Can anyone solve these two questions?

Question

(1) concentrated phosphoric acid is 85.0 % H3PO4 by mass. The density of the solution is 1.70 g/mL. What volume is required to provide 2.50 grams of H3PO4?
_________en.

(2) What is the maximum yeild of isopentylacetate that can be prepared from 3.58 g of isopentanol and 4.75 g of acetic acid?
___________________g.

Answer 1

First question:

We know that purity of phosphoric acid is 85% so:

2.5 g -------85%
x g -------100%

x = 2.94 g

As we know the density of phosphoric acid we may know what are the volume that contains 2.94 grames:

V = m/Þ = 2.94 g ÷ 1.70 g/mL = 1.73mL

Second question:

In terms of molecular formulas the reaction can be written as follows:

C5H12O......+... C2H4O2 ......-------> C7H14O2 .......+..... H20
(isopentanol)....(acetic acid)..........isopentylacetate

molecular weights of each compound is:

M(isopentanol)=88 g/mol
M(acetic acid) =60 g/mol
M(isopentyl acetate) = 130 g/mol

Let´s see how many moles of each compound are reacting:

3.58 g isopentanol / 88g/mol = 0.04 moles isopentanol
4.75 g acetic acid / 60 g/mol = 0.08 moles acetic

Let´s see how is the ratio of moles of each substance:

0.08 moles isopentanol / 0.04 moles acetic acid = 2

So there is more isopentanol than acetic acid. The maximum yield will be limited by the available amount of acetic acid.

As we see, the reaction is 1:1:1 so, the 0.04 moles of acetic acid just can react with 0.04 moles of isopentanol giving 0.04 moles of isopentylacetate.

0.04 moles isopentyl acetate = 0.04 * (130 g/mol) = 5.2 g of isopentyl acetate is the maximun yield of this reaction.

That's it!

Good Luck!

Answer 2

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Answer 3

(1) 1mL has mass of 1.7g & is 85% H3PO4 so i mL contains 1.7*.75=1.445g H3PO4
need 2.5g H3PO4 so 2.5g/1.445gH3PO4/ml=1.73mL

(2) 3.58g isopentanol=.04068 moles; 4.75g acetic acid=.0792 moles so isopentanol is limiting. if 100% conversion, will get .04068 moles isopentylacetate.
MW= 130g/mole
yield(max)=.04068*130=5.29g

Answer 4

(1) V=2.50 g/1.70 g/mL=1.47 mL

Answer 5

1.73 ml

I'm into maths not chemestry so the other answer is beyond me.

Answer 6

yes.