Assignment on Chemical Change

Added on -2021-02-21

| 7 pages| 1661 words| 343 views

Trusted by 2+ million users,
1000+ happy students everyday

Showing pages 1 to 3 of 7 pages

Chemical Change (Chemistry A-Level)
Table of ContentsSection 1...........................................................................................................................................3Calculate the molarity of a solution............................................................................................3Section 2...........................................................................................................................................3(A) Identify exothermic and endothermic reactions from their standard enthalpy changed data.....................................................................................................................................................3(B) Enthalpy change in 2Al(s) + Fe2O3(s) → Al2O3(s) + 2Fe(s):............................................4Section 3...........................................................................................................................................4(A) Determine the order of reaction given the rate equation......................................................4(B) Calculate the reaction order with respect to the concentration of ethyl chloride(CH3CH2Cl)...............................................................................................................................4Section 4...........................................................................................................................................5(A) For the following reactions, determine the equilibrium constant equation.........................5(B) Explain the effect of changing pressure, concentration of a reactant or product ortemperature on the composition of a reaction mixture in equilibrium........................................6References........................................................................................................................................7
Section 1Calculate the molarity of a solutionMolarity can be described as number of moles of the substance per litre of the liquid. Itis used to express the concentration of the solution (Sholl and Lively, 2016). Molarity = Moles of solutes/Volume in litres of solution1. Molarity = 8.75 moles of NaCl/6.22 Litres = 1.407 M NaCl2. No. of moles of NaOH = 428g*1 Mol/39.997g = 10.701 MolMolarity = 10.701/6.4L = 1.672 M NaOH3. Molarity = Moles of solutes/Volume in litres of solutionVolume in litres of solution = Moles of solutes/MolarityVolume = 4.85Mol /0.75 M = 6.467 Litres4. Molarity of Sodium hydroxide = No. of moles of NaOH/Volume of solution in litresNo. of moles of NaOH => Density of NaOH (ρ) = Moles of NaOH/Volume of solution => Moles of NaOH = ρ * Volume => 2.13 * 37.0 = 78.81 MolesMolarity of NaOH = 78.81/37.001 = 2.123 MSection 2(A) Identify exothermic and endothermic reactions from their standard enthalpy changed dataThe chemical reactions which release energy in the form of heat, light or sound then they areknown as an exothermic reactions. They are demoted by a negative heat flow i.e. heat is lost tothe surroundings and reduction enthalpy occurs (ΔH < 0). However, some of chemical reactionsare responsible for absorbing energy in order to proceed then they are known as endothermicreactions (Wen and et. al., 2016). These chemical reactions are characterised by positive heatflow and increase in enthalpy (+ΔH). 1. N2 + 2O2 → 2NO2 ΔH = +68kJ mol–1 This reaction between nitrogen and oxygen is known as an endothermic chemicalreaction because it shows a positive flow of energy. 2. C3H8 + 5O2 → 3CO2 + 4H2O ΔH = -2220kJ mol–1 The reaction among propane and oxygen is termed as an exothermic chemical reaction asit release energy and shows negative glow of enthalpy. 3. 2H2 + O2 → 2H2O ΔH = -486.3kJ mol–1

Found this document preview useful?

You are reading a preview
Upload your documents to download
or
Become a Desklib member to get accesss

Students who viewed this