Answer:
Physical Change
Explanation:
Because the filter is removeing the dust by having the air go though a thin material.
Hope it helps!
Acids are chemicals with a pH less than 7 that can donate a proton or H+ ion in a reaction. Bases have a pH greater than 7 and can accept a proton or produce an OH- ion in a reaction. If you mix equal amounts of a strong acid and a strong base, the two chemicals essentially cancel each other out and produce a salt and water. Mixing equal amounts of a strong acid with a strong base also produces a neutral pH (pH = 7) solution. This is called a neauturization and looks like
HA + BOH → BA + H2O + heat
The conclusion that was drawn from the results of the
gold foil experiment is that electrons in an atom are located in specific
shells. The answer is number 4. Also, he concluded that an atom was not an
empty space but rather, the electrons are scattered.
Answer:
NH₄Cl (aq) + NaOH (aq) -> NaCl (aq) + H₂O (l) + NH₃ (g)
(NH₄)₂CO₃ (aq) + 2KOH (aq) -> K₂CO₃ (aq) + 2H₂O (l) + 2NH₃(g)
NH₄NO₃ (aq) + LiOH (aq) -> LiNO₃ (aq) + H₂O (l) + NH₃ (g)
Explanation:
The gas liberated when an alkali reacts with an ammonium salt is NH₃ (ammonia), not CO₂.
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.
