Shared Flashcard Set

Details

Water Section C
solubility curves, pph ppm calculations, like dissolves like
25
Chemistry
10th Grade
11/14/2011

Additional Chemistry Flashcards

 


 

Cards

Term

Define a saturated solution.

 

Use the terms solvent and solute.

Definition
A solution is saturated when the solvent (usually water) has dissolved the maximum amount of solute.
Term
If you want to dissolve a greater amount of salt in a solution, what should you do with the temperature? 
Definition

Since salt is an ionic compound, then raising the temperature will allow you to dissolve a greater amount of salt.

Term
What is the solubility of KNO3 at 35 °C?
Definition

According to the solubility curve, the solubility is

 

55 g of KNO3 in 100 g H2O

 

at 35 °C.

Term
With increasing temperature, the solubility of a gas (increases/decreases).
Definition
decreases
Term

You have 80 grams of 20 ºC water, and 50 grams of KNO3.

 

Explain how you would make a saturated solution of KNO3 with these materials.

Definition

Since the solubility of KNO3 at this temperature is about 30 grams in 100 grams of water, which is equivalent to 24 grams of KNO3 in 80 grams of water, you would measure out 24 grams of KNO3 and dissolve it in the 80 grams of water.

 

 

Term

A saturated solution of NH4Cl made with 100 grams of water, is initially at 90 ºC.

 

You then let the solution cool to 5 ºC.

 

How many grams of NH4Cl will precipitate out of solution at 5 ºC?

Definition

70 g - 30 g = 40 g

 

40 grams will precipitate out.

Term

You think you are in possession of a saturated solution of NaCl.  But you want to be sure.

 

Explain how you could use a single crystal of NaCl to find out.

Definition

Add the single crystal to the solution.  If the crystal does not dissolve, then the solution was saturated.

 

If the crystal does dissolve, then the solution was unsaturated.

Term
Calculate the pph concentration of a saturated solution of potassium iodide at 20 ºC. 
Definition

According to the solubility curve, the solubility at 20 ºC is about 145 g KI/100 g H2O.

 

So, the pph concentration is calculated by dividing the mass of the solute by the total mass of the solution.

 

            145  x          solve for x, get 59 pph

            245     100

Term

A sample of river water is found to have a lead(IV) concentration of 18 ppm.

 

How many grams of lead(IV) ion are in a 450 kg sample of this river water? 

Definition

18 ppm means 18 kg of lead(IV) ion dissolved in 1,000,000 kg of river water sample.  So set up the following ratio:

 

      18      =     x            solve for x, get 0.0081 kg.

 1,000,000      450 kg

 

But since they ask for the grams, 0.0081 kg is 8.1 grams.

Term
If 14 grams of sodium nitrate is dissolved in 75 grams of water, calculate the pph concentration.
Definition

 14  =     x          solve for x, get 15.7 pph.

            89       100

Term
A solution of 80 grams of NH3 dissolved in 200 grams of water at 15 ºC is (saturated/unsaturated/supersaturated).
Definition

Unsaturated.

 

At 15 ºC, the solubility of NH3 is 60 grams per 100 grams of water, which is equivalent to 120 grams per 200 grams of water.

 

Since only 80 grams of NH3 are dissolved, then the solution is unsaturated.

Term

A chemist dissolves 30 grams of potassium chloride in 100 grams of water at 50 ºC.  The solution is unsaturated.

 

How many more grams of solute need to be added to make the solution saturated?

Definition
10 more grams.
Term
A Na+ solution has a concentration of 8 pph.  Describe how mnay grams of solute and solvent are in a 100 gram sample of this solution.
Definition
8 pph means that 8 grams of sodium ion are dissolved in 92 grams of water. 
Term

A solution is classified as a base if the concentration of which ion (H+ or OH-) is greater? 

Definition
OH- concentration is greater.
Term

Name this ion:

 

OH-

Definition
hydroxide ion.
Term

A solution having a pH=6 is classified as a(n)

(acid / base). 

Definition
Acid.
Term
How does the concentration of H+ in solutions with pH values of 4 and 7 compare?
Definition

Since the pH difference is 3, the concentration difference is

 

10 x 10 x 10 = 1000 times difference in concentration.

 

 

Term
Give two examples of heavy metals.
Definition
lead and mercury.
Term
If an unknown clear liquid is miscible with water, the unknown liquid is classified as (polar/nonpolar). 
Definition
Polar.
Term

Salt dissolves in water, but not in acetone. 

 

Therefore acetone is (polar/nonpolar).

Definition
Nonpolar.
Term
Explain why water is a polar molecule.
Definition

Water is a polar molecule because the two bonds in water have unequally-shared electrons.

 

As a result, the molecule has partial charges on it.

 

Term

Draw two water molecules, showing the partial charges on each molecule.

 

Then show a hydrogen bond between the two molecules.

Definition
[image]
Term
Which solute - NaNO3, NH4Cl or or NaCl - has a greater temperature dependence on its solubility? 
Definition
NaNO3.  This solute has the largest slope of the three solubility lines.
Term

Clove oil is a dark brown, denser-than-water nonpolar liquid.

 

If you mix water, CuSO4 and clove oil together, what would the resulting mixture look like?  Discuss colors.

 

 

Definition

The CuSO4 would dissolve in the water, and the clove oil and water/CuCO4 solution would make separate layers, with the clove oil on the bottom.

 

So the top layer would be a clear or slightly blue solution, and the bottom layer would be dark brown.

Supporting users have an ad free experience!