富马酸亚铁中砷盐的检查：取待测品0.50g，加入无水碳酸钠0.5g，混匀，加溴试液4ml，置水浴上蒸干后，在500～600℃炽灼2小时，自然冷却，残渣加溴-盐酸溶液10ml与水15ml使溶解，移至蒸馏瓶中，加酸性氯化亚锡试液1ml，蒸馏，流出液导入贮有水5ml的接收器中，至蒸馏瓶中剩5ml时，停止蒸馏，馏出液加水适量使成28ml，按古蔡法检查砷盐。
加入含砷浓度为1μg/ml的标准砷溶液2ml。在该测定条件下，砷盐的限量是（）.
A.0.0002%
B.0.0004%
C.0.001%
D.0.002%
E.0.004%
F.0.005%
参考答案：B
| 完形填空。 | ||||
| I grew up poor - living with six brothers, my father and a wonderful mother. We had 1 money and few worldly goods, but plenty of love and attention. I was 2 and energetic. I understood that no matter how poor a person was, they could 3 afford a dream. My dream was to be a 4 . When I was sixteen, I could crush a baseball, throw a ninety-mile-per-hour fastball. I was also 5 : my high - school coach was Ollie Jarvis, who 6 me the difference between having a dream and showing strong belief. One particular 7 with him changed my life forever. It was a summer and a friend recommended me for a summer 8 . This meant a chance for my first income - cash for a new bike and new clothes, and the 9 of savings for a house for my mother. The opportunity was attracting, and I wanted to 10 at it. Then I realized I would have to 11 summer baseball to handle the work schedule, and that meant I would have to tell Coach Jarvis I wouldn't be playing. I was 12 about this. When I told Coach Jarvis, he was as 13 as I expected him to be. "You have your whole life to work," he said. "Your 14 days are limited. You can't afford to waste them." I stood before him with my head 15 , trying to think of how to explain to him why my dream of buying my mom a house and having money in my pocket was worth 16 his disappointment in me. "How much are you going to make at this job?" he demanded. "$ 3.25 an hour," I replied. "Well, is $ 3.25 an hour the price of a 17 ?" he asked. That 18 laid bare for me the difference between wanting something right now and having a goal. I devoted myself to 19 that summer, and within the year I was offered a $ 20,000 contract. I signed with the Denver Broncos in 1984 for $ 1.7 million, and bought my mother the 20 of my dreams. | ||||
|