Calculate the pH of solutions prepared by:
(a) Dissolving 4.8 g o...

Question

Calculate the pH of solutions prepared by:
(a) Dissolving 4.8 g of lithium hydroxide in water to give
250 mL of solution.

Accepted Answer

Hello everyone. So this video won't go ahead. Find the ph of a solution that contains K. O. H. And of course H 20. So here's how we'll go ahead and solve this problem, we'll do a step by step breakdown. So first when you go ahead and find the more clarity of K. O H. And then we can go ahead and find the concentration of O. H minus. Then with that concentration we can go ahead and find the P. O. H. Value. And with the P. O. H value can go ahead and find what we ultimately need to find. Which is of course the P. H. So first of course we need the molar mass of K. O. H. So we use the honey dandy puree table to sell for this. So here again we're solving for the molar mass of K. O. H. And this is equal to 56. g per moles. Now with this information we can go ahead and solve for the polarity of K O H. Alright, so this is a bunch of just dimensional analysis. So starting off with the mass of K. O H. S given that's 1.45 g of K. O. H. And the solution amount is mL of solution. So first we're gonna go ahead and convert the volume of solution into, we need the leaders of solutions. So right now we're in male leaders so we can go ahead and do a direct conversion. So for every 1000 ml we have one leader now working with the grams of K. O. H, we want to convert this into moles, so we're gonna go ahead and use the molar mass. So for every one mole of K. O. H, this gives us 56.1083 g of K. O. H. So we see here that the grams of qh cancels our milliliters of solution cancels. And this simply leaves us with the the units of concentration, which is most over leaders. So once you put that into my calculator, we see that the morality of K. O. H is equal to 0. molars. So we know that K. O. H. Is a strong base. So it will dissociate completely. This dissociation equation is K. O. H. Associate into R. K. Plus and O H minus. So this means then that my concentration of O H minus will equal to my concentration of K. O. H, which is then equal to 0.568 molars. So basically we did find the concentration of O. H minus, which means we can go ahead and find our P. O. H. So for my discussion score down from our space. So to solve for my P. O. H, we have an equation that is equal to that the negative log of the concentration of O. H minus will give us the P. O. H. Of course we know this concentration. So we'll just go ahead and plug in this value. So now we're taking the negative log 0.568. So once you put it into a calculator receipt that my P. O. H. Value is equal to 1.246. And lastly we can go ahead and now find our ph value. So my P. H. Plus my P. O. H. Is equal to 14 is how they both relate resolving again for our ph which is then equal to adjust 14 minus R. P. O. H. We know the value of P. O. H. So let's go ahead and plug that into the equation. That's 1.246. So once I put that into my calculator may see that my P. H. Is equal to 12.754. So this is going to be my final answer for this problem. Thank you all so much for watching.

Calculate the pH of solutions prepared by: (a) Dissolving 4.8 g of lithium hydroxide in water to give 250 mL of solution.

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