已知某KOH样品中含水7.62%,含K2CO32.23%,含KOH 90%。现将1.00g样品加入46.00mL1.00mol/L的盐酸中,过量的酸用1.070mol/L KOH溶液刚好中和。蒸发溶液,蒸发到无水时,可得到固体的质量约为
A.3.00g
B.3.43g
C.4.50g
D.无法计算
答案:B
由题意可知,不管溶液中发生如何反应,最后得到的溶质固体是氯化钾。只需求出溶液中有多少物质的量的盐酸就有多少氯化钾,即46×0.001×(39+35.5)=3.427 g. 所以选B。
已知某KOH样品中含水7.62%,含K2CO32.23%,含KOH 90%。现将1.00g样品加入46.00mL1.00mol/L的盐酸中,过量的酸用1.070mol/L KOH溶液刚好中和。蒸发溶液,蒸发到无水时,可得到固体的质量约为
A.3.00g
B.3.43g
C.4.50g
D.无法计算
答案:B
由题意可知,不管溶液中发生如何反应,最后得到的溶质固体是氯化钾。只需求出溶液中有多少物质的量的盐酸就有多少氯化钾,即46×0.001×(39+35.5)=3.427 g. 所以选B。
Passage Two
Which of the following statements is true of what you’ve heard
A.The speaker’s father set out to round up their cattle.
B.The speaker did not dare to chase the cow there any more.
C.The speaker’s horse died in three days.
D.The cow was found dead down the valley days later.