Test 3: Concentration, Electrolytes and pH

Question 1

What is the concentration of 15g NaCl in 250 mL, in g/L?

Answer 1

60g NaCl/L

Question 2

What is 500mg/L in g/100mL?

Answer 2

0.05g/100mL

Question 3

What is 1L of 10% ethanol in g/L?

Answer 3

100mL/L

Question 4

What is an aqueous solution?

Answer 4

It is when the solvent is water.

*1 mL of water = 1g

Question 5

What’s parts per million (ppm)?

Answer 5

Is is used for really teeny tiny amounts of stuff, for weak concentrations. It is the number of parts of solute in a
1 000 000 parts of solution.

Question 6

What is one ppm equaled to?

Answer 6

1g/1 000 000g
1g/1 000 000mL
1mg/1kg
1mg/1L *aqueous

Question 7

What is 0.14mg/200mL in ppm?

Answer 7

0.7 ppm

Question 8

How many grams/125mL when 5000 ppm?

Answer 8

0.625g

Question 9

0.002% of Ca in ppm and g/L?

Answer 9

20 ppm

0.02g/L

Question 10

0.025g/mL, how many grams in 100mL, 250mL and ppm?

Answer 10

25 000 ppm

2. 5g/100mL
3. 25g/250mL

Question 11

What is molarity (M)?

Answer 11

Molar concentration. mol/L. c=n/v

*n=moles

Question 12

What is M, if 4.5g NaNO3 in 265mL?

Answer 12

0.2mol/L

Question 13

What is the volume, if 10M HCl, using 15.5g HCl?

Answer 13

0.043L

Question 14

What dissolves in water?

Answer 14

Everything dissolves in water.

Question 15

What dissociates?

Answer 15

Ionic bonds.

Question 16

What bonds are electrolytic?

Answer 16

Ionic bonds because they have charges.

Question 17

What bonds are non-electrolytic?

Answer 17

Covalent bonds (they don’t dissociate).

Question 18

What are the three types of electrolytes?

Answer 18

Acids, bases and salts (all salts are neutral).

Question 19

What are acids made up of?

Answer 19

H + non-metal or polyatomic (H + anion)

Question 20

What are bases made up of?

Answer 20

Metal + OH (cation + OH)

Question 21

What are salts made up of?

Answer 21

Metal + non-metal or metal + polyatomic

Question 22

Can electrolytes conduct electricity?

Answer 22

Yes, when dissolved in water.

Question 23

What is the formula for electrolytic dissociation?

Answer 23

Compound —(H2O)—-> charged element(s) + charged element(s)

Question 24

What does more dissociation mean?

Answer 24

More dissociation equals more charges so stronger electrolytes.

Question 25

Formula for acids?

Answer 25

H+ dissociates from the anion. Begins with H and ends with anion.

Question 26

Formula for bases?

Answer 26

OH- dissociates from the cation. Begins with cation and ends with OH.

Question 27

Formula for salts?

Answer 27

Cation dissociates from anion. (They dissociate from each other).

Question 28

How do pH amounts vary?

Answer 28

pH amount varies by a factor of 10.

Question 29

What is the concentration of H+ (in M) for different levels of pH?

Answer 29

0   1
1    10^-1   (0.1)
2   10^-2   (0.01)
3   10^-3    (0.001)
etc...

Question 30

What is the concentration of OH- (in M) for different levels of pH?

Answer 30

0   10^-14
1    10^-13
2   10^-12
3   10^-11
etc...

Question 31

When do we consider the substance a strong acid?

Answer 31

When all or most of the H+ dissociates from the anion.

Question 32

When do we consider the substance a strong base?

Answer 32

When all or most of the OH- dissociates from the cation.