Chem 2 Test 1 (mastering hw problems)
Ethylene glycol, the primary ingredient in antifreeze, has the chemical formula C2H6O2. The radiator fluid used in most cars is a half-and-half mixture of water and antifreeze. Part A What is the freezing point of radiator fluid that is 50% antifreeze by mass? Kf for water is 1.86 ∘C/m. Express your answer to three significant figures and include the appropriate units.
-29.9 ∘C
Polonium is a radioactive metal that is used as a heat source in space satellites. Polonium has a simple cubic unit cell. How many atoms of Po are present in each unit cell? Express your answer as an integer.
1
Identify each of the labeled points (indicated with letters) or changes (indicated with two letters separated by an arrow) shown on the phase diagram.
1. The point indicated by A is thetriple point. 2. The transition shown by the line from E to F is sublimation. 3. The transition shown by the line from F to E is deposition. 4. The transition shown by the line from D to C is condensation. 5. The transition shown by the line from E to C is melting. 6. The point indicated by B is the critical point. 7. The transition shown by the line from C to D is boiling. 8. The transition shown by the line from C to E isfreezing.
Assuming complete dissociation of the solute, how many grams of KNO3 must be added to 275 mL of water to produce a solution that freezes at −14.5 ∘C? The freezing point for pure water is 0.0 ∘C and Kf is equal to 1.86 ∘C/m. Express your answer to three significant figures and include the appropriate units. Hints
108 g
What is the boiling point of radiator fluid that is 50% antifreeze by mass? Kb for water is 0.512 ∘C/m. Express your answer to one decimal place and include the appropriate units.
108.2 ∘C
PF3Cl2 is a nonpolar molecule. Based on this information, determine the F−P−F bond angle, the Cl−P−Cl bond angle, and the F−P−Cl bond angle. Enter the number of degrees of the F−P−F, Cl−P−Cl, and F−P−Cl bond angles, separated by commas (e.g., 30,45,90) Hints
120,180,90 degrees
A solution was prepared by dissolving 43.0 g of KCl in 225 g of water. Part A Calculate the mass percent of KCl in the solution. Express your answer with the appropriate units. Hints
16.0 %
Vanadium has a body-centered cubic unit cell. How many atoms of V are present in each unit cell? Express your answer as an integer.
2
Calculate the molarity of KCl in the solution if the total volume of the solution is 239 mL. Express your answer with the appropriate units. Hints
2.41 M
Calculate the molality of KCl in the solution. Express your answer with the appropriate units. Hints
2.56 m
How many liters of water are required to dissolve 1.00 g of calcium phosphate? Express your answer in liters to three significant figures.
2.93×104 L
How much heat energy, in kilojoules, is required to convert 43.0 g of ice at −18.0 ∘C to water at 25.0 ∘C ? Express your answer to three significant figures and include the appropriate units.
20.5 kJ
Enter the critical temperature of water.
374 ∘C
Nickel has a face-centered cubic unit cell. How many atoms of Ni are present in each unit cell? Express your answer as an integer
4
How long would it take for 1.50 mol of water at 100.0 ∘C to be converted completely into steam if heat were added at a constant rate of 18.0 J/s ? Express your answer to three significant figures and include the appropriate units.
56.3 min
Ignoring lone-pair effects, what is the smallest bond angle in BrI5? Express your answer as an integer. Hints
90 degrees
What atoms must a molecule contain to participate in hydrogen bonding with other molecules of the same kind?
A HYDROGEN ATOM MUST BE DIRECTLY ATTACHED TO F, O, or N
Acetone, H3CCOCH3, has a boiling point of 56∘C. Based on the data given in the figure, would you expect acetone to have a higher or lower vapor pressure than ethanol at 25∘C?
Acetone has a higher vapor pressure
Which interactions and processes contribute to the dissolution of ionic compounds in water? Check all that apply.
Affinity of hydrogen towards anions Ion-dipole interactions Affinity of oxygen towards cations Hydration
Of the molecules AlCl3 and AlBr3, which has bonds that are more polar?
