A 25. 00 mL sample of unknown Fe3+ and Cu2+ required 16. 06 mL of 0. 050 8
mol·L-1Pb2+to reach an endpoint using xylenol orange. Find the concentration of Cu2+in the unknown.
mol·L-1Pb2+to reach an endpoint using xylenol orange. Find the concentration of Cu2+in the unknown.
第2题
A.50
B.100
C.200
第3题
A.400ml
B.200ml
C.600ml
D.800ml
E.1000ml
第4题
A.186º23′18″
B.186º23′42″
C.186º24′06″
D.186º24′48″
第6题
A.free of
B.within
C.for
D.with
第7题
A.implication
B.sample
C.reference
D.dictionary
第9题
A sample of D-ribose(C5H10O5) with mass 0. 727 g was weighed into a calorimeter and then ignited in presence of excess oxygen. The temperature rose by 0.910 K when the sample was combusted. In another separated experiment in the same calorimeter the combustion of 0. 825 g of benzoic acid,for which the ΔcUΘm= 3251 kJ·mol-1,gave a temperature rise of 1.940 K. Calculate the ΔrUΘmand ΔrHΘmof D-ribose combusted.