Chem 30 Lab

Hess Law Lab DESIGN outlook 1 puzzle What is the counterspyar enthalpy of formation of magnesium oxide? Variables Manipulated None Responding None Controlled closing off of calorimeter, concentrations of fondnesss involved. Aspect 2Background Information Assumptions Specific heat capableness of water, we bust that the acid has the same qualities as water including heat capacity, and we assume the enthalpy of formation for magnesium oxide from the data booklet for theoretical value.Hesss Law Hess law states that the energy change for any chemical or physical process is independent of the pathway or number of steps required to complete the process provided that the final and sign reaction conditions be the same. In other words, an energy change is path independent, only the initial and final states being of importance. Waste disposal and safety Corrosive substance which causes severe but delayed burns. DO NOT INGEST. Avoid Inhalation. prompt as instructed by the lab technician or the teacher. Aspect 3frame-up Diagram Figure from Inquiry into chemistry textbook pg 352Materials 1. 00 mol/L HCl(aq) MgO(s) powder milligram ribbon Simple calorimeter 100 mL gradational cylinder Scoopula Electric balance Thermometer Sand paper Procedure 1. Mg(s)+ O2(g) MgO(s) 2. MgO(s)+2HCl(aq) MgCl2(aq)+ piss(l) 3. Mg(s)+2HCl(aq) MgCl2(aq)+H2(g) 4. H2(g)+ O2(g) H2O(l) + 285. 8kJ area 1 Determining ? H of Reaction (2) 1. Set up the transparent calorimeter refer to figure 9. 16 above. Using a graduated cylinder, check 100 mL of 1. 00mol/L HCl(aq) to the calorimeter. 2. usher the initial temperature of the HCl(aq) to the nearest ordinal of a degree. 3.Find the mass of no more than 0. 80 grams of MgO(s) powder. accede exact mass. 4. Add the MgO(s) powder to the calorimeter containing the HCl(aq) swirl the antecedent gently, recording the highest temperature reached. 5. slash as directed by teacher. Part 2 Determining ? H of reaction (3) 1. Using a graduated cylinder, add 100mL of 1. 00mol/L HCl to the calorimeter. 2. Record initial temp. of hydrochloric acid to the nearest tenth of a degree. 3. If you are victimisation magnesium ribbon, sand ribbon to desired mass. Determine mass no more than 0. 50 grams of magnesium.Record the exact mass. 4. Add the Mg(s) to the calorimeter containing the HCl(aq). Swirl the solution gently, recording the highest temperature, tf , reached. 5. Dispose as directed. DATA COLLECTION & PROCESSING (DCP) Aspect 1Recording Raw Data Temperature of hydrochloric acid and mass of Magnesium oxide sess of Magnesium oxide (g)Initial Temperature (C)Final Temperature (C) 0. 7523. 5029. 50 Temperature of hydrochloric acid and mass of magnesium Mass of magnesium (g)Initial Temperature (C)Final Temperature (C) 0. 4824. 0045. 00 Aspect 2Processing Raw Data heat content change of Magnesium oxide MgO(s)+2HCl(aq) MgCl2(aq)+H2O(l) Q=mc? t ? t= 29. 50C-23. 50C? t = 6 C Q= (0. 00075kg) x x 6C Q= 0. 018855kJ/mol MgO Enthalpy change of magnes ium reaction Mg(s) +2HCl(aq) MgCl2(aq)+H2(g) Q=mc? t ? t=45. 00C-24. 00C? t= 21C Q= (0. 00048kg) x x 21C Q= 0. 0422352kJ/mol Mg ?HH2O = -285. 8 kJ/mol (given in data booklet) ?Hrxn = 0. 018855kJ/mol MgO + 0. 0422352kJ/mol Mg + 285. 8kJ/mol H2O ?Hrxn = 285. 86109 kJ/mol MgO ? H system = -? H surroundings %error= x 100% %error= %error= -52. 48%