AlCl3
Explain your answer to part B in terms of intermolecular forces.
Boiling point increases as the strength of intermolecular forces increases
which member in each pair has the stronger IMF dispersion forces? Br2 or O2.
Br2
which member in each pair has the stronger IMF dispersion forces?CH3CH2CH2CH2SH or CH3CH2CH2CH2CH2SH. CH3CH2CH2CH2SH CH3CH2CH2CH2CH2SH
CH3CH2CH2CH2CH2SH
which member in each pair has the stronger IMF dispersion forces?CH3CH2CH2Cl or (CH3)2CHCl? CH3CH2CH2Cl (CH3)2CHCl
CH3CH2CH2Cl
What are the major factors responsible for the difference in boiling points of the two ethers?
CH3OCH2CH2OCH3 is a larger, more polarizable molecule with stronger London-dispersion forces.
Place the following substances in order of decreasing volatility: CH4, CBr4, CH2Cl2, CH3Cl, CHBr3, and CH2Br2.
CH4 CH3Cl CH2Cl2 CH2Br2 CHBr3 CBr4
CHCl3 (61 ∘C) and CHBr3 (150 ∘C), CHBr3 has the higher boiling point because hydrogen bonding is stronger than dipole-dipole forces. CHCl3 has the lower boiling point because hydrogen bonding is weaker than dipole-dipole forces. CHBr3 has the higher boiling point because it has the higher molar mass, which leads to greater polarizability and stronger dispersion forces. CHBr3 has the higher boiling point because CHBr3 molecules are less polar.
CHBr3 has the higher boiling point because it has the higher molar mass, which leads to greater polarizability and stronger dispersion forces.
Classify each solid as a covalent, ionic, metallic, or molecular solid. Drag the appropriate items to their respective bins. Hints
Covalent red phosphorus Ionic calcium fluoride Metallic pure calcium Molecular( usually those at freezing) frozen ethanol
Which type (or types) of crystalline solid is characterized by each of the following. Drag the appropriate items to their respective bins.
Covalent network or ionic High melting point and poor electrical conductivity Molecular or metallic Softness and relatively low melting point Metallic only High mobility of electrons throughout the solid Covalent network only Network of covalent bonds Ionic only Charged particles throughout the solid
Which statement best describes the polarity of SCl4I2?
Depending on the arrangement of outer atoms, this molecule could be polar or nonpolar.
You are a researcher for a golf club manufacturer. You are given two identical looking cubes of a metal alloy. You are informed that they are made of the exact same material, but one is crystalline, whereas the other is amorphous. It is your job to determine which one is amorphous because this one is more stress-resistant and is useful in reinforcing golf clubs. Which of the following is the best way to determine which is which?
Determine the density of each cube. The less dense cube is the amorphous solid.
picture d O-S-O
Dipole-dipole forces
What is the predominant intermolecular force in the liquid state of each of these compounds: hydrogen fluoride (HF), methane (CH4), and methyl chloride (CH3Cl)?
Dipole-dipole forces CH3Cl Hydrogen bonding HFDispersion forces CH4
Classify each process as an endothermic or exothermic process.forming solute-solvent attractions breaking solute-solute attractions, breaking solvent-solvent attractions
Exothermic forming solute-solvent attractions Endothermic breaking solute-solute attractions, breaking solvent-solvent attractions
In the molecule FI, which atom is the negative pole?
F
Predict which of the four interactions is the weakest
Forces on the picture (b
Based on the type or types of intermolecular forces, predict the substance in each pair that has the higher boiling point.
Given the molecules diethyl ether (CH3CH2OCH2CH3) and 1-butanol (CH3CH2CH2CH2OH), 1-butanol (CH3CH2CH2CH2OH) has the higher boiling point mainly due to hydrogen bonding influences. Given the molecules propane (C3H8) and n-butane (C4H10), n-butane (C4H10) has the higher boiling point mainly due to its greater molar mass.
Based on the type or types of intermolecular forces, predict the substance in each pair that has the higher boiling point.
