# writing out Ksp expressions

#### RuSkaya

10+ Year Member
5+ Year Member
When writing out the Ksp expression... do you include exponents?

When taking practice tests, several solutions showed that you leave the exponents out, however when I look the concept up online or in books it shows to leave them in.

for example -

BaF2 (s) --> Ba^2+ (aq) + 2F-

Is the Ksp = [Ba^2+] [F-] or Ksp = [Ba^2+] [F-]^2

Thanks!

#### RuSkaya

10+ Year Member
5+ Year Member
nvm sorry I'm pretty sure the solution I saw that left out the exponent was a typo

#### ksmi117

##### GEAUX TIGERS!!!
Moderator Emeritus
10+ Year Member
7+ Year Member
That's gotta be a typo. The exponents are definitely supposed to be there.

#### RuSkaya

10+ Year Member
5+ Year Member
That's gotta be a typo. The exponents are definitely supposed to be there.
kk thanks!

#### UC pre med

10+ Year Member
5+ Year Member
Pretty sure you have to have the exponents.

Just as a side note, make sure when you do the actual reaction, for whatever you are doing, you put 2x in the F- box and then square that to get 4x^2. Just saying because when I first started doing this stuff, i got like a 50% on a high school chem test for forgetting that one rule.

#### RuSkaya

10+ Year Member
5+ Year Member
Pretty sure you have to have the exponents.

Just as a side note, make sure when you do the actual reaction, for whatever you are doing, you put 2x in the F- box and then square that to get 4x^2. Just saying because when I first started doing this stuff, i got like a 50% on a high school chem test for forgetting that one rule.
yehh I made that mistake on a practice test! I squared the "x" and then forgot to square the 2!