Chem Exam 3 Chapter 7,8,9
What is the pH of stomach acid? Enter your answer as a number with a single digit only.
1
Calculate the pH of a solution with H3}O^{+}= 1.8 x 10^{ -4}M.
3.74
What is another use for salt?
Use on snowy roads.
Avogadro's Law is expressed as:
V=n
What is 1 atm equal to?
What is 1 atm equal to? a. 760 mm Hg b .14.7 psi c. 760 torr d. All of these.
What is the mass percent of a solution which has 27.5 g of ethanol (C2H6O) and 175 mL of water? The density of water is 1.00 g/mL.
13.6 %
What forces exist between I2 molecules?
dispersion forces
Which intermolecular forces are present in all molecules and atoms?
dispersion forces
Which of the following is not a property of bases?
dissolves metals
What is the Bronsted-Lowry definition of a base?
proton accepto
What can contribute to acid rain?
reaction of nonmetal oxides with water
What is the Molarity of Nickel II chloride at 0.500 liters with 1 mole of Nickel II chloride solution?
2 M
What is the tendency of a liquid to minimize its surface area?
surface tension
What caused the tragedy at Lake Nyos?
the release of CO_{2} due to a supersaturated solution
What is the concentration of H_{3}O^{+} in a solution with a pH of 2.00?
0.010 M
How many Liters of a 0.218 M Sodium sulfate solution react with .0253 L of 0.113 M BaCl_{2}? Use the reaction below: BaCl{2}(aq) + Na{2}SO{4}(aq)-> BaSO{4} (s) + 2NaCl(aq)
0.013 L
From prior lab questions, you now have all the values needed to solve for n with the ideal gas law. Use 0.0821 liter-atm/mol K for R. PV=nRT. Solve for n. Answer with a number only using four sig figs. Begin with 0. Numeric Answer:
0.0144
Suppose the balloon full of gas were brought out a cold day (-20 degrees Celsius) and put under 3.5 atm of pressure, what would the new volume be? Answer as a number only (to represent liters) with two sig figs. Begin with 0.0
0.085
What is the pOH of a substance with a pH of 3.61?
10.39
What is the pressure of 760 mm Hg when expressed in units of Pa?
101,325 Pa
How many moles of KCl would be present in 5.5 L of 2.10 M KCl? Enter your answer as a number with four sig figs.
11.55
How many liters of oxygen gas are needed to react with 56.0 L of methane at STP to produce carbon dioxide gas and gaseous water? Given: CH4(G) + 2O2(G) --------> CO2(G) + H20(G)
112 L
An oxygen tank holds 4.5 liters of gas at 305 K. What temperature would be needed to change the volume to 2.2 liters?
149K
4L of neon are at 323 K. The next day, the temperature decreases to 290 K, what is the new volume? Express your answer as a number with two sig figs only.
3.6
What is the pressure of a 1.0 L container with 0.60 g of He at 293 K?
3.61 atm
Using the circumference of the balloon, calculate the volume of the gas produced. Circumference = radius/ 2 pi (3.14) Volume of a sphere= (4/3)pi r^3Answer as a number only with four sig figs in cubic centimeters.
351.2
What is the pressure of a 3.00 L gas vessel that has 18.0 grams of helium at 25 degrees Celsius?
36.7 atm
If the number of moles of a gas initially in a 2.10 L vessel is doubled, what is the final volume of the gas in liters?
4.20
What is the molar concentration of phosphate(PO4)^-3 in a 1.50 M Na3PO solution?
4.50 M
What is he pH of a solution with a concentration of H_{3}O^{+} of 1.7 x 10^ -5M ?
4.77
Which of the following substances can act as either a Lewis acid or a Lewis base? Choose all correct answers as there may be more than one.
Ag^{+}, Al^3+, H{2}O
What do you think would be the biggest source of error in this lab?
All answer choices could be a source of error A.Misshapen balloons b. Loss of water when deflating baloon c.Reaction not complete d.All answer choices could be a source of error
1 atm is equal to:
All of the Above A.760 mm Hg b.760 torr c. 101,325 Pa d.14.7 psi e all of the above
How is the Arrhenius definition of acids and bases limited?