Given the molecules phosgene (Cl2CO) and formaldehyde (H2CO), phosgene (Cl2CO) has the higher boiling point mainly due to its greater molar mass and stronger dispersion forces. Given the molecules sulfur dioxide (SO2) and sulfur trioxide (SO3), sulfur trioxide (SO3) has the higher boiling point mainly due to its greater molar mass and stronger dispersion forces.
Consider equal volumes (say 1 L) of a given substance in the solid, liquid, and gas phases. Arrange them in order of decreasing mass based on the trend for the average substance. If the mass difference between samples is relatively small (10% or less), rank the items as equivalent.
Greatest mass 1 L of substance in the solid phase1 L of substance in the liquid phase Least mass 1 L of substance in the gas phase
What kind of intermolecular attractive force is shown in each of the following cases?
H-F hydrogen bond
HF (20 ∘C) and HCl (-85 ∘C), HF has the higher boiling point because of ionic bonding. HF has the higher boiling point because hydrogen bonding is stronger than dipole-dipole forces. HF has the higher boiling point because hydrogen bonding is weaker than dipole-dipole forces. HF has the higher boiling point because HF molecules are more polar.
HF has the higher boiling point because hydrogen bonding is stronger than dipole-dipole forces.
How do the boiling points vary through this series?
High->low CBr4 CHBr3 CH2Br2 CH2Cl2 CH3Cl CH4
Arrange the following aqueous solutions, each 10% by mass in solute, in order of decreasing boiling point: glucose (C6H12O6), sucrose (C12H22O11), sodium nitrate (NaNO3)
Highest boiling point sodium nitrate glucose sucrose
The freezing points of three solutions of glucose in water are shown below. Arrange the solutions in order of decreasing molal concentration. −1.45 ∘C −5.96 ∘C −3.04 ∘C Rank from highest to lowest molal concentration. To rank items as equivalent, overlap them.
Highest concentration Solution B Solution C Solution A
Arrange the liquids pentane (CH3CH2CH2CH2CH3), pentanol (CH3CH2CH2CH2CH2OH), and pentanal (CH3CH2CH2CH2CHO) in order of decreasing viscosity, surface tension, and boiling point.
Highest viscosity, surface tension, and boiling point pentanol pentanal pentane
Correctly classify each of the following compounds as highly soluble or as either slightly soluble or insoluble in water. Drag the appropriate compounds to their respective bins.
Highly Soluble sodium chloride,potassium hydroxide, ethanol,acetic acid,methanol,sodium sulfate,potassium nitrate Slightly soluble or insoluble hexanol, trichloromethaneC6H6C6H14, carbon tetrachloride,dichloromethane
Indicate the principal type of solute-solvent interaction in each of the following solutions. Drag the appropriate items to their respective bins.
Hydrogen bonding methanol (CH3OH) in water Ion-dipole interactions KCl in water London dispersion forces CH2Cl2 in benzene (C6H6)
Br2 (59 ∘C) and ICl (97 ∘C). Br2 has the lower boiling point because of strong dispersion forces. ICl has the higher boiling point because it is a polar molecule. ICl has the higher boiling point because of ion-dipole-bounds. ICl has the higher boiling point because of weak dispersion forces
ICl has the higher boiling point because it is a polar molecule.
Classify the bonds formed between each pair of elements based on electronegativity values in the following table:
Ionic Be and FSc and O Polar covalent H and BrBe and ClS and O Nonpolar covalent S and IH and P
Consider the following element combinations. Classify the bonds formed between each pair as ionic, polar covalent, or nonpolar covalent qualitatively based solely on each element's position on the periodic table. Do not conduct calculations.
Ionic Cu and ClNa and NFe and O Polar covalent S and Cl O and F P and I Nonpolar covalent I and IP and P
Does the molality of the solution change with the change in temperature? why or why not? yes no
NO;Molality is temperature independent, in other words, molality of solution does not change with the temperature of a solution. Molality is the ratio of moles to mass. Since mass is the same at any given temperature, molality will not change with change in temperature.
