Chemistry

Question 1

Which elements on the periodic table can H-bond?

Answer 1

N, O, F

Question 2

Whats the pH with 0.01M HCl?

Answer 2

10^-2

pH = 2

Question 3

Whats the geometry of CH4

Answer 3

Tetrahedral

4 bonds with no lone pairs

Question 4

In a fractional distillation reaction, which type of molecules will elute first?

Answer 4

Molecules that have smaller boiling points.

Question 5

More (polar/nonpolar) functional groups will give the molecule a higher boiling point

Answer 5

POLAR GROUPS

C=O

OH

Question 6

An ebulliator is a portion of a fractional distillation aparatus that sends mini air bubbles into the distillation flask. Why do you think it does this and what else does it relate to?

Answer 6

It relates to boiling chips at atm pressure!

The air bubbles break the surface tension of the liquid being heated and prevent superboiling and bumping

Question 7

A molecule that is in different orientations (+) and (-) will differ in which area (if it has one)?

Answer 7

The chiral carbon center only

Question 8

What is a boiling point? How do the variables in the BP equation relate to one another?

Answer 8

When the vapor pressure of a liquid equals the surface pressure

BP: VP = Surface Pressure

VP increases as the temperature increases SOOOOOOO

if the surface pressure decreases, the BP of a liquid decreases

Question 9

If there is a leak in a filtration distillation experiment, what happens to the overall BP of the liquids?

Answer 9

If there is a leak = the surface pressure increases

If the surface pressure increases = the VP wants to also increase (meaning temperature is increasing) and the BPs will increase

Question 10

A solution contains 7.15g Na2CO3 x 10H2O (MM 286.14) dissolved in enough water to make 50mL of a green solution. How many sodium ions are in the initial 50mL solution?

Answer 10

7.15g/286.14 = 0.0250

Each mol of Na2CO3 contains 2 mol of Na+

So there are 0.05 mol of Na+

(0.05mol Na+)(6.02x10²³ ions/mol) = 3.01 x 10²² ions

Question 11

If you mix Na2CO3 with water, what forms?

Answer 11

In water, carbonate will undergo:

CO₃^2- + H2O –> HCO3^- + OH^-

Question 12

6. 57g of NiSO4 (MM 262.84)
7. 15g of NaCO3 (MM 286.14)

Whats the max number of moles of NiCO3 that can form?

Answer 12

6. 57/262.84 = 0.025 mol
7. 15/286.15 = 0.025 mol

So the max number is 0.025mol

Question 13

Why does Nickel (II) ion produce a blue color?

Answer 13

It has a partial d orbital.

Lower energy d orbitals absorb visible light to move to higher energy d orbitals

Question 14

T/F

A compound is a stronger ACID when there is hydrogen-bonding for stabilization

Answer 14

TRUE

Question 15

In thin layer chromatography,

will a polar compound or a nonpolar compound have a higher Rf?

Answer 15

A nonpolar compound will have a higher Rf since it will travel up the farthest. Polar compounds will stick to the silica plates (which are also polar) and wont be able to travel as far.