Question

Help, just need an explanation on how to start this.

With what volume of 5.00M HF will 4.80g of calcium hydroxide react completely, according to the following reaction?

2HF + Ca(OH)2 ---> CaF2 + 2H2O

Answer 1

do you know how to do regular stoichiometric problems?

Answer 2

Yes

Answer 3

okay, so you need to convert the mass of \(Ca(OH)_2\) given to moles, then find how many moles of HF you need to react with that (in terms of the coefficients). The use the molarity formula to find the volume you need.

Answer 4

you find only the moles of HF or even the mass of HF?

Answer 5

this is what i did:
4.80 g (1 mole Ca(OH)2 / 74.1g Ca(OH)2) and got 0.06 moles

Answer 6

0.06 moles Ca(OH)2 (2 moles HF/1 mole Ca(OH)2)

Answer 7

thats good. so you found \(n_{HF}\), now find the volume using the molarity formula.

Answer 8

so M would equal 0.12 in this case (0.06 * 2 mol HF = 0.12)?

Answer 9

M is given in the question

\(5 M=\dfrac{0.12~moles}{L}\)

Answer 10

Ohhh!!!! I kept thinking M = grams/L -_-

Answer 11

that's density.. oops

Answer 12

haha nope. mol/L

Answer 13

hah yeah molarity is somewhat like density.

Answer 14

Thank you, oh savior

Answer 15

haha no problem dude