作者spyseagood (夏天的风)
看板TransBioChem
标题[化学] 几题化学
时间Wed May 4 00:13:38 2011
1.
A 21.5 mg sample of a compound composed of carbon(C), hydrogen(H),
and oxygen(O) is perfectly combusted to generate 55.0 mg of carbon dioxide
and 22.5 mg of water. From (1)~(5) below choose the most suitable empirical
formula of this compound.
(1) C3H8O
(2) C4H8O
(3) C4H10O
(4) C5H10O
(5) C5H12O
答案是(4)
我想问的是
我用C:H = 55/44 : 22.5x2/18 = 1:2
但是我不会算说要怎麽知道答案是(2)还是(4)
有版友可以指点迷津吗?
谢谢
2.
The mass of 1 mol of carbon atom 12C whose mass number is 12 is 12.00g.
True or False?
答案是true
可是我觉得是false
因为算原子重量不是应该用原子量(atomic weight)算吗?
12.01g
为什麽会是原子序?
原子序不是代表原子有几个质子+中子的意思吗?
还是我观念有错
请版友指正 谢谢
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◆ From: 111.184.171.40
1F：推 sean56892002:mass number是指"质量数"=质子数+中子数 05/04 00:59
2F：→ sean56892002:atomic number原子序:指的是原子里面他所具有质子数 05/04 01:00
3F：推 nomean0411:楼上第2题..正解..第一题只要把CHO实际的重量算出来 05/04 01:19
4F：→ nomean0411:算出C:15mg H:2.5mg O:4mg 05/04 01:21
5F：推 nomean0411:在除上原子量 C:H:O=15/12: 2.5/1 : 4/16 05/04 01:23
6F：→ nomean0411:乘上最小公倍数48..得C:H:O=60:120:120=5:10:1 05/04 01:24
7F：→ nomean0411:楼上更正是..................60:120:12.. 05/04 01:25
8F：→ nomean0411:实际重量忘了说怎麽算= =..C:55X (12/44 ) 05/04 01:27
9F：→ nomean0411:H= 22.5X (2/18)=2.5 O=21.5-15-2.5=4mg... 05/04 01:27