Which of the following compounds has the highest boiling point? Hints Br2 NaBr HBr BrF
NaBr
Estimate the external pressure at which diethyl ether will boil at 40 ∘C. Express your answer using three significant figures.
P = 1000 torr
Estimate the external pressure at which ethanol will boil at 60∘C. Express your answer using two significant figures.
P = 340 torr
The approximate vapor pressure of CS2 at 30 ∘C. Express your answer using three significant figures.
P = 385 mmHg
If 0.140 mol of a nonvolatile nonelectrolyte are dissolved in 3.70 mol of water, what is the vapor pressure PH2O of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 ∘C . Express your answer with the appropriate units.
PH2O = 22.9 torr
A solution is composed of 1.60 mol cyclohexane (P∘cy=97.6 torr) and 2.70 mol acetone (P∘ac=229.5 torr). What is the total vapor pressure Ptotal above this solution? Express your answer with the appropriate units.
Ptotal = 180 torr
How much heat is required to convert 34.5 g of ethanol at 30 ∘C to the vapor phase at 78 ∘C? Express your answer using two significant figures.
Q = 33 kJ
How much heat is required to convert 34.5 g of ethanol at -168 ∘C to the vapor phase at 78 ∘C? Express your answer using two significant figures.
Q = 50 kJ
Calculate the heat required to convert 38.5 g of C2Cl3F3 from a liquid at 11.95 ∘C to a gas at 95.80 ∘C. Express your answer using two significant figures.
Q = 8.1 kJ
Match each description to the appropriate phase of matter.
Solid a substance with a fixed volume and fixed shape Liquid a substance with a fixed volume and no fixed shape Gas a substance with no fixed volume or shape
Classify each property as associated with a liquid that has strong or weak intermolecular forces. Drag the appropriate items to their respective bins.
Strong intermolecular forces high viscositylow vapor pressurehigh boiling pointhigh surface tension Weak intermolecular forces low boiling pointhigh vapor pressurelow surface tensionlow viscosity
Rank the solutions from strongest to weakest solute-solvent interaction. Rank the items in order of decreasing of solute-solvent interaction strength.
Strongest interaction KCl in water methanol (CH3OH) in water CH2Cl2 in benzene (C6H6)
Estimate the boiling point of diethyl ether at 400 torr. Express your answer using two significant figures.
T = 17 ∘C
The temperature at which the vapor pressure equals 300 torr. Express your answer using two significant figures.
T = 22 ∘C
Use the vapor-pressure curve in the figure to estimate the boiling point of ethanol at an external pressure of 200 torr. Express your answer using two significant figures.
T = 48 ∘C
What is the boiling point of water at an elevation of 1.25×104 ft ? Express your answer with the appropriate units using three significant figures. Hints
T = 87.6 ∘C
The normal boiling point of CS2. Express your answer using two significant figures.
Tbp = 47 ∘C
Sometimes when we heat food in the microwave, the lid of the container pops off. Why does this occur?
The air and water vapor inside the container are expanding
Explain why replacement of a hydrogen on the oxygen by CH3 generally results in a lower boiling point.
The dipole-dipole is being decreased from H-bonding to dispersion forces only,causing a decrease in intermolecular interactions.
List the following aqueous solutions in order of decreasing freezing point: 0.040 m glycerin (C3H8O3), 0.020 m KBr, 0.030 m phenol (C6H5OH). Rank solutions from highest freezing point to lowest freezing point. To rank items as equivalent, overlap them.
The highest freezing point 0.030 m phenol (C6H5OH), 0.040 m glycerin (C3H8O3), 0.020 m KBr,
A dipole moment tends to stabilize the liquid state of the compound as molecules align to form attractive molecular interactions. A liquid state that is more stable, that is one that is held together by stronger dipole forces, will have a higher boiling point since it takes more energy to break these intermolecular forces. Rank the following compounds in order of decreasing boiling point: potassium bromide (KBr), methane (CH4), and iodomethane (CH3I)
The ionic compound KBr has the highest boiling point of the group, at 1435 ∘C. Iodomethane, CH3I, is asymmetric and polar, with a boiling point of 42 ∘C. The symmetric molecule CH4 has no net dipole moment. It is thus nonpolar and has a boiling point of -161 ∘C.
