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.
In this experiment, the amount of energy (heat) involved in a chemical change will be determined. When alcohol burns it produces carbon dioxide and water as products. Energy is also released in the reaction. The alcohols that will be used are, methanol CH3OH, ethanol CH3CH2OH, propanol CH3(CH)2OH, butanol C4H9OH, octanol C8H18O, and paraffin wax C25H52. The heat obtained when a known mass of alcohol or paraffin wax burns will be used to warm a measured volume of water.
In the experiment a secondary alcohol (cyclohexanol) is heated with acid (phosphoric acid). A carbocation is generated by the loss of water from cyclohexanol because of the protonated alcohol. Loss of hydrogen ion from the carbocation will give the desired alkene (cyclohexene). Fractional distillation is used to separate liquids that have different boiling points that are relatively close together. By using this method of distillation a mixture is heated to a temperature at which several fractions of the compound is evaporated the distillate is then condensed and collected.
To do this, the metal will be heated, and then put into water to determine the heat transferred. The heat that is transferred from the metal to the water is measured using the equation: Eq. 2 q(water) = -q(metal) The heat of water is positive because it was initially cold, and because the hot metal was being added to it, it gained heat. The heat of the unknown metal is negative because of the loss of heat it is experiencing when submerged in cold water. The specific heat constant for water, 4.184 J/g C, is used for this equation.
Calculations involving the Mole, Avogadro’s Number, Molar Mass, Mole-Mole and Mass-Mole calculations in chemical equations. Combustion analysis and calculation of empirical and molecular formulas from composition analysis. Electrolytes and non-electrolytes. Precipitation reactions and solubility rules. Writing balanced molecular equations and net ionic equations.
G C S E S P E C I F I C AT I O N GCSE Specification Chemistry For exams January 2012 onwards For certification June 2013 onwards GCSE Specification Chemistry 4402 This specification is published on the AQA website (aqa.org.uk). We will let centres know in writing about any changes to the specification. We will also publish changes on our website. The version on the website is the definitive version; this may differ from printed versions. Further copies of this specification booklet are available from: AQA Logistics Centre (Manchester), Unit 2, Wheel Forge Way, Ashburton Park, Trafford Park, Manchester, M17 1EH Or, you can download a copy from the AQA website: aqa.org.uk Copyright © 2011 AQA and its licensors.
Sodium sulfate + Lead(II) nitrate Lead(II) sulfate + Sodium nitrate Type of reaction = ________________________________ 20. Some of the reactions on this worksheet produced water as one of the reaction products. What similarities and differences do you see between these reactions? 21. A reaction in which a substance reacts with oxygen and produces water as one of the products is often referred to a s Combustion reaction.
Water samples from the Clark Fork have been taken and will be tested using both absorption and emissions spectroscopy in order to check the levels of group IA and IIA metal ions. When electrons in an element are excited energy is released that can be measured as light. Each element releases different levels of energy that are observed as different wavelengths of light. With the proper equations (E=hv and E=hc/⋋), emission spectroscopy can be used to find the wavelength and frequency of light emitted by the excited electrons. This will help determine the types of ions present in the water sample.
When the fuels combust, oxygen and fuels react, and heat released. The water then absorbed the heat from the combustion. In this experiment the calorimeter of energy is used to measure the temperature of the heat that is released from the cashew. The equation to find the energy produce during
Title Hydrochloric acid and sodium thiosulphate: how reaction rate varies with sodium thiosulphate Concentration Introduction When sodium thiosulphate reacts with hydrochloric acid, sulphur is produced. The sulphur that is produced forms in very small particles and causes the solution to cloud over and turn a yellow colour. This basic word equation sums up the reaction: HCL + sodium thiosulphate sodium chloride + sulphur dioxide + sulphur + water The aim of this experiment is to observe and record the rate of reaction of hydrochloric acid and sodium thiosulphate; a conical flask above a marked 'x' will be filled with the required amounts of hydrochloric acid and sodium thiosulphate and then the amount of time it takes for the reaction to occur and for the marked 'x' to disappear will be measured. The scientific principle in effect here is the collision theory. The collision theory is the theory that molecules have to collide in a certain way with a certain amount of energy in order to react and form a new product; when molecules collide that can react, they need a certain amount of energy (also known as activation energy) in order to break existing bonds and then form new bonds as the new product.