The Organic Chem Lab Survival Manual: A Student's Guide to Techniques
10th Edition
ISBN: 9781118875780
Author: James W. Zubrick
Publisher: WILEY
expand_more
expand_more
format_list_bulleted
Question
Chapter 12, Problem 4E
Interpretation Introduction
Interpretation:
Never remelt any sample and they don’t just cool and solidify in exactly the reverse manner that they heated and melted is to be explained.
Concept Introduction:
The melting point of a substance is the temperature at which it changes state from solid to liquid. This change occurs in atmospheric pressure and during melting point the two phases (solid and liquid) exist in equilibrium.
Usually take melting points in thin, closed-end tubes called capillary tubes, they are also called melting-point tubes or even melting-point capillaries.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Which method would you use to determine water content in packaging material, pharmaceuticals and cosmetics? Mention few advantages of this method.
Suppose a student heated the hydrate sample for approximately five seconds instead of one minute. What would be the
result of not heating the sample long enough?
The solid sample will completely decompose into water and anhydrate.
Water may still remain in the solid sample.
There might be insufficient heat to form the hydrate.
The volume of the hydrate sample will increase.
2. The goal behind suction filtration is to remove soluble impurities that are on the
surface of the crystals. Therefore, why can't you simply use suction filtration
instead of recrystallization to purify an impure solid?
Chapter 12 Solutions
The Organic Chem Lab Survival Manual: A Student's Guide to Techniques
Knowledge Booster
Similar questions
- Sublimation is preferred over recrystallization when you work with an amount of solid material to be purified that weighs: A) at least 1 kg B) about 100 mg C) about 1 mol D) about 1000 ml A ODarrow_forwardIn the above image, you have a solid at less than 0 oC. As you add heat (Q), the temperature of the solid increases until it hits a point when it would start melting. In the case of water, this is at 0 oC. Notice that at this point the temperature stops rising and we have a mixture of solid/liquid. We are still adding heat but the temperature is not changing. Once all of our solid becomes liquid, the temperature starts to rise again until it hits another plateau, at 100 oC. This is the point where the water boils and starts becoming a gas. Again, we add heat but the liquid/gas mixtures temperature does not change. Once all the liquid has become gas, the temperature will start to rise again. Is it possible to have 0 oC water and 0 oC ice? Yes or No?arrow_forwardCorrelate solidification with crystallization(Explanation needed).arrow_forward
- Recall the last time you bought a cup of coffee or hot chocolate on a particularly cold day. The cup likely felt warm when you held it in your hand. The cup your beverage came in is not too different from the ones we used in this experiment. Based on this, do you think a coffee cup is a perfect insulator? If not, how might this affect your results? Group of answer choices No; the specific heat calculated is lower than it should be due to the heat lost Yes; the specific heat calculated is lower than it should be due to the heat lost No; results will not be affected since the calorimeter contains all heat indefinitely Yes; results will not be affected since the calorimeter contains all heat indefinitelyarrow_forwardCloth can be waterproofed by coating it with a silicone layer. This is done by exposing the cloth to (CH3)2SiCl2 vapor. The silicon compound reacts with OH groups on the doth to form a waterproofing film (density = 1.0 g/cm3) of [(CH3)2SiO]n, where n is a large integer number. n (CH3)2SiCl2 + 2n OH 2n Cl + n H2O + [(CH3)2SiO]n The coating is added layer by layer, with each layer of [(CH3)2SiO]n being 0.60 nm thick. Suppose you want to waterproof a piece of doth that is 3.00 square meters, and you want 250 layers of waterproofing compound on the cloth. What mass of (CH3)2SiCl2 do you need?arrow_forwardWhat is formed when gas is enclosed in a chamber then liquified under very high pressure? * What latent heat value signifies the lost of heat during a phase change? What is the unique temperature and pressure at which the three phases of a substance are in equilibrium with each other? * Which liquid crystal is of pharmaceutical significance? *arrow_forward
- In heating liquids in a test tube, why should the tube not be pointed to anyone while it is being heated?arrow_forward3. Is solid > liquid → gas an endothermic or exothermic process? Describe how this energy change affects the energy of the molecules and their intermolecular forces.arrow_forwardWhy do impure compounds normally have a lower melting point than the pure substance?arrow_forward
- B. SOLID TO GAS Place a few crystals of iodine in a dry test tube. Heat the tube and note the changes. Cool the tube. Observations: What happens when the tube is heated? What is this substance? Does any iodine melt? What is formed on cooling the tube? What is this process called? Define it. Name another substance that could undergo such a process.arrow_forwardPure benzophenone melts at 48.1 C. Your sample of benzophenone began to freeze at 47 C. When you repeated this measurement, the sample again began to freeze at 47 C. Give at least two reasonable explanations for this observation. You tried to read the thermometer when your solution containing the unknown began to freeze but were not certain if the reading was 43.5 C or 44 C so you decided to repeat this by melting the solidifying mass. The new reading you observed was clearly 41 C. What happened? Clearly explain your reasoning.arrow_forward1. Explain the PVT behavior of pure substances with appropriate examples.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781337399074
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781133949640
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning