CHEM 101L QuEstions witH AnswErs 100%
CorrECt
Based on your observations in Experiment 5, an exothermic reaction may be identified via observation in
the lab when it: ✔✔ -Causes a loud popping noise.
-Grows warm
In a conductivity titration, 10.15 mL of 4.95 x 10-3 M Ba(OH)2 is titrated by a 4.15 x 10-3 M H2SO4
solution. The end point of the titration would be expected at a volume of: ✔✔ 12.11 mL
A conductivity plot for the titration of barium hydroxide with sulfuric acid is shown below. Assuming
sulfuric acid is the titrant, which ion species would you expect to be significant in solution when 11.62
mL of titrant had been added?
y = -40.313x + 415.69
y = 35.924x + 358.27 ✔✔ -SO42-
-H+
The molecular equation for the reaction in Experiment 4 is: AgNO3 + LiCl →AgCl + LiNO3 How is
conductivity reflected in the net ionic equation? ✔✔ Silver nitrate is a soluble ionic substance that is
highly conductive in solution, and lithium chloride is a strong electrolyte that also conducts in solution. In
contrast, silver chloride is an ionic solid, and, as a solid, it is nonconductive. Lithium nitrate is a soluble
ionic substance that exhibits lower conductivity. Therefore, the ionic equation will have two spectator
ions, lithium and nitrate, that will be written as ions in solution.
During a conductivity titration, 15.00 mL of 0.00495 M Ba(OH)2 is placed in a beaker with 35 mL of H2O.
The predicted end point of the titration with 0.00495 M H2SO4 was at a volume of 15.00 mL, but the
results of titration consistently gave an end point from 18.20-18.31 mL. A well-reasoned explanation for
this result would be: ✔✔ The concentration of the barium hydroxide was higher than what was reported
on the label.
In the reaction KOH(s) + HBr (aq) → KBr(aq) + H2O(l), the spectator ion(s) would be: ✔✔ Br-
, To carry out a calorimetry experiment quantitatively, which of the following would be necessary: ✔✔ -
The thermometer must be calibrated to give accurate temperature readings in °C.
-All solutions must be equilibrated to room temperature before beginning the experiment.
-Calculations must be made in moles rather than in grams.
-The calorimeter must be calibrated to account for heat loss from the system.
In calorimetry, the enthalpy change of the reaction, qrxn, is defined to be: ✔✔ The heat gained or lost
by the reaction in units of joules or -(qsoln + qcal)
In a calorimetry experiment, 50.0 mL each of two dilute aqueous solutions are combined and produce an
extrapolated ΔT = 22.4C̊. If the density of each solution is assumed to be equal to that of water (at 20C̊, d
= 0.9982 g/mL), and the specific heat of the solution is also equal to that of water (4.186 J/gC̊), the value
of qrxn would be: ✔✔ -9.36 kJ
The graph shows the calibration of a spectroscope against a series of emission lines of known
wavelength. Based on this calibration, which is the wavelength of a line that appears at 5.34 mm on the
spectroscope scale?
y = 0.0108x - 0.4235 ✔✔ 534 nm
Which item used during Experiment 8 required calibration? ✔✔ The spectroscope
When viewed through a spectroscope, calcium ions produce three distinct lines in the visible region of
the spectrum, at spectroscope positions of 7.30, 7.85, and 8.45. Assuming the linear fit for the
calibration of the spectroscope has a positive slope, the line corresponding to the highest energy would
have a spectroscope position of: ✔✔ 7.30
Given the Rydberg equation: ΔE = RH (1/(nf2)- 1/(ni2))
In the Balmer series for hydrogen, what is the initial energy level (ni) for a photon with a wavelength of
434.1 nm? REMEMBER: h = 6.626 x 10-34 J⋅s; c = 2.998 x 108 m/s; RH = 2.18 x 10-18 J ✔✔ 5
CorrECt
Based on your observations in Experiment 5, an exothermic reaction may be identified via observation in
the lab when it: ✔✔ -Causes a loud popping noise.
-Grows warm
In a conductivity titration, 10.15 mL of 4.95 x 10-3 M Ba(OH)2 is titrated by a 4.15 x 10-3 M H2SO4
solution. The end point of the titration would be expected at a volume of: ✔✔ 12.11 mL
A conductivity plot for the titration of barium hydroxide with sulfuric acid is shown below. Assuming
sulfuric acid is the titrant, which ion species would you expect to be significant in solution when 11.62
mL of titrant had been added?
y = -40.313x + 415.69
y = 35.924x + 358.27 ✔✔ -SO42-
-H+
The molecular equation for the reaction in Experiment 4 is: AgNO3 + LiCl →AgCl + LiNO3 How is
conductivity reflected in the net ionic equation? ✔✔ Silver nitrate is a soluble ionic substance that is
highly conductive in solution, and lithium chloride is a strong electrolyte that also conducts in solution. In
contrast, silver chloride is an ionic solid, and, as a solid, it is nonconductive. Lithium nitrate is a soluble
ionic substance that exhibits lower conductivity. Therefore, the ionic equation will have two spectator
ions, lithium and nitrate, that will be written as ions in solution.
During a conductivity titration, 15.00 mL of 0.00495 M Ba(OH)2 is placed in a beaker with 35 mL of H2O.
The predicted end point of the titration with 0.00495 M H2SO4 was at a volume of 15.00 mL, but the
results of titration consistently gave an end point from 18.20-18.31 mL. A well-reasoned explanation for
this result would be: ✔✔ The concentration of the barium hydroxide was higher than what was reported
on the label.
In the reaction KOH(s) + HBr (aq) → KBr(aq) + H2O(l), the spectator ion(s) would be: ✔✔ Br-
, To carry out a calorimetry experiment quantitatively, which of the following would be necessary: ✔✔ -
The thermometer must be calibrated to give accurate temperature readings in °C.
-All solutions must be equilibrated to room temperature before beginning the experiment.
-Calculations must be made in moles rather than in grams.
-The calorimeter must be calibrated to account for heat loss from the system.
In calorimetry, the enthalpy change of the reaction, qrxn, is defined to be: ✔✔ The heat gained or lost
by the reaction in units of joules or -(qsoln + qcal)
In a calorimetry experiment, 50.0 mL each of two dilute aqueous solutions are combined and produce an
extrapolated ΔT = 22.4C̊. If the density of each solution is assumed to be equal to that of water (at 20C̊, d
= 0.9982 g/mL), and the specific heat of the solution is also equal to that of water (4.186 J/gC̊), the value
of qrxn would be: ✔✔ -9.36 kJ
The graph shows the calibration of a spectroscope against a series of emission lines of known
wavelength. Based on this calibration, which is the wavelength of a line that appears at 5.34 mm on the
spectroscope scale?
y = 0.0108x - 0.4235 ✔✔ 534 nm
Which item used during Experiment 8 required calibration? ✔✔ The spectroscope
When viewed through a spectroscope, calcium ions produce three distinct lines in the visible region of
the spectrum, at spectroscope positions of 7.30, 7.85, and 8.45. Assuming the linear fit for the
calibration of the spectroscope has a positive slope, the line corresponding to the highest energy would
have a spectroscope position of: ✔✔ 7.30
Given the Rydberg equation: ΔE = RH (1/(nf2)- 1/(ni2))
In the Balmer series for hydrogen, what is the initial energy level (ni) for a photon with a wavelength of
434.1 nm? REMEMBER: h = 6.626 x 10-34 J⋅s; c = 2.998 x 108 m/s; RH = 2.18 x 10-18 J ✔✔ 5