Which statement best describes the polarity of CH2Cl2? Hints
The molecule is always polar.
Which choice best describes the polarity of BrI5? Hints
The molecule is polar and has polar bonds.
When ammonium chloride dissolves in water, the solution becomes colder.Why does the solution form?
The solution forms because the favorable entropy of mixing outweighs the increase in enthalpy by the solution.
Water originally at 100.0∘C and 0.50 atm is cooled at constant pressure until the temperature is -10∘C.
The vapor condenses to the liquid and then the liquid water freezes
Refer to the figure, and describe all the phase changes that would occur in each of the following cases. Water vapor originally at 0.005 atm and -0.5∘C is slowly compressed at constant temperature until the final pressure is 20 atm.
The vapor condenses to the solid (desublimates).
A white substance melts with some decomposition at 730 ∘C. As a solid, it is a nonconductor of electricity, but it dissolves in water to form a conducting solution.
Which type of solid might the substance be? ionic
Calculate the mole fraction of the ionic species KCl in the solution. Express the concentration numerically as a mole fraction in decimal form. Hints
X = 4.41×10−2
As you saw in Part B, the vapor above the cyclohexane-acetone solution is composed of both cyclohexane vapor and acetone vapor. What mole fraction of the vapor above the solution, Xcy(vapor), is cyclohexane? Express your answer numerically. 1
Xcy(vapor) = 0.20
The figure (Figure 1) shows two volumetric flasks containing the same solution at two temperatures.Does the molarity of the solution change with the change in temperature? why or why not? yes no
YES;Molarity is temperature dependent. Molarity is affected by temperature due to the fact that it is based on the volume of a solution, and the volume of a substance is affected by changes in temperature.
Both of the carbon-oxygen double bonds in CO2 are polar. In which direction should the polarity arrows point?
away from the central carbon atom
On moving upward through the atmosphere the pressure will decrease. If we assume that the temperature does not change, what phase change would you expect to see as we move away from the surface?
both vaporization and sublimation
Would you expect stearic acid, CH3(CH2)16COOH, to? be more soluble in water or in carbon tetrachloride? why in water in carbon tetrachloride
carbon tetrechloride;Stearic acid contains a nonpolar group and so does carbon tetrachloride, therefore it will be more soluble in carbon tetrachloride than it will be in water.
Suppose you have two colorless molecular liquids, one boiling at - 84 ∘C, the other at 34 ∘C, and both at atmospheric pressure. Which of the following statements is correct?The higher-boiling liquid has greater total intermolecular forces than the other. correct not correct
correct
Suppose you have two colorless molecular liquids, one boiling at - 84 ∘C, the other at 34 ∘C, and both at atmospheric pressure. Which of the following statements is correct?The two liquids have identical vapor pressures at their normal boiling points. correct not correct
correct
You are given a white substance that sublimes at 3000 ∘C; the solid is a nonconductor of electricity and is insoluble in water.Which type of solid might this substance be? molecular covalent-network ionic metallic
covalent-network
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude? Vapor pressure. increase decrease
decrease
Which would you expect to be more soluble in water, cyclohexane or dioxane? (Figure 1)Why? cyclohexane dioxane
dioxane;Dioxane can form hydrogen bonds with the water molecule and the cyclohexane cannot. Also, they are both polar, and "like dissolves like".
