Freezing Point Depression - Chemistry LibreTexts
What is the molality of the solution? Ex: A solvent's vapor pressure, boiling point, freezing point, and osmotic pressure are all colligative properties. Explain the relationship between a liquid's vapor pressure and its boiling point. the freezing point of an aqueous solution obtained by diluting the above xNH3. 3H2O Q which of the following relation between XA (mole fraction of A in. Freezing-point depression is the decrease of the freezing point of a solvent on addition of a the molality is increased temporarily as a reaction to cold temperatures. This simple relation doesn't include the nature of the solute, so this is only.
- How does molality affect the freezing point?
- Subhashish Sir
- How do you calculating freezing point from molality?
In the coldest parts of the Arctic, much of the ground is bare, non-vascular plants such as lichens and mosses predominate, along with a few scattered grasses, herbivores on the tundra include the Arctic hare, lemming, muskox, and caribou.
They are preyed on by the owl, Arctic fox, Grizzly bear 6. Fish — A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits.
They form a group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous, tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well.
However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods, because in this manner the term fish is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces is considered a typological, but not a phylogenetic classification, the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period.
Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts, fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms.
Many fish of the Paleozoic developed external armor that protected them from predators, the first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods.
Fish are abundant in most bodies of water and they can be found in nearly all aquatic environments, from high mountain streams to the abyssal and even hadal depths of the deepest oceans. With 33, described species, fish exhibit greater species diversity than any group of vertebrates.DEPRESSION IN FREEZING POINT ( COLLIGATIVE PROPERTIES ) - SOLUTION-(CHAPTER-2) CLASS 12
Fish are an important resource for humans worldwide, especially as food, commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by fishers, kept as pets, raised by fishkeepers. Fish have had a role in culture through the ages, serving as deities, religious symbols, fish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event.
Early fish from the record are represented by a group of small, jawless. Jawless fish lineages are mostly extinct, an extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils, the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways.
The first ancestors of fish may have kept the form into adulthood. Fish are a group, that is, any clade containing all fish also contains the tetrapods 7. Rainbow smelt — The rainbow smelt is a species of fish of the family Osmeridae.
Its distribution is circumpolar, and it has introduced to the Great Lakes. Walleye, trout, and other larger fish prey on these smelt, the rainbow smelt prefer juvenile ciscoes, zooplankton such as calanoid copepods, and other small organisms, but are aggressive and will eat almost any fish they find. They are anadromous spring spawners and prefer clean streams with light flow, the rainbow smelt face several barriers.
They are weak swimmers and cannot overcome most fish ladders and this prevents them from making it past the dams to the headwater streams where they spawn. The rise in erosion and dams help to decimate the population in the s. There are currently plans to try to reduce damming and to control erosion.
With current efforts to reduce the impact on this and many other affected species the population is back on the rise. The body of the rainbowsmelt is slender and cylindrical and it has a silvery, pale green back and is iridescent purple, blue, and pink on the sides, with a light underside.
When full grown, the smelt is between 7 and 9 inches long and weighs about 3 ounces. Individuals over 12 inches long are known, the rainbow smelt is widespread across North American watersheds. Rainbow smelt invaded the Great Lakes watershed through an introduction of eggs to Crystal Lake in This lake drains into Lake Michigan, from which fish escaped into Lake Michigan and spread throughout the Great Lakes.
The ability of smelt to disperse is determined by the connectivity of lakes, the ability of smelt to move through connecting streams. Rainbow smelt are weak swimmers so they make it over fish ladders.
This has helped to prevent a wider spread of their range.
Rainbow smelt occur in rivers, coastal areas and ponds, in their anadromous territories, they spend the summers along the coast, normally in waters no more than 20 feet deep and no more than 1 mile from shore 8. Spring peeper — The spring peeper is a small chorus frog widespread throughout the eastern United States and Canada. They are so called because of their chirping call that marks the beginning of spring, there are two subspecies, The northern, P.
The southern is distinguished by a dark marking on its belly. They have a length between less than 1 in to 1. The species has large toe pads for climbing, although it is more at home amid the debris of the forest floor. The color variations of the P. Located by its throat, this frog has a sac which expands and deflates like a balloon to create a short. Only males have the ability to make this loud high-pitched noise, Spring peepers live primarily in forests and regenerating woodlands near ephemeral or semipermanent wetlands.
This amphibious species requires marshes, ponds, or swamp regions to support the environment the eggs.
Freezing Point Depression
In the northern reaches of their range, spring peepers must frequently endure occasional periods of subfreezing temperatures during the breeding season, the species can tolerate the freezing of some of its body fluids, and undergoes hibernation under logs or behind loose bark on trees. The southern spring peepers habitat includes the Gulf Coast from southeastern Texas to southeastern Georgia and northern Florida and its northern conspecific occurs in the entire United States east of the Mississippi and spreads to eastern and central Canada.
