If a student is told they have a 3.5 M HF solution and they pour out 0.05 L of the solution, what is the number of moles of HF that are present in the solution?

Number of moles of solute = 0.175 mol

Explanation:

Given data:

Molarity of HF solution = 3.5 M

Volume of solution = 0.05 L

Number of moles of HF in solution = ?

Solution:

Formula:

Molarity = number of moles of solute / Volume of solution in L

Now we will put the values in above given formula.

3.5 M = number of moles of solute / 0.05 L

3.5 M × 0.05 L =  Number of moles of solute

         M = mol/L

Number of moles of solute = 0.175 mol

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3