Chapter Two: Freezing Point Depression Measurements Purpose: The purpose of this lab is to measure freezing points and freezing point depression for several solutions. The freezing point depression constant (Kf) for p-xylene was calculated from freezing point measurements and used to estimate the molar masses of three unknown solutes in a p-xylene solution. The end goal of this lab experiment is to correctly identify these three unknown solutes. The molar mass of a solute is able to be determined through freezing point depression measurements because the increase in solutes disrupts crystal formation, requiring a lower temperature to form a lattice. This colligative property is important in many industries, but is clear to see when using ordinary salt to remove ice from steps or a driveway.
The manufacturing of these little soldiers for athletes relies on the principles of thermochemistry. The mixture of ammonium nitrate and water relies on endothermic properties or in this case when heat is absorbed to create the cold sensation in an ice pack. A device used to measure the quantity of heat transferred to or from an object is called a calorimeter. In most science labs it is more commonly referred to as a Styrofoam cup or a coffee cup calorimeter. In our lab we use a more sophisticated one which included a lid on the cup with an inserted thermometer and a stirrer.
Distillation is used to purify a compound by separating it from a non-volatile or less-volatile material. When different compounds in a mixture have different boiling points, they separate into individual components when the mixture is carefully distilled. The boiling point is the temperature at which the vapor pressure of the liquid phase of a compound equals the external pressure acting on the surface of the liquid. The external pressure is usually the atmospheric pressure. Different compounds boil at different temperatures because each has a different, characteristic vapor pressure: compounds with higher vapor pressures will boil at lower temperatures.
Distillation is a liquid purification process using heating and cooling. Real World Application Vapor pressure is used in distillation to purify a compound by separating it from non-volatile material. The lowering of the vapor pressure causes molecular movement along the surface of a liquid and through processes of evaporation and vapor cooling; the compound is separated and distilled into its purer forms. Distillation there are many uses for colligative properties in the real world, and decreasing of vapor pressure is among the many that are implemented into modern techniques and technology today. "Colligative Properties of Solutions."
When cold water cools, ice crystals use the tiny bubbles as starting points for formation. Hot water was heated, making the dissolved gasses disappear. Since there are no bubbles in the hot water, there aren’t as many starting points for the ice crystals. Dissolved gasses also lower the freezing point. Since heated gas is likely to freeze first.
In order to understand the lab one must also understand endothermic and exothermic reactions. When a solid dissolves in water heat is either absorbed or released, which results in either an endothermic or exothermic reaction. An endothermic reaction is defined as the process in which energy, as heat, flows from the surrounding into the system. While an exothermic reaction is defined as the process in which energy, as heat, flows out of the system into the surroundings. When an endothermic reaction occurs, heat it taken in making the pack cool down, and in an exothermic reaction occurs heat is released making the pack warm up.
hoSpecific heat capacity in liquids Specific heat capacity in liquids How do liquid filled radiators work and what are the useful properties of these liquids? Liquid-filled electric radiators are sealed units that have an internal heating element that releases heat through the outer case; however the elements are put in a liquid such as: oil, water or heat transfer agent. Depending on the design of the radiator, the heat generated can be through radiation or a combination of radiation and convection (1). (10) (10) The liquid used is anti-freeze which is made up of ethylene and propylene glycol (13). Ethylene glycol is mixed with water so it is 50% of each liquid in the solution and has the highest boiling point than any other radiator fluid (5); its boiling point is 197.3°C and has a melting point of -12.9°C (12).
Explain. It is valid to conclude that a base were added, the rate of the reaction would slow down because the pressure of oxygen barely increased, meaning the enzymes were not working at a faster rate. 6. Predict what would happen if vinegar (also known as acetic acid) were added to a water solution of hydrogen peroxide and
Certain enzymes are specific to pH levels at which they work best, and removing them from this environment may denature the enzyme. Much like pH levels, enzymes have an optimal temperature level, and again in a different temperature extreme, enzymes will denature. However, other than only environmental factors, enzymes can also have their reactions affected by both activators, which increase reaction rates, and inhibitors, which slow or stop reactions. In an experiment involving the unexpected lowering of pH in an enzyme's environment, we can see how the enzyme will become denatured because of this. Materials: 2A) Hydrogen peroxide, catalase solution, beakers/test tubes, pipette, ice for catalase, water for boiling, liver/potato tissue 2B) Hydrogen peroxide, water, sulfuric acid, potassium permaganate, beakers/test tubes, pipette 2C) Hydrogen peroxide, beakers/test tubes, sulfuric acid, potassium permaganate, pipette 2D)
When the gas comes out of the ground, it comes out wet. The first stage of the refining process involves on-site heating of the gas to 212 degrees to evaporate any non-methane hydrocarbons and fluids that are mixed into the gas. (Arthur, 2008) The condensate that is generated from this process is then vented into the atmosphere. The condensate often contains the same chemical additives that are added to the well during the fracking process, as well as volatile organic compounds that are naturally occurring in the ground where the gas is stored (Witter,