Find the volume needed to prepare a 0.694 m pb(no3)2 solution if you start with 110 g of pb(no3)2

0.479 dm^3 (or 479 cm^3)

Explanation:

First, calculate the no. of moles in 110g of Pb(NO3)2.

According to the periodic table, molar mass of Pb is 207.2, N is 14,0, O is 16.0

so, the molar mass of Pb(NO3)2 = 207.2 + (14.0 + 16.0 x 3) x 2 = 331.2

With the formula:

no. of moles = mass/molar mass

no. of moles in 110g of Pb(NO3)2 = 110 / 331.2

= 0.33213 mol

Then, with the formula:

molarity = no. of moles / volume

0.694 = 0.33213 / v

v = 0.479 dm^3 (or 479 cm^3)

Therefore, the volume needed is 0.479 dm^3 (or 479 cm^3)

5.4 days (6 days)

Step-by-step explanation:

First set up an equation. (x represents days)

5 dollars a day = 5x ; Already has 45 = +45 ; Needs 72 = =72

That means your equation is...

5x + 45 = 72

Now solve for x.

5x = 27          Subtract 45 from both sides.

x = 5.4          Divide both sides by 5.

This means he will have to work for at least 6 days.

I hope this helped. :)   (I love these kinds of problems!)