C 10: Chemical Bonding
Which of these is LEAST electronegative:
nickel, chlorine, fluorine, or oxygen?
nickel
Convert 3.04 atm to units of torr.
2310 torr
How much energy is needed to melt 292 g of ice that is at zero Celsius? (Heat of fusion for water is 6.02 kJ/mol).
97.5 kJ
Suppose a sample gas is a mixture of 63 mL of N2 and 37 mL of O2. Prepare a proper label for this air sample in the following format: ___% __ / __ N2 where you insert numbers and units in the appropriate slots.
63% v/v N2
True or false: For hydrogen bonding to be possible in a molecule, the molecule must have a hydrogen atom bonded directly to a fluorine, oxygen, or chlorine atom.
False.
Which compound below is held together by a COVALENT bond? (use a Periodic Table):
CdBr2 RbCl PO5 Li2SO4
PO5
A sample of gas occupies 7.05 L at a temperature of 20 °C. What will be the new volume of the gas at 100. °C? (pressure remains constant)
8.97 L
What will have a higher boiling point, O2 or HF?
Be prepared to show Lewis structures.
HF (why?)
Which solution would have a higher boiling point, 1 molal KI or 1 molal SrBr2? Which solution of these would have the lowest freezing point?
The 1 molal SrBr2 will have both higher boiling point and lower freezing point.
Define boiling point.
The temperature at which vapor pressure of a liquid equals atmospheric pressure.
True or false: a molecule of the compound H2S would have linear molecular geometry.
Draw a Lewis Structure before answering.
FALSE. What would its molecular geometry be instead?
Which of the following gases is most dense?
helium krypton xenon
xenon
Does water boil at a higher or lower temperature in a valley?
Higher.
All ionic compounds exist in lattices, and the lattice must be “torn apart” when water dissolves them. Which ionic compound do you think would be LEAST soluble in water, NaCl or MgS, and why?
MgS because its lattice is held together by +2 and -2 opposite charges, making for a stronger lattice
Solid A and Solid B are each dissolved in identical beakers of water. Solution B conducts electricity, while Solution A does not. Which solid was an ionic compound?
Solid B
How many lone pairs does the correct Lewis Structure for hydronium have?
Be prepared to show the Lewis Structure.
One
A 315 mL sample of air is at 754 torr and 31 °C. What volume will this gas occupy at 901 torr and 63 °C?
291 mL
Does NH3 or CF4 have a higher vapor pressure? Why?
Be prepared to show Lewis structures.
CF4 because it only has London Dispersion force, while NH3 has LD force, dipole-dipole, and hydrogen bonding.
How many mL of 15.0 M KOH is needed to prepare a 1000. mL of diluted solution of 5.00 M concentration?
333 mL
A red blood cell (0.9% NaCl) is submerged in a 0.2% NaCl solution. What happens and why?
Hemolysis (the cell bursts) because of osmosis: water flows through the cell's membrane to dilute the higher concentration area. In this case, water flows into the cell until it bursts.
Name the molecular geometry of HBr and determine whether it would have a dipole moment.
Be prepared to show your Lewis Structure.
Linear. There is a dipole moment.
What pressure is exerted by 2.24 mole of a gas that has a volume of 3556 mL at a temperature of 287 K? (Note R=0.0821 L atm / mol K).
14.8 atm
Which substance would be expected to have the highest boiling point? (Draw Lewis structures and consider intermolecular forces.)
Cl2 O2 CO GeO
GeO
Calculate the molarity of a solution made from 135 grams of KBr where you made 4.00 liters of solution.
0.284 M or mol/L
What is the mass percent of a solution prepared by dissolving 23.4 grams of solid into 46.1 grams of water?
33.7%