B) permanent dipoles of molecules containing covalent bonds between atoms of very different electronegativities. C) the hydrophobic effect. D) ion pairing between oppositely charged functional groups. Answer: A Page Ref: Section 5 28) The aggregation of nonpolar molecules or groups in water is thermodynamically due to the A) increased entropy of the nonpolar molecules when they associate. B) decreased enthalpy of the system.
PRELIMINARY CHEMISTRY ASSESSMENT TASK 1. Identify the sources of pollution which accompany the combustion of organic compounds and explain how these can be avoided. Combustion refers to the burning of a substance in oxygen. It is a process in which a self-sustained chemical reaction occurs at temperatures above those of the surroundings. Combustion of organic compounds can result in detrimental impacts on the environment such as the generation of acids and production of carbon monoxide, particulates and soot.
But HOH is a weaker base, and better leaving group. Adding a strong acid to the mixture allows protonation of the –OH group to give water as a leaving group. Once this protonation occurs, the mechanism that is followed depends on the nature of the R group (Williamson, Kenneth L.). In the presence of a strong acid, an alcohol can be dehydrated to form an alkene. The acid used in this experiment is 85% phosphoric acid and the alcohol is cyclohexanol.
Glycerol has some useful properties. It is a solvent and a solute (it can dissolve and be dissolved). When mixed with water, it lowers the freezing point and can then be used as a lubricant. It has a boiling point of 290°C and a melting point of 17.8°C (14). Glycerol is colourless and thick (11) so in comparison to
Course # Student name / Names of members of group Date: Exp # : Estimating the effects of acid rain Introduction: Precipitation that measures a pH value below 5.6 is generally considered as acid rain. Burning fossil fuels is the main reason for the elevated levels of gaseous oxides in a polluted atmosphere that in-turn forms acid rain. Gaseous oxides such as that of carbon, sulfur, nitrogen and phosphorus could dissolve in water to form an acidic solution. A generalized reaction sequence on the formation of acid rain is as follows; One of the determinants of clean water in the natural environment is its alkalinity. Alkalinity can be defined as the capacity to neutralize acids.
The salts will be dissolved in distilled water by small quantities until the reaction reaches When ionic compounds dissolve in water, they either absorb energy from or release energy to the surroundings. If a chemical reaction absorbs heat from the surroundings, it is an endothermic reaction. If a solution releases heat to its surroundings, it is an exothermic reaction. The enthalpy of dissolution is the enthalpy change associated with the dissolution of a substance in a solvent at a constant pressure. The change in enthalpy relies on the concentration of the salt solution, because different concentrations will produce different enthalpies.
There will have some error. 2) A volatile liquid was allowed to evaporate in a 43.298 g flask that has a total volume of 252 ml. the temperature of the water bath was 100˚C at the atmospheric pressure of 776 torr. The mass of the flask and condensed vapor was 44.173 g. calculate the molar mass of the liquid. T = 273 + 100 = 373 V = 252 mL = 1 L / 1000 mL = 0.252 L P = 776 Torr R= 0.0821 mass of 44.173 - 43.298 g = 0.875g moles of gas = PV / RT = 776 x .252 / 62.363 x (273+100) =0.00841 moles molar mass = 0.875g / 0.00841 moles = 104.1 g/
high melting point, hard, brittle, slightly soluble in water, conductor of electricity when melted or in solution Molecular solid - crystalline solid that has molecules arranged in a particular configuration. low melting point, generally insoluble in water, nonconductor of electricity. Metallic solid - crystalline solid that has atoms of metals arranged in a definite pattern. low to high melting point, malleable, ductile, conductor of electricity, insoluble in most solvents. Lesson 13.6 Changes of physical state: * necessary to draw a temperature-energy graph to see the change in temperature with a constant application of heat Heat of fusion - the amount of heat required to melt 1.00 g of substance.
CHE 111 Laboratory 3 Hydrates Introduction Hydrates Water molecules combine with the molecules of certain substances, forming loose chemical combinations called hydrates. An example of a hydrate is MgSO4•7H2O. This formula means 7 water molecules are loosely attached to a magnesium sulfate molecule. Other examples of hydrates are Na2SO4•10H2O and Ba(OH)2•8H2O. When the hydrate is heated, it easily loses water molecules attached and becomes an anhydrous salt.
The heat from the steam decreases the viscosity of the heavy crude oil or bitumen which enables it to move down into the lower well chamber. The steam and gases rise because of their low density compared to the heavy crude oil below. The gases released, such as carbon dioxide, methane, and hydrogen sulfide, tend to rise into the steam chamber, filling the void space left by the oil. Oil and water flow countercurrent, gravity driven drainage into the lower well. The condensed water and crude oil is recovered at the surface by pumps such as progressive cavity pumps that work well with high viscosity fluids and suspended