A.P. Chem Unit 3 Solutions Review

Explain how the concentration of a solution can be calculated using absorbance and the molar absorptivity.

• concentration = absorbance + (molar absorptivity * path length)

• concentration = absorbance * (molar absorptivity * path length)

• concentration = absorbance - (molar absorptivity / path length)

• concentration = absorbance / (molar absorptivity * path length)

Explain the concept of path length and its impact on the application of Beer's law.

• Shorter path length increases the concentration of the sample

• Path length has no impact on Beer's law

• Longer path length affects the absorbance of the sample, leading to a higher concentration being measured.

• Longer path length decreases the absorbance of the sample

What is the relationship between absorbance and concentration according to Beer's law?

• Absorbance is proportional to the square of concentration

• Absorbance has no relationship with concentration

• Absorbance is directly proportional to concentration

• Absorbance is inversely proportional to concentration

Chromatography separates solutions on the basis of _____ while distillation separates solutions on the basis of ______.

• IMFs; solubility

• solubility; conductivity

• IMFs; boiling point

• boiling point; solubility

You have a 0.5 M MgSO₄ stock solution available.  Calculate the volume of the stock solution needed to make 2.0 L of 0.20 M MgSO₄.

• 0.8 L
• 5 L 
• 0.1 L
• 0.5 L

A dissolved solute that does not form ions is

• a nonelectroyte

• a weak electrolyte

• a strong electrolyte

• insoluble

Which does not affect the rate at which a solid solute dissolves?

• the vapor pressure of the solvent

• the temperature of the solvent

• the surface area of the solid

• the speed at which the solution is stirred

How many grams of solute are dissolved in 125.0 mL of 5.00 M NaCl (MM = 58.45)?

• 0.625 g NaCl
• 625 g NaCl
• 36.5 g NaCl
• 0.04 mol NaCl

A student extracts the colour from some green smarties and uses paper chromatography to separate components colours. She finds blue has a R_f =0.38 and yellow R_f =0.75 this suggests 

• the yellow is more strongly adsorbed onto the stationary phase and is less soluble in the mobile phase.

• the yellow is more strongly adsorbed onto the stationary phase and is more soluble in the mobile phase.
• the blue is more strongly adsorbed onto the stationary phase and is less soluble in the mobile phase.

• the blue is less adsorbed onto the stationary phase and is more soluble in the mobile phase.

The R_f value  for the blue component is 

• 0.3
• 0.7
• 10
• 3