Please any help would be much appreciated!!! A pair of students performed an exp
ID: 619137 • Letter: P
Question
Please any help would be much appreciated!!!
A pair of students performed an experiemnt to determine the heat of formation of zinc oxide. The reactions are entirely analogous to the reactions of magnesium oxide. They reacted 1.504 g of zinc with 100.20 g of 0.50 M hydrocholoric acid. (Zinc is the limiting reagent.) The initial temperature was 23.11 C and the final temperature was 31.36 C. If the heat capacity of zince chloride solution formed in this reaction is 4.06 J ^-1 C^-1 and the caloimeter constant is 7J C^-1, calculate enthalpy change for the quantity of zinc reacted. Be sure to follow the significant figures convention in the answer you report.
Explanation / Answer
Zn (s) + 2HCl (aq) ---> ZnCl2(aq) + H2(g) moles of hcl=100.2/36.5=2.7452 moles, vol=2.7452*0.5=1.3726 lit moles of zn=0.023 moles concentration=0.023/1.3726=0.0167565 M zncl2 formed=3.135 gm enthalpy change=4.06/3.125*(31.36-23.11)+7*(31.36-23.11)=68.47 J/g