Indicate the type of solute-solvent interaction that should be most important in each of the following solutions. HCl in acetonitrile (CH3CN)
dipole-dipole forces
Indicate the type of solute-solvent interaction that should be most important in each of the following solutions. CCl4 in benzene (C6H6)
dispersion forces
When ammonium chloride dissolves in water, the solution becomes colder.Is the solution process exothermic or endothermic?
endothermic
In terms of the total attractive forces for a given substance dipole-dipole interactions, when present, are always larger than dispersion forces.
f
For the noble gases the dispersion forces decrease while the boiling points increase as you go down the column in the periodic table.
false
Rank the crystal lattice structures in order of decreasing efficiency of space in the structure. Rank from most to least efficient use of space. To rank items as equivalent, overlap them.
hexagonal, close packing.face-centered cubic body-centered cubic,simple cubic
Indicate the type of solute-solvent interaction that should be most important in each of the following solutions. methanol (CH3OH) in water
hydrogen bonding
If the 3.90 m solution from Part A boils at 103.45 ∘C, what is the actual value of the van't Hoff factor, i? The boiling point of pure water is 100.00 ∘C and Kb is equal to 0.512 ∘C/m. Express your answer numerically. Hints
i = 1.73
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Boiling point.
increase
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Critical temperature. increase decrease
increase
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Freezing point. increase decrease
increase
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Heat of vaporization. increase decrease
increase
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Surface tension. increase decrease
increase
As the intermolecular attractive forces between molecules increase in magnitude, do you expect each of the following to increase or decrease in magnitude?Viscosity. increase decrease
increase
At 10 ∘C and 1 atm carbon dioxide is in the gas phase. From these conditions, how could the gaseous CO2 be converted into liquid CO2?
increase the pressure.
picture c Na+ -H2O
ion-dipole
Indicate the type of solute-solvent interaction that should be most important in each of the following solutions. KBr in water
ion-dipole forces
In what state would you expect to find methane on the surface of Titan?
liquid
At 100 ∘C and 1 atm, water is in which phase?
liquid-gas equilibrium
Does the following diagram best describe a crystalline solid, a liquid, or a gas?
liquid;The above diagram best describes a liquid. In the diagram,the particles are close together, mostly touching, but have no regular arrangement or order to them. If this were a gaseous diagram, the particles would be far apart. Also, if this were a crystalline solid diagram, it would have regular (or more definite) repeating structure in all directions.
picture b F-F
london dispersion
A solution of water (Kf=1.86 ∘C/m) and glucose freezes at − 4.35 ∘C. What is the molal concentration of glucose in this solution? Assume that the freezing point of pure water is 0.00 ∘C. Express your answer to three significant figures and include the appropriate units. Hints
m = 2.34 molal
What mass of this substance must evaporate to freeze 210 g of water initially at 15 ∘C? (The heat of fusion of water is 334 J/g; the specific heat of water is 4.18 J/(g⋅K).) Express the mass in grams to two significant digits.
m = 290 g
A solution of water (Kb=0.512 ∘C/m) and glucose boils at 102.06 ∘C. What is the molal concentration of glucose in this solution? Assume that the boiling point of pure water is 100.00 ∘C. Express your answer to three significant figures and include the appropriate units.
m = 4.02 molal
A 2.050×10−2 M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.4 mL . The density of water at 20.0∘C is 0.9982 g/mL. Part A Calculate the molality of the salt solution. Express your answer to four significant figures and include the appropriate units.
mNaCl = 2.055×10−2 molkg
Rank the following substances in order from most soluble in water to least soluble in water: ethane, C2H6; 1-pentanol, C5H11OH; magnesium chloride, MgCl2; and propane, C3H8. Rank from most to least soluble in water. To rank items as equivalent, overlap them.
magnesium chloride 1-pentanol propane ethane
Ascorbic acid (vitamin C, C6H8O6) is a water-soluble vitamin. A solution containing 80.0 g of ascorbic acid dissolved in 220 g of water has a density of 1.22 g/mL at 55∘C.Calculate the mass percentage of ascorbic acid in this solution. Express the mass percentage to three significant digits.
mass percent = 26.7 %
Classify each of the following materials as metal, semiconductor, or insulator: (a) InAs (b) MgO (c) HgS (d) Sn.
metal Sn semiconductor InAs,HgS insulator MgO
Ascorbic acid (vitamin C, C6H8O6) is a water-soluble vitamin. A solution containing 80.0 g of ascorbic acid dissolved in 220 g of water has a density of 1.22 g/mL at 55∘C.Calculate the molality of ascorbic acid in this solution. Express the molality in moles per kilogram to three significant digits.
