Bohr's atomic model may have not been the accurate atomic model we have in the present, but he helped paved the way for accurate discoveries. His model is also called the planetary model. The nucleus, containing the neutrons and protons are situated at the center of the atom. The electrons are orbiting around the nucleus. The model is illustrated as shown in the attached picture.
First of all, there are five types of solid materials:
Metallic solids which are solids composed of metal atoms that are held together by metallic bonds.
Network solid is a chemical compound in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material.
Molecular solid is a solid consisting of discrete molecules.
Ionic solid is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding.
Amorphous solid is non-crystalline solid that lacks the long-range order that is characteristic of a crystal.
Now, after the defined all the types of solid materials in the equation lets to solve it.
A. the answer is the network solids, because covalent bonds are relatively strong, covalent are typically characterized by hardness, strength, and high melting points.
B. the answer is the metallic solids, due to that heat conduction occurs when a substance is heated and the particles will gain more energy vibrating more. These molecules then bump into nearby particles and transfer some of their energy to them and in metals this process have a higher probability than in the case of other solids due to the nature of the chemical bonds. It also has a range of hardness due to the strength of metallic bonds which varies dramatically.
C. the answer is the ionic solid; due to positive and negative ions which are bonded to form a crystalline solid held together by charge attractions.
Answer:
Rank the following chemical species from lowest absolute entropy (So) (1) to highest absolute entropy (5) at 298 K?
a. Al (s)
b. H2O (l)
c. HCN (g)
d. CH3COOH (l)
e. C2H6 (g)
Explanation:
Entropy is the measure of the degree of disorderness.
In solids, the entropy is very less compared to liquids and gases.
The entropy order is:
solids<liquids<gases
Among the given substances, water in liquid form has a strong intermolecular H-bond.
So, it has also less entropy.
Next acetic acid.
Between the gases, HCN, and ethane, ethane has more entropy due to very weak intermolecular interactions.
HCN has slight H-bonding in IT.
Hence, the entropy order is:
Al(s) < CH3COOH (l) <H2O(l) < HCN(g) < C2H6(g)
Answer:
Total Ionic equation:
H⁺(aq) + NO₃⁻ (aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + NO₃⁻ (aq)
Explanation:
Chemical equation:
HNO₃ + NaOH → NaNO₃ + H₂O
Balanced chemical equation:
HNO₃(aq) + NaOH(aq) → NaNO₃(aq) + H₂O(l)
Total Ionic equation:
H⁺(aq) + NO₃⁻ (aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + NO₃⁻ (aq)
Net ionic equation:
H⁺(aq) + OH⁻(aq) → H₂O(l)
The NO₃⁻ (aq) and Na⁺ (aq) are spectator ions that's why these are not written in net ionic equation. The water can not be splitted into ions because it is present in liquid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation
The law of conservation of mass states that mass is neither created nor destroyed. Since we have 2 g/mol of A and 3 g/mol of B then AB should be equal to the sum of their molar mass that is
2 g/mol + 3 g/mol = 5 g/mol AB
for the case of A2B3
A2 = 2 * 2 = 4 g/mol
B3 = 3 * 3 = 9 g/mol
therefore A2B3 = 13 g/mol
