crystalline substances. Ionic compounds typically form hard crystalline structures, are soluble in water, and are able to conduct electricity when molten or dissolved due to the movement of ions. Covalent molecular compounds usually have lower melting points and are poor conductors of electricity in both solid and liquid forms due to the discrete molecules held together by weak intermolecular forces.

Solid A has a solubility of 35.7 g per 100 mL H2O at 0°C and is a good conductor, which indicates that it is likely composed of ionic bonds. Solid B, with a solubility of 10.5 g per 100 mL H2O at 0°C and being an okay conductor, might also include ionic bonds but perhaps to a lesser extent than solid A or includes a larger proportion of covalent bonds. It's tricky to determine the precise nature of the bonds in Solid B based on the given information alone. However, the details point towards Solid A containing only ionic bonds, while Solid B could contain a mix of ionic and covalent bonds.

Therefore, the correct answer to the student's question is Option E: One Solid contains only one type of bond and the other contains both types of bonds.