please help!!

The concentration of sodium hydroxide is 1.0 M and the concentration of crystal violet is 1.00E-5 M. identify the limiting reagent and calculate how much of the excess reagent remains after the reaction runs to completion.

Question

please help!!

The concentration of sodium hydroxide is 1.0 M and the concentration of crystal violet is 1.00E-5 M. identify the limiting reagent and calculate how much of the excess reagent remains after the reaction runs to completion.

adamconner · Answer

this is all I'm given. how do i find the balanced equation?

wolfe8 · Answer

You can look those compounds up for the formulas. Then you can look at the ions and write the products yourself.

adamconner · Answer

is this right? found it on google C25N3H30Cl + NaOH = C25N3H30OH + Na + Cl

wolfe8 · Answer

Looks right to me. But wouldn't the Na and Cl combine?

adamconner · Answer

yea, so C25N3H30Cl + NaOH = C25N3H30OH + NaCl.

now how do I find the limiting reagent since its in Molarity. usually I do it when its in grams

wolfe8 · Answer

Use the formula n=mV where n is the number of moles, m the molarity and V is volume.

adamconner · Answer

so I have mol and M and I find V? and then I do volume=g/mol?

wolfe8 · Answer

No you need n, number of moles to find the limiting reagent. Are you given the volume?

adamconner · Answer

ooh, no I am not

wolfe8 · Answer

Hmm then I think we will assume we have 1L of each solution. Have you balanced the equation?

adamconner · Answer

ok, I believe it is balanced

wolfe8 · Answer

So since we know the ratio is 1:1:1:1, and crystal violet is less than NaOH, crystal violet will be the limiting reagent. Because it will run out first and the reaction will have to stop.

adamconner · Answer

aha! yea thats right. why didnt i think of that. -_-

wolfe8 · Answer

Yup and NaOH is called the reagent in excess. Can you do it from here?

adamconner · Answer

well now how do we calculate how much of the excess remains?

wolfe8 · Answer

Well, you will use the violet and NaOH at the same rate since the ratio is 1:1. So when all 1.00E-5 moles of the violet is used up, the same amount of NaOH is used up. So can you find the excess?

adamconner · Answer

so 1-1.00e-5?

wolfe8 · Answer

Yup. :)

adamconner · Answer

that wasn't too bad. But thanks anyway!! :)

wolfe8 · Answer

You're welcome. Also, if the ratios are not 1:1, then you will have to divide the number of moles with their respective coefficients.