1.1.2 Basic Principles and Techniques (Expressions of Reagent Concentration) Flashcards

1
Q

Molarity is moles per Kg solvent

Molality is moles per L of solution

T or F

A

F

Molarity = Moles/L
Molality = Moles/Kg

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2
Q

What is the formula for Molarity?

A

M = (g/L) / MW

MW = Molecular weight

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3
Q

IF g/dL is given, what is the formula?

A

M = ((g/dL) / MW) x 10

OR

M = ((g/dL) x 10)) / MW

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4
Q

Equivalent weights per L of Solutions

a. Normality
b. Nomality
c. Nomarity

A

a

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5
Q

Formula for Equivalent weights?

A

EW = MW / Valence

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6
Q

What is valence?

a. Number of Hydrogen
b. Number of hydroxyl (OH)
c. Number of electrons gain or loss (Charge)
d. Both a and c
f. All of the above

A

f

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7
Q

What is the formula for Normality?

A

N or Eq/L

=

(g/L) / EW

EW = Equivalent weight

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8
Q

Amount of solute per 100 total units of solution

a. Dilution
b. % v/w
c. % w/v
d. Normality

A

c

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9
Q

If g/100mL = g/dL

IF Molarity is given
g/dL = (M x MW)/10

IF Normality is given
g/dL = (N x EW)/10

T or F

A

T

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10
Q

Expression of relative concentration

a. Dilution
b. Ratio

A

a

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11
Q

Amount of something relative to another

a. Dilution
b. Ratio

A

b

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12
Q

What is the formula for Dilution?

A

D = SV / TV

OR

D = SV / (SV + DV)

SV = Solute volume
DV = Diluent volume
TV = Total Volume

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13
Q

What is the Molarity of a 1L solution containing 72g of H2O
(H=1, O=16)

A

4

Solution:

Add the Molar mass:
H = 1 x 2 = 2
O = 16 x 1 = 16
16 + 2 = 18
MW = 18

(72g/L) / 18
= 4

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14
Q

What is the Molarity of 0.234 mol of CoCl2 in 0.527 L of solution

A

0.444

Solution:

The Moles is already given just divide it by the solution
REMEMBER: M = Moles/L of solution

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15
Q

What is the molarity of 20.54 g of Al(NO3)3 in 1575 mL of solution/

Al = 26.982
N = 14.007
O = 16.000

A

0.0612 / 6.1 x 10^-2

Solution:
Add the molar mass:
Al: 26.982 x 1 = 26.982
N: 14.007 x 3 = 42.021
O: 16.000 x 9 = 144
MW = 213.003

CONVERT mL to L

1575 -> 1.575

20.54/213.003 = 0.0964
0.0964/1.575

= 0.0612

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16
Q

What is the Molarity of 2 moles of NaOH in a 100 mL solution?

A

20

Solution
CONVERT mL to L

100mL -> 0.1L

REMEMBER: M = Moles/L of solution

2/0.1 = 20

17
Q

Normality is _________ or equal to molarity base on the __________

A

Greater than, Valence

18
Q

If the valence is greater than 2, the Normality is __________ Molarity

A

Greater than

19
Q

If the valence is 1, the Normality is __________ Molarity

A

equal to molarity

20
Q

If Normality is given and you need to find Molarity, what is the formula?

a. N/V
b. N x V

21
Q

If Molarity is given and you need to find Normality, what is the formula?

a. M/V
b. M x V

22
Q

What is the Normality of 0.1381 M NaOH?

A

0.1381 Eq/L

Solution:

Remember that the valence is the number of hydrogen

H = 1

Since molarity is Given the formula will be:

N = M X V

This indicates that If the valence is 1, the Normality is EQUAL TO Molarity

23
Q

What is the Normality of 0.0521 M H3PO4

A

0.156 N

Solution:

Valence: 3

N : M x V
N : 0.0521 x 3 = 0.156 N

24
Q

What is the normality of 24.5 g H2SO4 in a 100mL of solution? Molarity?
H = 1
S = 32
O = 16

A

N = 5 Eq/L
M = 2.5 M

Solution:

Add the Molar Mass:
H = 1 x 2 = 2
S = 32 x 1 = 32
O = 16 x 4 = 64
MW = 98

Valence = 2

EW = MW/V
EW = 98/2
EW = 49

CONVERT mL to L
100mL -> 0.1L
g/L = 24.5 g / 0.1L
g/L = 245 g/L

N = (245 g/L) / 49
N = 5

M = N/V
M = 5/2
M = 2.5

25
What is the Molarity in a 9.5 Eq/L H2O2?
M = 4.75 Solution: M = N/V M = 9.5 / 2 M = 4.75
26
How many mL of 60% ethanol are needed to prepare 2L of 20% ethanol? How much Distilled water is needed for to reach the total volume?
Volume for 60% ethanol: 666.67 mL Total volume: 1333.33 mL Solution: CONVERT L to mL 2L -> 2000mL V1 = (C2 x V2)/C1 V1 = (20 x 2000) / 60 V1 = 666.67 mL Total volume: 2000mL - 666.67 = 1333.33 mL
27
What is the concentration of a 2L or ethanol are needed to prepare 600mL of 20% ethanol?
6% Solution CONVERT mL to L or Vice versa 600mL to 0.6 L 2L to 2000mL C1 = (C2 x V2)/V1 C1 = (20 x 0.6) / 2 C1 = 6%
28
How much H2O2 is needed to prepare 10mL of a 1:10 dilution? What is Diluent volume?
Solute: 1 mL Diluent: 9mL Solution: Cross multiply: (X/10mL) x (1/10) = 10/10 = 1 mL Total volume is 10 from 1:10 Diluent volume: 10mL - 1mL = 9mL
29
A mixture consists of 2 parts of Solution A and 8 parts of Solution B. How many mL of Solution A and B are needed to create 5000 mL of the mixture?
Sol A = 1000 Sol B = 4000 Solution: Total volume of Solution: 2+8 = 10 Sol A: 2/10 = 0.2 0.2 x 5000mL = 1000mL Sol B: 5000mL - 1000mL = 4000mL
30
If 3mL of serum is mixed with 0.007L of saline determine the following: Dilution: Ratio of D to TV: Ratio of S to D: Ratio of TV to S:
Dilution: 3/10 (3:10) Ratio of D (Diluent) to TV: 7/10 (7:10) Ratio of Sample to Diluent: 3/7 (3:7) Ratio of TV to Sample:10/3 (10:3) Solution CONVERT L to mL 0.007 = 7mL Total volume: 3 + 7 = 10mL