contestada

What is the molarity of 90.0 g of NH4Cl dissolved to make 2.25 L of solution?

Respuesta :

Answer:

The correct answer is 0.748 M.

Explanation:

To solve this problem, we first need to figure out how many moles of NH4Cl is equivalent to 90.0 g.  To do this, we must find the molar mass of NH4Cl.

14.01 + 4(1.008) + 35.45 = 53.49 g/mol NH4Cl

Now, we can use the molar mass as a conversion factor to convert the 90.0 g of NH4Cl into moles.  This is modeled below:

90.0 g NH4Cl * (1 mole NH4Cl/53.49 g NH4Cl) = 1.68 moles NH4Cl

Now, we must find the concentration or molarity of the solution.  To do this, we must divide the number of moles of solute by the number of liters of solution.  This is shown below:

Concentration (M) = Moles solute/Liters solution

Concentration = 1.68 moles / 2.25 L

Concentration = 0.748 M

Therefore, the correct answer is 0.748 M (note that our answer has 3 significant figures because both of our given values also had three significant figures).

Hope this helps!