配制75%乙醇溶液500ml,需用多少95%乙醇
A.325ml
B.355ml
C.395ml
D.425ml
E.455ml
1.配制75%乙醇溶液100ml,需95%乙醇A.97mlB.80mlC.65mlD.79mlE.60ml
2.用95%和45%的乙醇配制75%的乙醇溶液500ml,应取95%和45%的乙醇各A.250ml,250mlB.260ml,240mlC.300ml,200mlD.245ml,255mlE.350ml,150ml
3.配制75%乙醇溶液100ml,需95%乙醇A.60mlB.75mlC.80mlD.79mlE.85ml
4.用95%和45%的乙醇配制75%的乙醇溶液500ml,应取95%和45%的乙醇各多少毫升A.250ml,250mlB.200ml,300mlC.300ml,200mlD.225ml,275mlE.275ml,225ml
第1题:
第2题:
第3题:
第4题:
第5题: