How much heat ,in joules,is needed to vaporize and 18.0 gram sample of water at 100°
1 answer:
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To solve the question we will assume that the gas behaves like an ideal gas, that is to say, that there is no interaction between the molecules. Assuming ideal gas we can apply the following equation:
Where,
P is the pressure of the gas
V is the volume of the gas
n is the number of moles
R is a constant
T is the temperature
Now, we have two states, an initial state, and a final state. The conditions for each state will be.
Initial state (1)
P1=975Torr=1.28atm
V1=3.8L
T1=-18°C=255.15K
Final state(2), STP conditions
P2=1atm
T2=273.15K
V2=?
We will assume that the number of moles remains constant, so the nR term of the first equation will be constant. For each state, we will have:
Since nR is the same for both states, we can equate the equations and solve for V2:
We replace the known values:
At STP conditions the gas would occupy 5.2L. First option
Answer:
Explanation:
For each of these molecules, you must determine their VSEPR structure and then identify the strongest intermolecular forces.
Remember that water is a highly polar molecule.
a) CH₄
Electron geometry: tetrahedral
Molecular geometry: tetrahedral
Bond polarity: C-H bond nonpolar
Molecular polarity: nonpolar
Strongest IMF: London dispersion forces
Solubility in water: low
A nonpolar molecule is insoluble in a polar solvent.
b) CCl₄
Electron geometry: tetrahedral
Molecular geometry: tetrahedral
Bond polarity: C-Cl bond nonpolar
Molecular polarity: nonpolar (symmetrical molecule. All bond dipoles cancel)
Strongest IMF: London dispersion forces
Solubility in water: low
A nonpolar molecule is insoluble in a polar solvent.
d) PH₃
Electron geometry: tetrahedral
Molecular geometry: trigonal pyramidal
Bond polarity: P-H bonds are polar
Molecular polarity: polar (all P-H bond dipoles point towards P)
Strongest IMF: dipole-dipole
Solubility in water: soluble
A polar molecule is soluble in a polar solvent.
c) NH₃
Electron geometry: tetrahedral
Molecular geometry: trigonal pyramidal
Bond polarity: N-H bonds are highly polar
Molecular polarity: highly polar (all N-H bond dipoles point towards N)
Strongest IMF: hydrogen bonding
Solubility in water: highly soluble
NH₃ is so polar that it can form hydrogen bonds with water.
