Question

In the laboratory you dissolve 22.0 g of nickel(II) nitrate in a volumetric flask and add water to a total volume of 125

mL.
What is the molarity of the solution?

Answer 1

1.364 M.

Step-by-step explanation:

Molarity formula: M= n/v, where n is moles of solute, and v is liters of solution.

Now, we need to convert the grams of nickel to moles and the volume of water to liters.

125mL/1000= 0.125 L.

To convert nickel grams to moles, we need to take a look at it's chemical formula, which is:

`Ni(NO_(3) )_(2)`

Now we count how many molecules of each element we have:

Ni= 1

N= 2

O= 6

Calculate the weight (g) of each element (the values of g/mol can be found on the periodic table and they may vary slightly between one table and the other):

Ni: (1) (58.6934)= 58.6934

N= (2) (14.007)= 28.014

O= (6) (15.999)= 95.994

Sum all the values to obtain the total weight of 1 mole of this compound:

58.6934+28.014+95.994= 129(g/mole)

Now that we know the that 129 grams equal 1 mole of nickel(II) nitrate, we can convert the 22.0 g to moles:

129g ------- 1 mole

22.0g ----- x

x= (22*1)/129= 0.1705 moles.

Now, we have all the values needed to calculate the molarity of this solution. All we have to do is substitute the values in the formula:

M= (0.1705 moles) / (0.125 L)= 1.364 M.