can someone explain how to do a mole/molarity problem??

Question

What is the molarity of a solution that contains 250g of NaNo3 in 300ml of solution?

Answer 1

Molarity (moles/liter) is abbreviated M, not to be confused with molality (moles of solute/kg of solvent), which is abbreviated m. Math problems involving moles/molarity aren't too bad at all... all you do is plug in numbers and solve.

Answer 2

use stoichiometry...start with your given over (divided by) 1.

let's say you have 5g of Hydrogen, or H2...you want to find the number of atoms
you know there are 6.022x10^23 atoms in one mole...so you use this in the equation and you start with the given

5g 1 mol 6.022x10^23atoms
____ x ____________ x ________________ = ?
1 (amu H2)g 1 mol

5g/1 is your given
1mol/(amu H2) is the ratio of mol:g of the element...use the mass in the periodic table for this part
and finally 6.02x10^23atoms/1mol is the atom/mol ratio

since your given is given to you in grams, and you want to end up with atoms, make sure every measurement you have on top is on the bottom so they can cancel out...because the only one you want left is "atoms"...if grams or moles end up in your final answer, you did something wrong

it's hard to explain just by typing out...i hope this helped

Answer 3

the answer is 9.8 M
molar mass of NaNO3 = 85g
so moles of NaNO3 = 250/85=2.94
molarity = 2.94/0.3 litres=9.8 M

Answer 4

In order to solve these you need the molar mass of the molecule or compound in question.

Answer 5

divide the amount of moles dissolved in a substance by the volume of the solution.

Answer 6

yes, i can