By using the ICE table :

initial 0.2 M 0 0
change -X + X +X
Equ (0.2 -X) X X

when Ka = (X) (X) / (0.2-X)
so by substitution:

4.9x10^-10 = X^2 / (0.2-X) by solving this equation for X
∴X ≈ 10^-6
∴[HCN] = 10^-6

and PH = -㏒[H+]
= -㏒ 10^-6
= 6

3 0

3 years ago

Read 2 more answers

What is the surface area of the given figure?

eduard

Answer:

the answer will be 2,280 cm>2

3 0

2 years ago

How do you figure out how many valence electrons an element has?

Alik [6]

It's how many are in the element's outer layer. The layers go: 2, 8, then 8.

Ex-6 electrons. 1 layer is 2, the next layer has 4 left. If that layer holds 8, you can do 8-4 and it has 4 valence electrons.

Ex-10 electrons. 1 layer is 2, the next layer has 0 left. It has 8 valence electrons because the outermost layer is full with 8.

ex-11 electrons. 1 layer is 2, the next layer is full as well. 2+8=10; it has 1 left. So that element has only one valence electron.

4 0

3 years ago

Read 2 more answers

Please help with 1 chemistry question thank you!

ale4655 [162]

Here are the CORRECT names and molecular formulas

carbonate: $CO_3^{2-}$
bicarbonate: $HCO_3^{-}$

Choice 1 is incorrect

nitrite: $NO_2^{-}$
nitrate: $NO_3^{-}$

Choice 2 is incorrect

sulfite: $SO_3^{2-}$
sulfide: $S^{2-}$

Choice 3 is incorrect

By process of elimination, you can infer choice 4 is correct.

Actually, choice 4 is the only choice that displays the correct name and formula.

Have an awesome day! :)

7 0

3 years ago