Au2S is =<u><em> 426 g/mol</em></u> for molar mass
Intermolecular force for solids is high. Whereas low in gases. The smell of agarbatti spreads immediately because the molecules of air diffuses very fastly.
If the Ka of HCN = 5.0 x 10^-10
Since
(Ka) (Ka) - 1 x 10^ -14
then
the Kb of its conjugate base (CN-) = 2.0 X 10^-5
since
pH + pOH = 14
when the pH = 10.00
then
the pOH = 4.00
& the OH-
would then equal 1.0 X 10^-4
NaCN as a base does a hydrolysis in water:
CN- & water --> HCN & OH-
notice that equal amounts of OH- & HCN are formed
Kb = [HCN] [OH-] / [CN-]
2.0 X 10^-5 = [1.0 X 10^-4] [1.0 X 10^-4] / [CN-]
[CN-] =(1.0 X 10^-8) / (2.0 X 10^-5)
[CN-] = (5.0 X 10^-4)
that's 0.00050 Molar
which is 0.00050 moles in each liter of aqueous KCN solution
which is
0.00025 moles KCN in 500. mL of aqueous KCN solution
use molar mass of KCN, to find grams:
(0.00025 moles KCN) (65.12 grams KCN / mole) = 0.01628 grams of KCn
which is 16.3 mg of KCN
& rounded to the 2 sig figs which are showing in the Ka of HCN , "5.0" X 10^-10
your answer would be
16 mg of KCN
sorry even after making a correction in calcs , I don't get one of your answers.
the only way that I could get one of them is to pretend that yours was a 1 sig fig problem,
in which case your 16 mg would round off to 20 mg.
but you have 3 sig figs in "500. ml", & 2 sig figs in both the "pH of 10.00."
& The Ka of HCN = "5.0 x 10^-10."
it does however take 12 mg of NaCN, to make 500. mL of aqueous solution pH of 10.00. the molar mass of NaCN has the smaller molar mass of 49.00 grams per mole.
maybe they meant NaCN, but wrote KCN instead.
I hope i answered this correctly for you.
Answer:
Number of moles = 2 mol
Explanation:
Given data:
Mass of carbon = 24 g
Number of moles = ?
Solution:
Formula:
Number of moles = mass/ molar mass
Molar mass of carbon is 12 g/mol.
Now we will put the values in formula.
Number of moles = 24 g/ 12 g/mol
Number of moles = 2 mol
Answer:
A. Hot water increases the collision rate of the molecules, causing the
reaction to occur faster.
Explanation:
Hot water molecules move faster than cold water molecules.
