[化學] 幾題化學

看板TransBioChem作者 (夏天的風)時間15年前 (2011/05/04 00:13), 編輯推噓3(306)
留言9則, 2人參與, 最新討論串1/1
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) 我想問的是 我用C:H = 55/44 : 22.5x2/18 = 1:2 但是我不會算說要怎麼知道答案是(2)還是(4) 有版友可以指點迷津嗎? 謝謝 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 可是我覺得是false 因為算原子重量不是應該用原子量(atomic weight)算嗎? 12.01g 為什麼會是原子序? 原子序不是代表原子有幾個質子+中子的意思嗎? 還是我觀念有錯 請版友指正 謝謝 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 111.184.171.40

05/04 00:59, , 1F
mass number是指"質量數"=質子數+中子數
05/04 00:59, 1F

05/04 01:00, , 2F
atomic number原子序:指的是原子裡面他所具有質子數
05/04 01:00, 2F

05/04 01:19, , 3F
樓上第2題..正解..第一題只要把CHO實際的重量算出來
05/04 01:19, 3F

05/04 01:21, , 4F
算出C:15mg H:2.5mg O:4mg
05/04 01:21, 4F

05/04 01:23, , 5F
在除上原子量 C:H:O=15/12: 2.5/1 : 4/16
05/04 01:23, 5F

05/04 01:24, , 6F
乘上最小公倍數48..得C:H:O=60:120:120=5:10:1
05/04 01:24, 6F

05/04 01:25, , 7F
樓上更正是..................60:120:12..
05/04 01:25, 7F

05/04 01:27, , 8F
實際重量忘了說怎麼算= =..C:55X (12/44 )
05/04 01:27, 8F

05/04 01:27, , 9F
H= 22.5X (2/18)=2.5 O=21.5-15-2.5=4mg...
05/04 01:27, 9F
文章代碼(AID): #1Dm2csoq (TransBioChem)