MISC 01 - Sample Problems Flashcards
In a solution, 40 mL of solute can dissolve 0.08 g of a drug. What is the solubility of this drug in grams per 100 mL of water?
0.2 g
If 10 mL of a solution contains 0.005 g of a dissolved compound, what is the concentration in mg/mL?
0.5 mg/mL
A 15mL sample solution contains 0.06g of solute. How much solute is there in 75mL of the solution?
0.3 g
A drug is soluble at 0.1 g per 25 mL of solvent. How much solvent is needed to dissolve 2 g of the drug?
500 mL
A drug has a solubility of 0.5g per 100mL at 25°C. If a saturated solution is prepared with 250mL of water, and then 50mL of water evaporates, how much of the drug will precipitate?
0.25 g
A solute’s solubility is 0.6g per 50mL at 30°C and increased by 50% at 50°C. If 150mL of a solution is prepared at 30°C and then heated at 50°C, how much more solute can be added to reach saturation?
0.9 g
A reference sample with a viscosity of 0.9 Poise, density of 1.0g/cm3, and a flow time of 40 seconds is used in an Ostwald Viscometer. Another sample liquid has a density of 0.8 g/cm3 and a flow time of 50 seconds. Find the viscosity of the sample in Poise.
0.9 Poise
An Ostwald viscometer measures a reference liquid with a viscosity of 1.2 Poise, a density of 1.0g/cm3 and a flow time of 60 seconds. A sample liquid with a density of 1.1 g/cm3 has a flow time of 45 seconds. Calculate the viscosity of the test liquid in (dynes x sec)/cm2.
0.99 (dynes x sec)/cm2
An unknown liquid is tested using an Ostwald viscometer with a reference liquid having an absolute viscosity of 1.5 Poise, a density of 1.2 g/cm3 and a flow time of 70 seconds. The unknown liquid has a flow time of 80 seconds and a density of 1.0 g/cm3. If the viscosity of the unknown liquid is to be converted to (dynes x sec)/cm2, what is the viscosity?
1.43 (dynes x sec)/cm2
An Ostwald viscometer is used to measure two liquids: a reference liquid with an absolute viscosity of 1.0 Poise and a flow time of 50s, and a test liquid that has a flow time of 60 s. Both liquids have the same density. Calculate the relative viscosity of the test liquid compared to the reference liquid.
1.2
Using the Ostwald viscometer, the time required for acetone to flow between two marks of the capillary viscometer was 45 seconds and for water the time was 100 seconds at 25°C. The density of acetone is 0.786 g/cm3 and that of water is 0.997 g/cm3 at 25°C. The viscosity of water is 0.8904cp at this temperature. Calculate the viscosity of acetone.
0.31588 cp
Calculate the surface tension of an unknown sample at 20°C using water standard. 17gtts of water weigh 66.25g and 20gtts of unknown weighs 68g. Surface tension of water at 20°C = 72.8 dynes/cm.
63.51 dynes/cm
Calculate the surface tension of a 2% (w/v) solution of a wetting agent that has density of 1.008 g/mL and that rises 6.6 cm in a capillary tube having an inside radius of 0.2 mm.
65 g/sec2
The surface tension of benzene at 20°C is 28.85 dynes/cm. In a capillary apparatus the liquid rose to a height of 1.832cm. The density of benzene is 0.8765g/mL. Calculate the diameter of the capillary tube in mm.
0.7328 mm