All of the above A.does not consider electrons and protons B.involves hydrogen and hydroxide only C.Based upon aqueous solutions only
What is true about colligative properties?
All of the above. A.The freezing point is lowered by addition of salt. b.The mass of the solvent is a factor in molality. c.The identity of the solute is not a factor of molarity or molality.
What is occurring when one makes ice cubes?
An endothermic processes
What definition of acids and bases is based upon hydronium and hydroxide only?
Arrhenius
Could these values be obtained without this simulation? If so, how? If not, why not?
Yes, because the formula for Molarity could be used in each instance.
Which solution below would have the highest concentration of hydroxide ions?
pH=12.49
What is the volume of 28.0 g of nitrogen gas at STP?
22.4
What are some examples of acids?
lemons
What is the freezing point of a water solution using .85 m concentration? Freezing point constant is 1.86
-1.6
A 0.15 M solution of BaCl{2} contains the following ions:
0.15 M Ba^{ 2+} ions and 0.30 M Cl^{-} ions
At what point is Copper II sulfate a saturated solution at a volume of with 0.200 liters?
0.150 mol
What is the molarity of a solution that contains 15.5 g NaCl in a 1.50 L solution?
0.177M
What is the molality of a solution with 0.455 moles of solute in a 1.97 kg solvent? Express your answer as a number with three sig figs only. Do not enter the space-holder zero. Ex: do not enter 0.201 but instead .201
0.231
What is the molarity of a solution that contains 1.58 mol of glucose (C6H12)6) in a 5.0 L solution? Express your answer as a number with two sig figs only. Do not enter a 0 before the initial decimal point. For example, do not enter 0.17 but instead enter .17.
0.32
From the correct answer on lab question 7.01, convert the cubic centimeters to liters. Use three sig figs only. Numeric Answer:
0.351
What is the final volume of a .5 L gas container that increased in temperature from 299 K to 333 K when pressure increased from 1.00 atm to 1.54 atm?
0.362 L
The boiling point constant for water is 0.512 degrees Celsius kg/mol. Calculate the change in boiling point for a 0.907 m solution. Answer as a number only with three sig figs. Do not enter a 0 before the initial decimal point. For example, enter .512 instead of 0.512.
0.464
A balloon has 0.500 L of air in it and is submerged in water at a depth with a pressure of 3.25 atm. What is the volume of the balloon at that depth?
0.5
What is the final volume of a cylinder that was initially 0.5 L at 25 degrees Celsius and was then heated to 50 degrees Celsius?
0.542 L
How many grams of Barium chloride are produced if 0.0253 L of 0.113 M BaCl_{2} react? Use the following equation below: BaCl{2}(aq) + Na{2}SO{4}(aq)-> BaSO{4} (s) + 2NaCl(aq)
0.588 g BaCl{2}
Initial volume in a cylinder is 750 ml, if pressure changes from 840 mm Hg to 360 mm Hg, what is the final volume of this gas?
1.750 L
What is the concentration of hydronium ions in a neutral solution?
1.0 x 10 ^{-7} M
What is the equilibrium concentration of hydroxide?
1.00
Using 1 mole of Gold II chloride, what volume is needed to achieve a 1 M solution?
1.00 L
Convert the atmospheric pressure found in this lab from mm Hg to atm. Round to three sig figs.
1.00 atm
What is the equilibrium concentration of hydronium?
1.00 x 10 ^{-2}
What is the equilibrium concentration of hydroxide?
1.00 x 10 ^{-2}
What is final P (in atm) with 3.05 L at 724 mmHg and 298 K which is compressed to 2.51 L at 273 K?
1.06
If a mixture of gases contained nitrogen at a pressure of 0.762 atm and oxygen at a pressure of 0.431 atm, what is the total pressure of this system?
1.19 atm
What is the molality of a solution with 12.5 g of ethylene glycol (C2H6O2) dissolved in 135 g of water?
1.49 m
The freezing point constant for water is 1.86 degrees Celsius kg/mol. Calculate the change in freezing point for a 0.907 m solution. Answer as a number only with three sig figs.
1.69
What is the final volume (L) of a 1.78 L system at 315 K and 1.10 atm if STP conditions are established? Express your answer as a number with three sig figs.
