Upgrade to remove ads
Only $35.99/year

Practical Practice Exam

Terms in this set (24)

T/F: you should use a beaker to measure 12.0mL
false
T/F: adding NaCl will lower the boiling point of water
false
T/F: dissolving brass into nitric acid produces a red solution
false
-it produces a red/brown fume
T/F: measuring color change over time is useful in determining the reaction rate
true
T/F: the pH of a titration of weak acid with strong base will be acidic
true
T/F: the pH of NaCl will be basic
false
NaCl is a neutral salt
T/F: adding NaOH will separate Ni2+ and Ca2+
true
NaOH forms a precipitate with aluminum, calcium, and magnesium
T/F: a positive galvanic cell voltage means the system is releasing energy
true
T/F: accuracy is how close data is to its known value
true
A student made a sample of Cu(NO3)2 by dissolving a metal alloy in concentrated nitric acid. The student measured the absorption of the colored solution using a UV-Vis spectrophotomer to detect the amount of Cu2+ cations in the solution. What is the approximate concentration of Cu2+ ions in the sample if the absorption maximum at the desired wavelength was much lower than a standard solution of Cu2+ ions?
a. The concentration is higher than the standard solution
b. The concentration is lower than the standard solution
c. The concentration is about the same as the standard solution
d. We need more information
b. the concentration is lower than the standard solution

because absorption is directly proportional to concentration, and the Cu2+ concentration was lower than the standard solution
When dissolving metals in nitric acid, what is the major safety concern about the products?
a. the products will be destroyed by the nitric acid
b. the production of toxic brown NO2 gas
c. the products are explosive
d. the products give off UV light
b. the production of toxic brown NO2 gas
What would you expect the pH of a potassium acetate solution to be?
a. weakly acidic
b. strongly acidic
c. strongly basic
d. neutral
a. weakly acidic
it is the salt of weak acetic acid
What technique is the fastest and most effective method for separating a very fine solid from a mixture?
a. vacuum filtration
b. titration
c. precipitation
d. centrifugation
d. centrifugation
separates particles according to size
A student assembled a galvanic cell using nickel and zinc. What would be the appropriate electrolyte solutions that the student should use for each half cell?
a. water for both of the half cells
b. nickel (II) hydroxide for the Ni half-cell and zinc hydroxide for the Zn half-cell
c. nickel (II) nitrate for the Ni half-cell and zinc nitrate for the Zn half-cell
d. sodium chloride for both half-cells
c. nickel (II) nitrate for the Ni half-cell and zinc nitrate for the Zn half-cell
the electrolyte solution is the solution that the solid is similar to- Nickel put in the Ni nitrate solution
nitrate is a good medium
When assembling a galvanic cell using silver and copper, what would not be a good choice of a salt bridge solution?
a. NaNO3 (aq)
b. KNO3 (aq)
c. LiNO3 (aq)
d. NaCl (aq)
d. NaCl
salt bridge must be a medium that doesn't react with the solutions
If you had a solution the ions Cr3+, Co2+, Pb2+ , K + , Li+ , Na+ , Ag+, and Ca2+, which ions would you be able to precipitate if you added sodium hydroxide?
a. Cr3+, Co2+, Pb2+ , K + , Li+ , Na+ , Ag+ , Ca2+
b. Cr3+, Co2+, Pb2+, Ag+
c. Na+ , Ag+ , Ca2+
d. Pb2+ , K + , Li+ , Na+
b. Cr3+, Co2+, Pb2+, Ag+
any metallic ions (on left side of line)
When using a UV-Vis spectrophotometer, what should you blank the system with if you are testing a solution of cobalt (II) chloride in 100% ethanol?
a. 50/50 mix of water and 100% ethanol
b. water
c. 100 % ethanol
d. cobalt (II) chloride in water
c. 100 % ethanol
must be a solution similar to testing solution
A titration of an unknown weak, monoprotic acid was done by using 12.45 mL of 0.341 M of NaOH. The unknown acid solution was made by dissolving 0.541 g of the acid in solid form in 50.41 mL of distilled water. What are the concentration and the molecular weight of the unknown acid?
a. 0.0843 M 127 g/mol
b. 0.1686 M 63.5 g/mol
c. 4.25 x 10-2 M 127.29 g/mol
d. 1.24 M 92.5 g/mol
a. 0.0843 M 127 g/mol
lost
What compound would you add to a solution to detect the presence of Fe3+ ions?
a. ammonia
b. HCl
c. H2O2
d. AgNO3
a. ammonia
What happens to the absorbance of the solution if the solution appears cloudy?
a. nothing
b. the absorbance would be lower than expected
c. the absorbance would be higher than expected
d. a negative absorbance would be seen
c. the absorbance would be higher than expected
absorbance is proportional to concentration
If the freezing point of solvent is -80.3 °C, what would happen to the freezing point of the solvent if a large amount of a non-volatile solute is added?
a. the freezing point would decrease to a lower temperature
b. the freezing point would increase to a higher temperature
c. the freezing point would not change
d. the freezing point would double
a. the freezing point would decrease to a lower temperature
What would happen to the amount of each species in an acetic acid/sodium acetate buffer system if a small amount of a strong acid is added to the buffer solution?
a. some of the acetic acid will be consumed while some of the acetate ion will be increased
b. both ion concentrations will stay the same
c. both ion concentrations will be consumed and both will increase
d. some of the acetate ion will be consumed while some of the acetic acid will be increased
d. some of the acetate ion will be consumed while some of the acetic acid will be increased
When performing a titration of an unknown diprotic acid with a strong base, how many equivalence points should you see when you plot the pH vs the volume of strong base added?
a. one
b. three
c. two
d. four
c. two
diprotic
What would the pH of the resulting solution be when adding equal moles of ammonium hydroxide and hydrobromic acid and what species is dictating the pH?
a. weakly acidic due to NH4Br
b. weakly basic due to NH4Br
c. strongly acidic due to NH4Br
d. neutral due to H2O
a. weakly acidic due to NH4Br
Other sets by this creator