问题
选择题
— Where can you see the notice "ALL CLOTHES HALF-PRICE"?
— _____. [ ]
A. In a bank.
B. In a shop.
C. In an office.
D. In a cinema.
答案
答案:B
— Where can you see the notice "ALL CLOTHES HALF-PRICE"?
— _____. [ ]
A. In a bank.
B. In a shop.
C. In an office.
D. In a cinema.
答案:B
(12分)某氢氧化钙中含有碳酸钙杂质,称取研细的该样品12.4g放入锥形瓶中,加入32.6g水,充分振荡形成悬浊液,再向锥形瓶中逐滴滴加盐酸使其充分反应至无气泡产生,测得加入盐酸的质量与锥形瓶中物质的质量关系如下表所示.
加入盐酸的质量/g | 0 | 25 | 37.5 |
锥形瓶中物质的质量/g | 45 | 70 | 80.3 |
(2)反应产生二氧化碳的质量为 g.
(3)求样品中氢氧化钙的质量分数(写出计算过程,精确到0.1%).