10分! chem question f4!

用戶11549

2008-05-17 6:43 pm

Q1. which of the following solutions has the highest concentration of ions?

A. 1 M ammonia solution
B. 1 M ethanoic acid
C. 1 M hydrochloric acid
D. 1 M sulphuric acid

Q2. Which of the following solutions contains the greates number of ions?
A. 60(cm3) of 0.1 M Na3PO4
B. 60 (cm3) of 0.1 M K2SO4
C. 90 (cm3) of 0.05 M KNO3
D. 120(cm3) of 0.05 M AgNO3

Q3. 1 mole of magnesium chloride and 1.5 moles of sodium chloride are dissolved in water and the solution is made up to 700(cm3). The concentration of the chloride ions is
A. 0.0036M
B. 0.005 M
C. 3.6 M
D. 5.0 M

列埋step呀!!!唔該哂!
唔記得左點計d ion
thx a lot :d

回答 (1)

[匿名]

2008-05-17 11:31 pm

✔ 最佳答案

1. D
Both ammonia solution and ethanoic acid are only partly ionized in water, while hydrochloric acid and sulphuric acid are strong acid, they both completely ionized in water. And since they have same concentration, and hydrochloric acid is only monobasic while sulphuric acid is dibasic. So, sulphuric acid will give out 3 moles of ions, while hydrochloric acid will only give out 2 moles of ions.

2. A
In 60(cm3) of 0.1 M Na3PO4, there is (60/1000)*0.1*4 mole of ions
In 60 (cm3) of 0.1 M K2SO4, there is (60/1000)*0.1*3 mole of ions
In 90 (cm3) of 0.05 M KNO3, there is (90/1000)*0.05*2 mole of ions
In 120(cm3) of 0.05 M AgNO3, there is (120/1000)*0.05*2 mole of ions
By calculation, in 60(cm3) of 0.1 M Na3PO4, there is greates number of ions.

3. D
There is 2 mole of chloride ions in 1 mole of magnesium chloride and 1.5 moles of chloride ions in1.5 moles of sodium chloride. So, there is 3.5 moles of chloride ions in 700(cm3) of the solution. The concentration = (3.5/700)*1000 = 5.0 M

參考: 自己

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