1.7
How many Liters of 0.112 M Na{2}CO{3}will react completely with 27.2 Liters of 0.135 M HNO3 according to the equation below? 2HNO_{3}(aq) + Na_{2}CO_{3}(aq)-> H_{2}O(l) + CO_{2}(g) + 2 NaNO_{3} (aq)
16.4 L
A 14.8L balloon is at 255K. What is its volume if its temperature is 304K? Answer by using a number with three sig figs only.
17.6
What is the equivalent pressure of 1520 torr in units of atm?
2.00
What is the molarity of KCl prepared by dissolving 0.525 moles in KCl in a 0.250 L solution?
2.1
Find P1 using Boyle's Law if the following values are used: V1= 1.90 L, P2= 4.19 atm, and V2= 1.09 L. State your answer as a number with two sig figs in atm.
2.4
What is the pH of a solution that has H_{3}O^{+} of 0.0039M?
2.41
Which set of conditions reflect STP?
273 K, 1 atm
The gas in the balloon is carbon dioxide. Using the value for n in the answer from lab question 7.03 and the mass of the gas generated (from lab information up top), what is your value for the molar mass of CO2. (n= mass/molar mass) Answer with a number with three sig figs only.
40.3
What is the mass of carbon dioxide? Answer as a number only with two sig figs
44.0
2NH3(G) ---> N2G + 3H2(G) If 15.0 L of nitrogen formed at STP, how many liters of hydrogen will be produced?
45.0 L
What is the molality of a solution made by dissolving 14.7 g C{6}H{12}O{6} in 1.5 ml of water? Density of water is 1.00 g/mL.
54.4
Calculate the pH of a solution with H{3}O^{+} = 7.2 x 10^{ -9} M.
8.14
If the initial pressure of a system was 1.00 atm and the volume was halved and the temperature was tripled, what is the final pressure?
6.00 atm
What is the temperature of 3.48 moles of gas in a 20.0 L container at 660 mm Hg?
60.8 K
Hydrogen gas occupies 2 liters of volume at a temperature of 32 degrees Celsius. What is its temperature when it has a volume of 4 liters? Answer as a number with two sig figs only.
64.0
A sample of gas has an initial volume of 4.95 L at a pressure of 700 mm Hg. If the volume of the gas is increased to 5.38 L, what is the pressure?
644 mm Hg
With requires 35.7 L HNO3} of 0.108 M Na{2}CO{3} to react with 0.117M of the HNO_{3}. What is the volume of 2HNO{3}(aq) + Na{2}CO{3}(aq) -> H{2}O (l) + CO{2} (g) + 2NaNO{3}(aq)
65.9 L
What is the equivalent pressure of 0.905 atm in units of mm Hg?
688
What is the pH of pure water?
7
What is the pH of normal and healthy human blood? Enter a number with one digit only. Numeric Answer:
7.0
A solution has a pH of 6. What is the pOH of the solution?
8
What is the percent error for the value of the mass of carbon dioxide? value from lab calculation-periodic table value/ periodic table value x 100 Answer as a number with two sig figs-this represents the percent. Make sure to round correctly.
8.4
How many moles of gas were added to a cylinder that started with 2.3 moles of gas and a volume of 1.4 L given that the final volume was 7.2 L? express your answer as a number with two sig figs only.
9.5
Which combination below represents a buffer solution?
A HC{2}H{3}O{2} and NaC{2}H{3}O{2}
What is the pH of water according to this simulation?
Between 7-8
What happens to the blue hydroxide ions when strength of base is increased?
Hydroxide ions increase in number.
How is the Bronsted-Lowry definition of acids and bases different than the Lewis definition of acids and bases?
Bronsted-Lowry deals with protons and Lewis deals with electrons.
How could the Lewis theory be depicted in this simulation?
By showing electron dot structures.
What is true about a solution with a pH of 5.00?
H{3}O^{+} is 1.0 x 10^{ -5}M
Fill in the Blanks ___________ law refers to partial pressures of a gas.
Daltons
Which gas law involves most or all of the others?
Ideal gas law
What does Charles Law provide an explanation for?
Explains why hot air balloons float.
