10 Magnesium carbonate decomposes when heated in a Bunsen burner flame.Values for the standard enthalpies of formation, , of the species involved are shown.MgCO 3 = –1095.8 kJ mol –1MgO = –601.7 kJ mol –1CO 2 = –393.5 kJ mol –1What is the standard enthalpy change for the decomposition of magnesium carbonate?A +100.6 kJ mol –1B +887.6 kJ mol –1C +1095.8 kJ mol –1D +2091 kJ mol –

PURPOSE: The purpose of this lab is to determine the molar enthalpy of combustion (ΔHCOMB) of Magnesium. Mg + ½O2 → MgO This reaction is too dangerous to carry out directly to measure the enthalpy Dangers of Burning Magnesium. Instead of carrying out this target reaction directly we will be carrying out two of the known reactions (1 & 2) and the 3rd known reaction value is also too dangerous to carry out so its value is given. TARGET: Mg(s) + ½O2(g) → MgO(s) ΔH = KNOWN EQUATIONS: 1) Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) ΔH = kJ 2) MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) ΔH = kJ 3) H2(g) + ½O2(g) → H2O(l) ΔH = -285.8 kJ Two experiments will be carried out using calorimetry to determine the ΔH for Reaction 1 & Reaction 2. EXPERIMENT # 1 Experiment #1 (Known Reaction 1 above) Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) will be carried out using calorimetry. A certain mass of Mg will be added to a certain volume of HCl. The AQUEOUS solution of HCl is very DILUTE so we will consider it WATER for our calculations.Once the Mg is placed in the HCl the t1 will be taken and once the reaction is over (the temperature stops changing) the t2 will be taken. Watch this video link for Experiment 1 and enter the data into the observation table. (4 marks) Mass of Mg g Mass of HCl (mL=g) g t1 oC t2 oC *** Remember HCl is going to be considered H2O CALCULATIONS FOR EXPERIMENT #1 Use the data above and calculate the molar enthalpy (ΔHx) of the reaction in terms of Mg. HINT you need to do the 2 steps for this calculation ΔH = mcΔt & ΔH = nΔHx and this answer will be your ΔH value for your KNOWN equation #1. The video mentions figuring out the Limiting Reagent but it is Mg that you are calculating in terms of. (6 marks) EXPERIMENT # 2 Experiment #2 (Known Reaction 2 above) MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l)will be carried out using calorimetry. A certain mass of MgO will be added to a certain volume of HCl. The AQUEOUS solution of HCl is very DILUTE so we will consider it WATER for our calculations.Once the MgO is placed in the HCl the t1 will be taken and once the reaction is over (the temperature stops changing) the t2 will be taken. Watch this video link for Experiment 2 and enter the data into the observation table. (4 marks) Mass of MgO g Mass of HCl (mL=g) g t1 oC t2 oC *** Remember HCl is going to be considered H2O CALCULATIONS FOR EXPERIMENT

The diagram shows some of the reactions of magnesium.(a) Complete the table to give the identity of substances F, G and H.substance Identitysolution Fgas Gdilute acid H(b) Write a chemical equation for the reaction between magnesium and steam.4. A student was asked by his teacher to perform a flame test on a solid. He used this method.● dip the tip of a clean platinum wire into hydrochloric acid and then into the solid● adjust the air hole of the Bunsen burner to obtain a non - roaring, non – luminousBunsen flame● place the tip of the platinum wire into the edge of the flame● observe the colour in the flame(a) (i) why is it important that the platinum wire is clean?

When magnesium is burnt, heat and light are produced. The burning of magnesium is a:A.reversible changeB.physical changeC.chemical and exothermic changeD.chemical and endothermic change

alculate the enthalpy of the following reaction: (3 marks)2Mg + O2 → 2MgOGiven:Mg + 2HCl → MgCl2 + H2 ΔH = -21.0 kJMgO + 2HCl → MgCl2 + H2O ΔH = -33.5 kJH2 + ½ O2 → H2O ΔH = -76.0 kJ

Burning the magnesium will produce a single compound. Predict whether the compound produced will have more or less mass than the magnesium you start off with.Give a reason for your prediction.