Can someone please help me with this my final is tomorrow.?

Question

1.what is the molarity of a solution that contains 125g NaCl in 4.00 L solution?

2. what is the molarity of a solution that contains 0.202 mol KCl in 7.98 L solution?

3. the solubility of gases in liquids.....
a. always increases with increasing pressure
b. sometimes increases with increasing presure
c. always decreases with increasing pressure
d. does not depend on pressure

Answer 1

Answer for 3 is always decreases with increasing temperature.

Sorry, I read it wrong...I will not change answer...in terms of temperature the answer is correct.

Answer 1 is 0.535 M

NaCl MW is 58.44

(MW of Na = 22.990 gm/mole. MW of Cl = 35.453 gm/mole. MW of NaCl = 58.443 gm/mole)

So 58.44 g of NaCl when dissolved in 1 Liter of water gives ! M solution.

To find out the Molarity of solution for 125 g of NaCl in 45 L of solution,

(125 g x 1 M x 1L) / (58.4 g x 4 L) = 0.535 M



Answer 2 is 0.0251 M


KCl MW is 74.55

(MW of K = 39.098 gm/mole. MW of Cl = 35.453 gm/mole. MW of KCl = 74.551 gm/mole)

Since 1 mole of KCl = 74.55 g

0.202 mole of KCl = 14.91 g of KCl

Now as before,. you have solution of 14.91 g of KCl in 7.98 L of water and you want to know its molarity.

Knowing that 74.55 g of KCl in 1 L gives 1 M Solution,

(14.91 g x 1 M x 1L) / (74.55 g x 7.98 L) = 0.0251 M

Answer 2

1. Molarity is moles NaCl in liters of solution. This is a two-part answer, so you use two parts of the given in the first step:

125gNaCl/4.00Lsoln x 1molNaCl/58.5gNaCl = 125/(4.00)(58.5) =

At. wts.: Na = 23 Cl = 35.5 The multiplication cancels gNaCl, leaving molNaCl. The units of liters in the denominator were already in the given.

2. By the same token: 0.202molKCl/7.98Lsoln = mol/L

3. a. Increases with increasing pressure. Once you uncap a bottle of Coke, thus releasing the pressure, you can see the solubility of CO2 decrease, as it first goes *poosh!* and then releases bubbles slowly with time..

Answer 3

Some help with the first two then...

1. Convert grams NaCl to moles NaCl then divide by volume in liters.

2. You have moles already...divide by Liters

if this is foreign or gobbledygook, you're in trouble....

Answer 4

uhmmmmm..... next question pls......