Chemistry help ... table?

Question

solute | mass solute| mol solute | vol solution | molarity

KNO3 | 22.5 g | a)______ | 125.0 mL |b)_____

NaHCO3 | c)______ | d) _______ | 250.0 mL | 0.100 M

C12H22011 | 55.38 g | e) _______ | f) ______ | 0.150 M

WHOAAA, I'm soo confused.. PLease explain answers so I can understand in the future. thanks

Answer 1

KNO3 is potassium nitrate with a molecular weight (mw) of 101.1g/mole.  

You have 22.5g of this.

22.5g / 101.1g/mole = 0.223 moles a) = 0.223 moles

0.223mole / 0.125L = 1.78M   b) = 1.78M

NaHCO3 is sodium bicarbonate with a mw of 84.01g/mole

You have 0.250L of 0.100M solution.  O.250 x 0.100 = 0.025 moles of solute.   d) = 0.025

0.025moles x 84.01 g/mole = 2.10g     c) = 2.10g

C12H22O11 is sucrose with a mw of 342.3g/mole

You have 55.38g of this.

55.38g / 342.3g/mole = 0.162 moles.  e) = 0.162moles

0.162moles / 0.150M = 1.08L f) = 1.08L

Remember:

Molecular weight of compound = mass / no. of moles

Molarity of solution = no. of moles of solute / volume (in L)

Feel free to email me if you need more help.