Dr. A!!!!!!!!! MOLARITY,MOLALITY: chemistry?

[livelaughlove001]

i really need help from anyone who knows how. i know its waste of your time but it would help me a whole lot and make a huge difference. i dont know HOW to do these problems. please please please help. dont give me the answer but show me how to do it. im bad at chem. so if you could make it easy it would help alot haha

What would be the molality of 3.40 L of a 0.490 M solution?

What is the molarity of each resulting solution when the following mixtures are prepared?
(a) 590.2 mL H2O is added to 20.0 mL 6.07 M HNO3
(b) 32.0 mL 1.75 M HCl is added to 80.0 mL 0.335 M HCl

Calculate the molality of the following solutions.
(a) 22.9 g NaCl in 103.7 g H2O
(b) 28.9 g CaCl2 in 744.1 g H2O
(c) 2.79 g NaOH in 0.778 L H2O

How many grams of solute are contained in the following solutions?
(a) 71.5 mL 0.0199 M KOH
(b) 182 mL 1.28 M K2SO4
(c) 698.0 mL 0.242 M NH4OH

helppppp please

[Dr.A]

(a) Moles HNO3 = 0.0200 L x 6.07 =0.121
total volume = 610.2 mL = 0.6102 L
M = 0.121/ 0.6102 =0.198
(b) moles HCl = 0.032 x 1.75 =0.056
Moles HCl = 0.080 x 0.335 = 0.0268
total moles = 0.0828
total volume = 112 mL = 0.112 L
M = 0.0828 / 0.112 =0.739

(a) Moles NaCl = 22.9 /58.453 =0.392
m = 0.392 / 0.1037 Kg =3.78
(b) moles CaCl2 = 28.9 / 110.9 = 0.261
m = 0.261 / 0.7441 Kg =0.350
(c) Moles NaOH = 2.79 / 40 g/mol =0.0698
m = 0.0698 / 0.778 = 0.0897 ( since density of water is 1 g/mL)

(a) moles = 0.0715 x 0.0199 =0.00142
mass = 0.00142 x 56 g/mol =0.0797 g
(b)moles = 0.182 x 1.28 =0.233
mass = 0.233 x 174.2 =40.6 g
(c) moles = 0.698 x 0.242 =0.169
mass = 0.169 x 35 = 5.92

I hope this help you

[Caramel]

You are pathetic. Do your own homework, you little loser. I bet your parents are ashamed.