1.Which of these substances has bent molecular geometry around the oxygen atom? Multiple correct answer may apply.
a.water
b.isopropyl alcohol (rubbing alcohol)**
c.acetone**
d.diethyl ether.
2.Which of these species are polar? Ignore slightly polar C-H bonds. Multiple correct answers may apply.
a.water **
b.isopropyl alcohol (rubbing alcohol)
c.acetone **
d.diethyl ether.
3.Which of these substances has the ability to hydrogen bond to itself Multiple correct answer may apply.
a.water **
b.isopropyl alcohol (rubbing alcohol)
c.acetone **
d.diethyl ether.
4.At a temperature of 35.0 ºC, 19.3 kJ of thermal energy will make 33.0 g of acetone evaporate. Calculate the heat of vaporization of acetone at 35.0 ºC in units of kJ/mol.
I am confused on how to use the equation.
Please check my answers for the other ones.....There my be more than one answer.
I may not be much help here because I'm confused on some of the questions. So take my help as advice and look for other sources.
#1.
I know what bent means. Water, which you have checked, is correct. But all of the organic molecules below water are bent also, in the sense that none of them are linear compounds. I would check all of them but I don't think that is the spirit of the question.
#2.
Water, which you have checked, certainly is polar and that answer is correct. But then the questioner says we are to ignore the polarity between bonds such as C-H and the confusion begins again. How much is too much to ignore. In my opinion, all of them are polar; they all have a dipole moment.
#3.
Water and isopropyl alcohol can form hydrogen bonds. It is true that both acetone and diethyl ether have the very negative C=O structure; however, there is no hydrogen attached directly to them. There may be some slight tendencies to form H bonding with the H attached to the C atoms but this is weak. I think most organic chemists will say that diethyl ether and acetone do not form H bonds.
#4.
It would have been helpful if you had shown what formula you don't know how to use.
q = mass x delt H vap.
You are given q, which I would leave in kJ. You are given mass in grams, that should be changed to moles of acetone. Solve for delta H vap. I hope this helps.
Sure! Let's go through each question and explain how to get the answer.
1. Which of these substances has bent molecular geometry around the oxygen atom? (Multiple correct answers may apply.)
To determine the molecular geometry of a molecule, you need to examine the arrangement of its atoms and lone pairs. Bent molecular geometry occurs when a central atom (in this case, oxygen) is bonded to two other atoms and has one or two lone pairs of electrons.
a) Water (H2O): Water has bent molecular geometry because the oxygen atom is bonded to two hydrogen atoms and has two lone pairs of electrons.
b) Isopropyl alcohol (rubbing alcohol): Isopropyl alcohol also has bent molecular geometry, as the oxygen atom is bonded to three carbon atoms and has a lone pair of electrons.
c) Acetone: Acetone has a trigonal planar molecular geometry, not bent.
d) Diethyl ether: Diethyl ether also has a bent molecular geometry, as the oxygen atom is bonded to two carbon atoms and has two lone pairs of electrons.
Based on this information, both b) isopropyl alcohol and d) diethyl ether have bent molecular geometry around the oxygen atom.
2. Which of these species are polar? (Multiple correct answers may apply.)
To determine if a molecule is polar or not, you need to consider its molecular geometry and the polarity of its bonds. Polar molecules have an uneven distribution of charge due to electronegativity differences between atoms.
a) Water (H2O): Water is a polar molecule due to its bent molecular geometry and the presence of polar O-H bonds.
b) Isopropyl alcohol (rubbing alcohol): Isopropyl alcohol is also a polar molecule because it has a bent molecular geometry and polar O-H bonds.
c) Acetone: Acetone is a polar molecule due to its trigonal planar molecular geometry and the presence of a polar C=O (carbon-oxygen) bond.
d) Diethyl ether: Diethyl ether is a nonpolar molecule because it has a bent molecular geometry, but its bonds (C-O-C) are nonpolar.
Based on this information, a) water, b) isopropyl alcohol, and c) acetone are all polar.
3. Which of these substances has the ability to hydrogen bond to itself? (Multiple correct answers may apply.)
Hydrogen bonding occurs when a hydrogen atom bonded to a highly electronegative atom (such as oxygen or nitrogen) interacts with another electronegative atom in a neighboring molecule.
a) Water (H2O): Water has the ability to form hydrogen bonds with other water molecules due to the electronegative oxygen atom and the partially positive hydrogen atoms.
b) Isopropyl alcohol (rubbing alcohol): Isopropyl alcohol can form hydrogen bonds with other isopropyl alcohol molecules as it contains an OH group.
c) Acetone: Acetone does not have a hydrogen atom bonded to an electronegative atom, so it cannot form hydrogen bonds with itself.
d) Diethyl ether: Diethyl ether also does not have any hydrogen atoms bonded to electronegative atoms, so it cannot form hydrogen bonds with itself.
Based on this information, a) water and b) isopropyl alcohol have the ability to hydrogen bond to themselves.
4. At a temperature of 35.0 ºC, 19.3 kJ of thermal energy will make 33.0 g of acetone evaporate. Calculate the heat of vaporization of acetone at 35.0 ºC in units of kJ/mol.
To calculate the heat of vaporization (ΔHvap) of acetone, you need to use the equation:
ΔHvap = q/m
Where:
- ΔHvap is the heat of vaporization (unknown)
- q is the thermal energy required (given as 19.3 kJ)
- m is the mass of the substance (given as 33.0 g)
First, convert the mass of acetone from grams to moles using its molar mass (58.08 g/mol):
moles = mass / molar mass
moles = 33.0 g / 58.08 g/mol ≈ 0.5686 mol
Now, substitute the given values into the equation:
ΔHvap = 19.3 kJ / 0.5686 mol ≈ 34.00 kJ/mol
Therefore, the heat of vaporization of acetone at 35.0 ºC is approximately 34.00 kJ/mol.