Question

How many moles of solute are needed to prepare 16.0 ml of a 0.415 M Pb(NO3)2, solution?

A .00664
B .0072
C 2.81
D 2.59

Answer 1

0.00664 moles of solute are needed to prepare the solution.

Step-by-step explanation:

Molarity is a unit of concentration based on the volume of a solution and is defined as the number of moles of solute per liter of solution. In other words, molarity is defined as the number of moles of solute that are dissolved in a given volume and is determined by the following expression:

`Molarity (M)=(number of moles of solute)/(volume)`

Molarity is expressed in units
`(moles)/(liter)`.

In this case:

• Molarity= 0.415 M
• number of moles of solute= ?
• volume= 16 mL= 0.016 L (being 1 L= 1000 mL)

Replacing:

`0.415 M=(number of moles of solute)/(0.016 L)`

Solving:

number of moles of solute= 0.00664

0.00664 moles of solute are needed to prepare the solution.

Answer 2

`N_(solute)=6.64x10^(-3)mol`

Step-by-step explanation:

Hello,

In this case, we define molarity as shown below:

`M=(N_(solute))/(V_(solution))`

Whereas we have the moles of the solute and the volume of the solution in litres, in such a way, for finding the moles we solve for it as shown below:

`N_(solute)=M*V_(solution)`

`N_(solute)=0.415(mol)/(L) *16.0mL*(1L)/(1000mL)\\ \\N_(solute)=6.64x10^(-3)mol`

Best regards.