molality = 2.06 mol/kg
Ascorbic acid (vitamin C, C6H8O6) is a water-soluble vitamin. A solution containing 80.0 g of ascorbic acid dissolved in 220 g of water has a density of 1.22 g/mL at 55∘C.Calculate the molarity of ascorbic acid in this solution. Express the molarity to three significant digits.
molarity = 1.85 M
Can the CH3Br molecule form hydrogen bonds with other molecules of the same kind?
n
Can the CH3F molecule form hydrogen bonds with other molecules of the same kind?
no
What is the normal boiling point of this compound? Express your answer as an integer and include the appropriate units.
normal boiling point = 100 ∘C
Suppose you have two colorless molecular liquids, one boiling at - 84 ∘C, the other at 34 ∘C, and both at atmospheric pressure. Which of the following statements is correct?At -84 ∘C both liquids have vapor pressures of 760 mmHg. correct not correct
not correct
Suppose you have two colorless molecular liquids, one boiling at - 84 ∘C, the other at 34 ∘C, and both at atmospheric pressure. Which of the following statements is correct?The lower boiling liquid must consist of nonpolar molecules. correct not correct
not correct
Suppose you have two colorless molecular liquids, one boiling at - 84 ∘C, the other at 34 ∘C, and both at atmospheric pressure. Which of the following statements is correct?The lower-boiling liquid has a lower molecular weight than the higher-boiling liquid. correct not correct
not correct
What is the electron-domain (charge-cloud) geometry of BrI5? Enter the electron-domain geometry of the molecule. Hints
octahedral
A 2.050×10−2 M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.4 mL . The density of water at 20.0∘C is 0.9982 g/mL. Calculate the concentration of the salt solution in parts per million. Express your answer as an integer to four significant figures and include the appropriate units.
parts per million NaCl = 1200 ppm
A 2.050×10−2 M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.4 mL . The density of water at 20.0∘C is 0.9982 g/mL. Calculate the concentration of the salt solution in percent by mass. Express your answer to four significant figures and include the appropriate units.
percent by mass NaCl = 0.1200 %
The enthalpy of solution for a solid with ΔH values of approximately equal magnitude for each of the steps involved in the solution formation process is __________.
slightly endothermic
At -78 ∘C and 5.2 atm, carbon dioxide is in which phase?
solid
What is the solubility of calcium phosphate in parts per million? Express your answer in parts per million to three significant figures.
solubility = 3.41×10−2 ppm
At 25.0∘C, the molar solubility of calcium phosphate in water is 1.10×10−7 M . Calculate the solubility in grams per liter. Express your answer in grams per liter to three significant figures.
solubility = 3.41×10−5 g/L
What is the molecular geometry of BrI5? Enter the molecular geometry of the molecule. Hints
square pyramidal
All other factors being the same, dispersion forces between linear molecules are greater than dispersion forces between molecules whose shapes are nearly spherical.
t
Water is known as a polar molecule because
the electrons of the covalent bond are not shared equally between the hydrogen and oxygen atoms. the oxygen atom has a greater attraction for electrons than the hydrogen atom does.
For molecules with similar molecular weights, the dispersion forces become stronger as the molecules become more polarizable.
true
Can the CH3OH molecule form hydrogen bonds with other molecules of the same kind?
y
Can the CH3NH2 molecule form hydrogen bonds with other molecules of the same kind?
yes
Ascorbic acid (vitamin C, C6H8O6) is a water-soluble vitamin. A solution containing 80.0 g of ascorbic acid dissolved in 220 g of water has a density of 1.22 g/mL at 55∘C.Calculate the mole fraction of ascorbic acid in this solution. Express the mole fraction to three significant digits.
χ = 3.59×10−2
A 2.050×10−2 M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.4 mL . The density of water at 20.0∘C is 0.9982 g/mL. Calculate the mole fraction of salt in this solution. Express the mole fraction to four significant figures.
χNaCl = 3.699×10−4
