1. Which contain the same number of ions as the value of Avogadro's constant?
a. 0.5 mol NaCl
b 0.5 mol MgCl2
c. 1.0 mol Na2O
d. 1.0 mol MgO
2.Assuming complete reaction, which volume of 200mol dm-3 HCI(aq) is required to neutralize 50.0cm3 of 200 mol dm-3 Ba(OH)2 (aq)?
3. What is the concentration of ethanol in the following solution?
A 1L of water-ethanol solution contains 1.5 micro-liters of ethanol
thx anybody help
it is better if the answer is detail and list the procedure
very thx
Chem Problem... thx
2012-01-15 8:04 pm
回答 (2)
2012-01-16 9:38 pm
✔ 最佳答案
1. For 0.5 mol of NaCl, there are 0.5 mol x 2 = 1 mol of ions
Therefore ans = A
2.
Equation of reaction:
2 HCl + Ba(OH)2 => BaCl2 + 2H2O
50.00 cm3
Number of moles of Ba(OH)2 = 200 mol dm-3 x 50 cm3 = 200 mol dm-3 x 0.05 dm3 = 10 mol
Number of moles of HCl required = 10 mol x 2 = 20 mol
Volume required = 20 mol / 200 mol dm-3 = 0.1 dm3 = 500 cm3//
3.
1.5 micro-litre = 1.5 * 10^(-6) L
Therefore, concentration = (1.5 x 10^(-6))/1 = 1.5x10^(-4)%//
2012-01-16 9:30 pm
Here's not for lazy guys to copy for their homework.
One can ask for help on clarifying some topics & difficulties; no one could wait for others to finish the homework for him.
At least you should tell us what's your difficulty.
One can ask for help on clarifying some topics & difficulties; no one could wait for others to finish the homework for him.
At least you should tell us what's your difficulty.
收錄日期: 2021-04-13 18:29:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20120115000051KK00282