Answer:
Choice B. The solid with hydrogen bonding.
Assumption: the molecules in the four choices are of similar sizes.
Explanation:
Molecules in a molecular solid are held intact with intermolecular forces. To melt the solid, it is necessary to overcome these forces. The stronger the intermolecular forces, the more energy will be required to overcome these attractions and melt the solid. That corresponds to a high melting point.
For molecules of similar sizes,
- The strength of hydrogen bonding will be stronger than the strength of dipole-dipole attractions.
- The strength of dipole-dipole attractions (also known as permanent dipole) will be stronger than the strength of the induced dipole attractions (also known as London Dispersion Forces.)
That is:
Strength of Hydrogen bond > Strength of Dipole-dipole attractions > Strength of Induced dipole attractions.
Accordingly,
Melting point due to Hydrogen bond > Melting point due to Dipole-dipole attractions > Melting point due to Induced Dipole attractions.
- Induced dipole is possible between all molecules.
- Dipole-dipole force is possible only between polar molecules.
- Hydrogen bonds are possible only in molecules that contain
atoms that are bonded directly to atoms of
,
, or
.
As a result, induced dipoles are the only force possible between molecules of the solid in choice C. Assume that the molecules are of similar sizes, such that the strengths of induced dipole are similar for these molecules.
Melting point in choice B > Melting point in choice D > Melting point in choice A and C.
Add more solvent to decrease the concentration.
Balanced chemical equation for the reaction is:
2S
(g) +
(g)+ 2
O (l) ⇒
Moles of
formed is 5.75 moles.
Moles of oxygen used is 5.75 moles in the reaction.
Explanation:
Data given:
moles of S
= 11.5 moles
moles of
= ?
Moles of
needed =?
balanced equation with states of matter =?
Balanced chemical reaction under STP condition is given as:
2S
(g) +
(g) + 2
O (l) ⇒
From the balanced reaction 2 moles of sulphur dioxide reacted to form 1 mole of sulphuric acid:
so, from 11.5 moles of S
, x moles of
is formed

2x = 11.5
x = 5.75 moles of sulphuric acid formed.
From the balanced reaction 1 mole of oxygen reacted to form 1 mole of sulphuric acid.
when 11.5 moles of Sulphur dioxide reacted then oxygen in the reaction is 5.75 moles.
Answer:
a) The work done is 10.0777 kJ
b) The water's change in internal energy is -122.1973 kJ
Explanation:
Given data:
1 mol of liquid water
T₁ = temperature = 100.9°C
P = pressure = 1 atm
Endothermic reaction
T₂ = temperature = 100°C
1 mol of water vapor
VL = volume of liquid water = 18.8 mL = 0.0188 L
VG = volume of water vapor = 30.62 L
3.25 moles of liquid water vaporizes
Q = heat added to the system = -40.7 kJ
Questions: a) Calculate the work done on or by the system, W = ?
b) Calculate the water's change in internal energy, ΔU = ?
Heat for 3.25 moles:

The work done:

The change in internal energy:
