【問題】英文化學題...體積/重量克分子濃度

[*starfish* 10]

sorry >"<是英文的化學題

Concentrated sulfuric acid (18.4-molar H2SO4) has a density of 1.84 grams per milliliter. After dilution with water to 5.20-molar, the solution has a density of 1.38 grams per milliliter and can be used a san electrolyte in lead storage batteries for automobiles.

a) Calculate the volume of concentrated acid required to paper 1.00 liter of 5.20-molar

H2SO4

b) Determine the mass percent of H2SO4 in the original concentrated solution

c) Calculate the volume of 5.20-molar H2SO4 that can be completely neutralized with 10.5 grams of sodium bicarbonate, NAHCO3

d) What is the molality(體積克分子濃度) of the 5.2-molar H2SO4 ?

----> 濃縮的H2SO4的體積克分子濃度是18.4

密度是1.84 g/mL

在經過稀釋後的體積克分子濃度是5.20

溶液的密度是1.38 g/mL

*H2SO4的分子量是98

[冬天 10]

a)5.2M, 1L的硫酸(aq)有5.2莫耳的硫酸分子(H2SO4)

　設αL, 18.4M的硫酸(aq)有5.2莫耳硫酸分子

　1 X 5.2 = 18.4 X α

　α = 0.282(L)

b)18.4M的硫酸1L重1840公克

18.4莫耳的硫酸分子的質量 = 18.4 X 98 = 1083.2(公克)

故18.4M的硫酸(aq)中硫酸的重量百分比為 (1083.2 / 1840) X 100% = 98%

c)10.5公克的sodium bicarbonate 有β莫耳

β = 10.5 / 84 = 1 / 8 = 0.125

因為酸檢中和時弱酸/鹼可視為完全解離

故β莫耳的sodium bicarbonate 溶於水會搞出β莫耳的OH¯

需β/2莫耳的硫酸即可中和

設需γL

0.0625 = 5.2 X γ

γ = 0.012(L)

d).....

老實說這一題我覺得怪怪的

我的認知是

Molality = 體積莫耳濃度 = 上面所寫的"M" = (溶質莫耳數) / 溶液體積(unit:L)

molality = 重量莫耳濃度 = 台灣學生說的"m" = (溶質莫耳數) / 溶劑重量(unit:kg)

麻煩確認一下喔

假設他是重量莫耳濃度

1L的該溶液重1380g

其中含5.2莫耳的硫酸重5.2 X 98 = 509.6(g)

水重870.4g

所以重量莫耳濃度 = 5.20 / 0.8704 = 5.97

好久沒碰化學

應該不會錯吧

[*starfish* 10]

sorry >"< molality是"重量"克分子濃度 我寫錯了sorry

謝謝你 = ) 我想你算對了喔 :)

[pingu1 10]

molarity=M(體積莫耳)

molality=m(重量莫耳)

似乎是這樣的

[pingu1 10]

a

[楓影霜 10]

molarity=M(體積莫耳)

molality=m(重量莫耳)

似乎是這樣的

沒錯

這樣才是正確的:p