Fall CHEM 110 Recitation 2 Recitation)2)Group)Problems) 1. In#the#lab#a#substance#is#studied#and#the#following#observations#are#made.###At#room#temperature#(20°C)#the#substance#has#the#following#properties:#1. It#is#a#solid#that#is#shiny#and#silver#in#color.##2. It#has#a#density#of#1.738#g/cc##3. It#is#malleable#(it#can#be#pounded#into#a#flat#sheet.)##4. It#is#ductile#(it#can#be#pulled#into#a#thin#wire).##5. It#is#a#good#electrical#conductor.##The#substance#is#subjected#to#some#further#experiments#and#these#additional#observations#are#made.##6. It#melts#at#649°C##7. It#boils#at#1105°C.##8. It#burns#in#air,#glowing#with#an#intense#white#light.##9. It#reacts#with#bromine#to#give#a#brittle#white#solid###Which#of#these#characteristics#are#physical#properties,#and#which#are#chemical#properties?#PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP#2A.#How#many#protons,#neutrons#and#electrons#are#present#in#235U4+?What#does#the#4+#indicate?#What#does#the#number#235#indicate?###2B.#Which#of#these#species#has#45#neutrons?#A.#80Kr#B.#80Br## #C.#78Se#D.#79Kr#E.#80Rb#PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP#3.#Natural#uranium#mined#from#the#Earth#contains#the#isotopes#uraniumP238,#uraniumP235#and#uraniumP234.##The# majority# (99.2745%)# of# all# the# atoms# in# natural# uranium# are# uraniumP238.##Most# #of# the# remaining##atoms# #(0.72%)# #are# #uraniumP235,# #and# #a# #slight# #trace# #(0.0055%)# #are# uraniumP234.# # Determine# the#average#atomic#weight#of#uranium.####PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP#4.#Which#of#the#following#processes#is/are#endothermic?#i. A#system#absorbs#50#kJ#of#heat#from#the#surroundings#and#does#30#kJ#of#work#on#the#surroundings.#ii. A#system#releases#55kJ#of#heat#into#the#surroundings#and#45#kJ#of#work#is#done#on#the#system.##iii. q#=#12.5#kJ,#w#=#–#3500#J##HINT:#Calculate#ΔE#=#q#+#w#####Draw#pictures#using#a#box#to#represent#the#system#and#use#arrows#to#show#if#energy#is#going#into#the#system#or#out#of#the#system.##PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP## #Fall CHEM 110 Recitation 2 PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP#5.##Rank#these#in#order#of#increasing#electrostatic#potential#energy.##I# an#electron#that#is#2.8#nm#from#a#+2#cation#II# an#electron#that#is#2.8#nm#from#a#P2#anion#III# an#electron#that#is#2.8#nm#from#a#proton#A.## I#<#III#<#II#B.## I#=#II#<#III#C.## II#<#III#<#I#D.## II#<#I#<#III#E.## III#<#II#=#I# # # # # #