Which substance below represents the hydronium ion?
H3O+
Which substance would be labeled as the conjugate base in the following reaction? H{3}CCOOH (aq) + H{2}O (l) -> H{3}CCOO- + H{3}O^{+}
H_{3}CCOO^{-}
Explain the reason for your response to Lab question 9.03.
Hydronium ions increase in acids.
Explain the reason for your response to lab question 9.05.
Hydroxide ions increase in a base.
What happens to the red hydronium ions when strength is increased?
Ions increase in number.
What differences did the amount of salt used make?
It affected how long it took the ice cream to freeze. and It affected the temperature of the water.
A solution has a pH of 13 and another solution has a pH of 10. How does the concentration of H{3}O^{+} in the solution with a pH of 13 compare to the H{3}O^{+}concentration in the solution with a pH of 10?
It is 1000 times stronger.
What unit of temperature is used in the Ideal Gas Law?
Kelvins
Fill in the Blanks Lake _____________ is being studied due to the disastrous results from a supersaturated solution of carbon dioxide.
Nyos
What is the conjugate base of water?
OH-
What is the proper form of the combined gas law?
P1V1/T1= P2V2/T2
What problem could happen if deep sea divers used pure oxygen in their tanks?
oxygen toxicity
Why did Procedure 3 take longer than expected?
Solute percentage was larger than solvent percentage
What happened when salt was added to the ice?
The freezing point was lowered (freezing point depression).
Which of the following statements is true about gases?
The pressure of a gas is due to collisions of those molecules.
A specific volume of gas was maintained in a container. If the pressure of the gas in the container doubled, what would happen to the temperature?
The temperature doubled.
Since carbon dioxide is soluble in water, would this make the molar mass value in this lab too high or too low?
The value would be the same.
How can buffers be used?
To neutralize stomach acid
For an ideal gas, which of the following pairs of variables are directly proportional to each other (if all other factors remain constant)?
V, T
What happens to the volume of a balloon when placed in ice water? What law does this apply to?
Volume decreases as temperature decreases according to Charles law.
What happens to the volume of a gas when you triple the number of moles of gas (everything else constant)?
Volume triples.
What happens if you add solvent?
Water increases.
If sea level pressure is 1 atm, is the total pressure of the gases mentioned in Homework Question 7.08 at sea level, above or below sea level based upon that answer?
above
Fill in the Blanks Lemons are an example of an _____________
acid
What happens as heat is added to a solid?
all of the above A. Continued heating increases rate of melting. b. When melting point is reached, the energy allows the intermolecular forces to be overcome.
What is evaporation?
all of the above a.increased with increased temperature b.endothermic c.opposite is condensation d.a cooling process
Fill in the Blanks Bases are not common in foods due to their ________________ taste.
bitter
What are some properties of bases?
bitter taste, turns red litmus paper blue
What are some examples of bases?
cleaning products
Fill in the Blanks Gas molecules ________________ with one another like billiard balls according to the Kinetic Molecular Theory.
collide
Fill in the Blanks __________- properties depend on the number of dissolved solute particles and not on the specific type of solute.
colligative
What appears to be forming in the Copper II sulfate solution once it becomes saturated?
crystals
Fill in the Blanks A __________ solution contains a small amount of solute relative to the amount of solvent.
dilute
Which intermolecular force is common to polar molecules but not to nonpolar molecules?
dipole-dipole forces
How would you classify this experiment?
endothermic
What is the primary reason for water's unique properties?
hydrogen bonding
Which intermolecular force is the strongest?
hydrogen bonding
Fill in the Blanks Ideal gases follows the _________ molecular theory.
kinetic
What is the Arrhenius definition of an acid?
produces H+
How is sodium hydroxide used?
production of soap
How does a buffer work?
resists changes to pH
If a solution is prepared by adding enough solute such that after heating and cooling, there is still a visible amount of solid at the bottom of the beaker, this solution would be considered:
saturated
Which of the following is not a property of acids?
slippery
What are some properties of acids?
sour taste, turns blue litmus paper red
What is the measure of the resistance to the flow of a liquid?
viscosity
Fill in the Blanks The usual products of an acid/base reaction are ________ and______________ .
water, Salt