Spring peepers are nocturnal insectivores, emerging at night to feed primarily on invertebrates, such as beetles, ants, flies. They do not climb high into trees, but hunt in low vegetation, Spring peepers living in deep, damp forests are active hunters both day and night, whereas those found in woodland edges restrict most hunting and other activity to night. Tadpoles feed on algae and other organisms in the water and their predators include great diving beetle larvae, snakes, skunks, and larger frogs.
As their common name implies, the spring peeper has a call similar to that of a young chicken, only much louder. They are among the first frogs in the regions to call in the spring, as a chorus, they resemble the sounds of sleigh bells 9. De-ice — De-icing is defined as removal of snow, ice or frost from a surface. On the ground, when there are freezing conditions and precipitation, frozen contaminants cause critical control surfaces to be rough and uneven, disrupting smooth air flow and greatly degrading the ability of the wing to generate lift, and increasing drag.
This situation can cause a crash, if large pieces of ice separate when the aircraft is in motion, they can be ingested in engines or hit propellers and cause catastrophic failure. In flight, droplets of supercooled water often exist in stratiform and they form into ice when they are struck by the wings of passing airplanes and abruptly crystallize.
This disrupts airflow over the wing, reducing lift, so aircraft that are expected to fly in such conditions are equipped with a de-icing system. De-icing techniques are employed to ensure that engine inlets and various sensors on the outside of the aircraft are clear of ice or snow. Deicing fluids consisting of propylene glycol and additives are used by airlines for deicing aircraft.
Ethylene glycol fluids are still in use for aircraft de-icing in some parts of the world because it has an operational use temperature than PG. However, PG is more common because it is less toxic than ethylene glycol, when applied, most of the deicing fluid does not adhere to the aircraft surfaces, and falls to the ground. Airports typically use containment systems to capture the used liquid, so that it cannot seep into the ground, even though PG is classified as non-toxic, it pollutes waterways since it consumes large amounts of oxygen as it decomposes, causing aquatic life to suffocate.
First, it must not contribute in the vapor pressure of the solution and second, it must remain suspended in the solution even during phase changes. Because the solvent is no longer pure with the addition of solutes, we can say that the chemical potential of the solvent is lower. Chemical potential is the molar Gibb's energy that one mole of solvent is able to contribute to a mixture.
SparkNotes: SAT Chemistry: Solutions
The higher the chemical potential of a solvent is, the more it is able to drive the reaction forward. Consequently, solvents with higher chemical potentials will also have higher vapor pressures.
Boiling point is reached when the chemical potential of the pure solvent, a liquid, reaches that of the chemical potential of pure vapor. Because of the decrease of the chemical potential of mixed solvents and solutes, we observe this intersection at higher temperatures.
Supersaturated solutions are often formed by heating a solution and dissolving more solute, then cooling the solution down slowly. These solutions are unstable and crystallize readily. Concentration Terms Solutions are often referred to as being concentrated or dilute.
These two terms are very general. While concentrated indicates that there is a lot of solute dissolved in the solvent perhaps the solution is near to being saturated and dilute indicates that a small amount of solute is dissolved in the solvent, we often need to be exact with quantities in chemistry. Molarity M The molarity of a solution is a measure of the number of moles of solute per liter of solution.
This is the most common concentration unit used in chemistry. For instance, you might see an expression that looks like this: The brackets around the number indicate that the concentration is expressed in terms of molarity. Example Calculate the molarity of a solution prepared by dissolving Explanation Then convert mL to liters: Dilution Dilution is the process of taking a more concentrated solution and adding water to make it less concentrated. The more concentrated solution before the dilution is performed is known as the stock solution.
You can relate the concentration of the stock solution to the concentration of the diluted solution using the equation below: Try the following example using this equation. Example What volume of 6. Explanation Just plug the numbers into the formula! Be careful to read closely.
Mass Percent Weight Percent The mass percent of a solution is another way of expressing its concentration. Now try a problem involving the equation: Example A solution is prepared by mixing 5.
Calculate the mass percent of ethanol in this solution.
Solutions for AP Chemistry | Brainscape
Explanation Plugging the values we were given into the mass percent equation, we get: Molality m The molality of a solution is a measure of the number of moles of solute per kilogram of solvent. Whereas the molarity of a solution is dependent on the volume of the solution, the molality is dependent on the mass of the solvent in the solution.
Example A solution is prepared by mixing Calculate the molality of this solution. Explanation Convert grams of solute to moles: