Question

How would the following errors affect the calculated values of the molar mass (high, low, or...

How would the following errors affect the calculated values of the molar mass (high, low, or no effect), if you were not aware that they had occured? Explain your answers.

a. A small amount of unknown adheres to the inside of test tube and did not get dissolved in the cyclohexane.

b. Some solvent is lost by volitilization.

c. The thermometer used in this experiment was miscalibrated to read 0.5 C lower than the actual temperature over its entire scale.

Science   Chemistry   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

A technique to determining the molar mass is determining the fusion point change. To calculate the fusion point change, we use:

Where, Kf is the crioscopic constant of the solvent, "m" is the molality. Then:

a) If you DISSOLVES a solute into a solvent, the fusion point decreases. NO EFFECT

b) If some solvent is lost by volatilization, then the molality increases and increases too. Then, when you calculate "m", you will get a higher value than the real. HIGH

c) will be lower than the real, so "m" will be lower too. LOW.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Would the calculated molecular weight be too high, too low, or unaffected if the following occured?...
Would the calculated molecular weight be too high, too low, or unaffected if the following occured? Explain a) Some benzophenone adheres to the test tube walls above the solution. b) Some unknown adheres to the test tube walls above the solution c) The freezing point depression is calculated from super-cooled BZP
1) We have assumed that the unknown does not dissociate into more than one particle when...
1) We have assumed that the unknown does not dissociate into more than one particle when dissolved. If this was an incorrect assumption and the solid did dissociate slightly. Then how would the calculated molar mass of solute from our experiment differ from the actual molar mass? The calculated would be (too high, too low or unaffected) compared to the actual? Explain briefly. 2)If you measured the experimental freezing point of 30g cyclohexane with 0.012mols of Toluene (MWT= 92.15) and...
1) We have assumed that the unknown does not dissociate into more than one particle when...
1) We have assumed that the unknown does not dissociate into more than one particle when dissolved. If this was an incorrect assumption and the solid did dissociate slightly. Then how would the calculated molar mass of solute from our experiment differ from the actual molar mass? The calculated would be (too high, too low or unaffected) compared to the actual? Explain briefly. 2)If you measured the experimental freezing point of 30g cyclohexane with 0.012mols of Toluene (MWT= 92.15) and...
1) We have assumed that the unknown does not dissociate into more than one particle when...
1) We have assumed that the unknown does not dissociate into more than one particle when dissolved. If this was an incorrect assumption and the solid did dissociate slightly. Then how would the calculated molar mass of solute from our experiment differ from the actual molar mass? The calculated would be (too high, too low or unaffected) compared to the actual? Explain briefly. 2)If you measured the experimental freezing point of 30g cyclohexane with 0.012mols of Toluene (MWT= 92.15) and...
1) We have assumed that the unknown does not dissociate into more than one particle when...
1) We have assumed that the unknown does not dissociate into more than one particle when dissolved. If this was an incorrect assumption and the solid did dissociate slightly. Then how would the calculated molar mass of solute from our experiment differ from the actual molar mass? The calculated would be (too high, too low or unaffected) compared to the actual? Explain briefly. 2)If you measured the experimental freezing point of 30g cyclohexane with 0.012mols of Toluene (MWT= 92.15) and...
Determine the molar mass of the solute. If 2.35 g of the unknown compound were dissolved...
Determine the molar mass of the solute. If 2.35 g of the unknown compound were dissolved in 30.46 g of PDB ( Kfp for PDB = 7.10 C/m) m=molality = moles solute/kg solvent Molar mass= grams of substance/mole of substance 1. Molar mass of solute is___________ On this molar mass calculation in a freezing point depression experiment determine the effect on molar mass, will it be higher, lower, or not change. 2. The thermometer you were using read temperatures consistently...
How would the following errors affect the final mass of copper in this experiment? (a) Small...
How would the following errors affect the final mass of copper in this experiment? (a) Small amounts of water remained in the beaker after in the beaker after washing with acetone and drying your sample for a week. (b)While a small amount of solid is lost with the decanted liquid. Copper metal recovered would be less than expected as some amount of Cu(OH)2 is still unconverted.
Explain how each of the following errors Part B would affect the calculation of the molar...
Explain how each of the following errors Part B would affect the calculation of the molar mass of the unknown. (which would have been Cyclohexane ,C6H12, molar mass=84.2, boiling point=80.7) (4): 0.3703g (6): Temp of vapor in flask 102C 375.15K (7): Barometric Pressure- 30.35in * 2.54cm/1in * 10mm/1cm= 770.89 --> 1.01 atm (8): Volume of Erlenmeyer flask- 147 mL 0.147 L M= (step4)(0.0821L atm/mole)(6) / (step 7)(step 8) = 76.8 g/mol <---that should have been 84.2 if we would have...
READ THE CASE STUDY AND ANSWER THE FOLLOWING QUESTIONS 2nd CASE: An Unexplained Death A 65-year-old...
READ THE CASE STUDY AND ANSWER THE FOLLOWING QUESTIONS 2nd CASE: An Unexplained Death A 65-year-old man of Scandinavian descent was rushed to the Emergency Room of your local hospital after a family member discovered him unconscious in his home. The woman who dialed “911” told the dispatcher that the man, her brother, was the local librarian of the past 10 years and had no spouse or children. She reported that they had spoken the day before, and he had...
Sign In INNOVATION Deep Change: How Operational Innovation Can Transform Your Company by Michael Hammer From...
Sign In INNOVATION Deep Change: How Operational Innovation Can Transform Your Company by Michael Hammer From the April 2004 Issue Save Share 8.95 In 1991, Progressive Insurance, an automobile insurer based in Mayfield Village, Ohio, had approximately $1.3 billion in sales. By 2002, that figure had grown to $9.5 billion. What fashionable strategies did Progressive employ to achieve sevenfold growth in just over a decade? Was it positioned in a high-growth industry? Hardly. Auto insurance is a mature, 100-year-old industry...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT