Calculations Flashcards

1
Q

What type of verification method is used in the maintenance/calibration of pipets?

A

gravimetric method (verifies accuracy of the amount of water dispensed by the pipet - weight is equal to volume dispensed)

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2
Q

Name two methods to calibrate pipets?

A

gravimetric (weight of water is proportional to the volume dispensed) AND volumetric (dye pipetted into specific volume that is then verified by spectrophotometry)

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3
Q

What is considered room temperature?

A

20 - 24 Celsius

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4
Q

What is the temperature for a general laboratory refrigerator?

A

2 - 8 Celsius

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5
Q

What is the temperature for a blood bank refrigerator?

A

1 - 6 Celsius

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6
Q

What is the temperature for a general laboratory freezer?

A

greater than or equal to -18 Celsius

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7
Q

What is the temperature for a blood bank freezer?

A

greater than or equal to -65 Celsius

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8
Q

What is the general temperature of a laboratory heat block?

A

36 - 38 Celsius

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9
Q

What is included as part of maintenance for microscopes?

A

daily cleaning of the microscope

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10
Q

Name one use for phase contrast microscopy.

A

manual platelet counts

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11
Q

Name one use for dark field microscopy.

A

identification of spirochetes

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12
Q

Name one use for polarized microscopy.

A

identification of urine crystals

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13
Q

What is the size of the eyepiece or ocular of a microscope?

A

10x objective

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14
Q

What is the function of the condenser of a microscope?

A

the movable part used to focus light onto the specimen

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15
Q

What is the size of the high powered (non-oil) objective?

A

40x

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16
Q

What is the function of the stage on a microscope?

A

hold the slide in place

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17
Q

When do you use the fine adjustment knob on a microscope?

A

focus under high power

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18
Q

When would one use the course adjustment knob on a microscope?

A

focus under low power

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19
Q

How should one carry a microscope?

A

by the base and arm

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20
Q

What is the purpose of the iris diaphragm on a microscope?

A

used to regulate the light intensity and size of the cone of light that is projected upward toward the slide

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21
Q

What is the size of oil immersion objectives?

A

between 50x and 100x

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22
Q

Describe the five SI Units of measure.

A
  1. Meter 2. kilogram 3. second 4. kelvin 5. mole
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23
Q

What is the scientific notation for the SI prefix “milli”?

A

10^-3 (milli -3)

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24
Q

What is the scientific notation for the SI prefix “femto”?

A

10^-15 (femto -15)

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25
Q

What is the scientific notation for the SI prefix “micro”?

A

10^-6 (micro -6)

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26
Q

What is the scientific notation for the SI prefix “Deci”?

A

10^-1 (deci -1)

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27
Q

What is the scientific notation for the SI prefix “Centi”?

A

10^-2 (centi -2)

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28
Q

What is the scientific notation for the SI prefix “Nano”?

A

10^-9 (nano -9)

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29
Q

What is the scientific notation for the SI prefix “Pico”?

A

10^-12 (Pico -12)

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30
Q

What is one way to remember the SI Prefixes?

A

Deci -1, Centi -2, Milli -3, Micro -6, Nano -9, Pico -12, femto -15

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31
Q

What is the scientific notation for the SI prefix “Deka”?

A

10^1 (deka 1)

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32
Q

What is the scientific notation for the SI prefix “Hecto”?

A

10^2 (hector 2)

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33
Q

What is the scientific notation for the SI prefix “kilo”?

A

10^3 (kilo 3)

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34
Q

What is the scientific notation for the SI prefix “mega”?

A

10^6 (mega 6)

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35
Q

What is the scientific notation for the SI prefix “giga”?

A

10^9 (giga 9)

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36
Q

What is the temperature conversion for Celsius?

A

Celsius = 5/9 (Fahrenheit - 32)

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37
Q

What is the temperature conversion for Fahrenheit?

A

Fahrenheit = (9/5) Celsius = 32

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38
Q

What is the temperature conversion for Kelvin?

A

Kelvin = Celsius + 273

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39
Q

How many milliliters are in one liter?

A

10^3

40
Q

Convert 104 F to Celsius.

A

C = (5/9) (104-32) C = 5/9 (72) C = (0.555) (72) C = 40

41
Q

What is the decimal equivalent of 5/9?

A

0.555

42
Q

What is the decimal equivalent of 9/5?

A

1.8

43
Q

Convert 25 C to Fahrenheit.

A

F = (9/5)(25) + 32 F = (1.8)(25) + 32 F = 45 + 32 F = 77

44
Q

Convert 22 C to Fahrenheit.

A

F = (9/5)(22) +32 F = (1.8)(22) + 32 F = 39.6 + 32 F = 71.6

45
Q

Convert 98 F to Celsius.

A

C = (5/9) (98-32) C = (0.55) (66) C = 36.3

46
Q

What are the mathematical order of operation?

A

Multiplication/division before addition/subtraction.

47
Q

Define a ratio.

A

amount of one substance/amount of second substance

48
Q

What is the BUN/Creatinine ratio if: BUN is 37.5 mg/dL Creatinine is 2.5 mg/dL

A

37.5 / 2.5 = 375/25 = 15 15:1

49
Q

What is the Cholesterol/HDL ratio if: HDL is 60 mg/dL Cholesterol is 240 mg/dL

A

240/60 = 4 4:1

50
Q

Define a serial dilution.

A

stepwise dilution of a substance in a solution.

51
Q

Define a simple dilution.

A

Process of decreasing the concentration of a solute in solution.

52
Q

What are the two parts of a 1:2 dilution?

A

1 part stock to 1 parts diluent

53
Q

What are the two parts of a 1:5 dilution?

A

1 part stock to 4 parts diluent

54
Q

What are the two parts of a 1:10 dilution?

A

1 part stock to 9 parts diluent

55
Q

What are the two parts of a 1:1 dilution?

A

1 part stock and 1 part total

56
Q

What are the values in a two-fold dilution?

A

2, 4, 8, 16, 32, 64, 128, 256, 512

57
Q

What are the values in a five-fold dilution?

A

5, 25, 125, 625

58
Q

What are the values in a ten-fold dilution?

A

10, 100, 1000, 10000

59
Q

Describe an example of a 10-fold serial dilution of a 1 stock/ml starting concentration.

A

1 stock/ml starting concentration 1 ml stock + 9 ml diluent = 0.1 stock/ml (1/10) 1 ml of 0.1 stock/ml + 9 ml diluent = 0.01 stock/ml (1/100) 1 ml of 0.01 stock/ml + 9 ml diluent = 0.001 stock/ml (1/1,000)

60
Q

Name the four different ways that concentrations can be expressed?

A
  1. percent solution 2. molarity 3. normality 4. molality
61
Q

What is the SI unit for molality?

A

mol/kg

62
Q

Is molality still used in the US today?

A

no, NIST considers the term ‘molal’ and the unit symbol ‘m’ to be obsolete. The suggested use is mol/kg.

63
Q

How is molar concentration most commonly expressed?

A

in units of moles of solute per liter of solution

64
Q

What three equations are used to represent percent solutions?

A
  1. weight/weight (w/w) 2. weight/volume (w/v) 3. volume/volume (v/v)
65
Q

Perform calculations for the following example of weight/weight percent solutions: Make 100 g of a 5% solution of HCl

A

% mass of solute = mass solute / mass solution x 100 5% solute * 100 g solution / 100 = 5 g of HCl

66
Q

What is the formula for a weight/weight percent solution?

A

% by mass of solute (w/w%) = (mass solute/mass of solution) x 100

67
Q

What is the formula for a weight/volume percent solution?

A

concentration solute (w/v%) = (mass solute in g/volume of solution in mL) x 100

68
Q

What is the w/v% (percent solution) of NaCl is we dissolve 1.2g of NaCl in enough water to make a 160 ml saline solution?

A

w/v% = (1.2g/160ml) x 100 w/v% = 0.0075 x 100 w/v% = 0.75

69
Q

What is the formula for a volume/volume percent solution?

A

v/v% = (volume solute in ml / total volume of solution in ml) x 100

70
Q

What is the v/v% alcohol content of a wine with 12 ml of ethanol per 100 ml of solution?

A

v/v% = (12ml / 100ml) x 100 v/v% = 0.12 ml x 100 v/v% = 12

71
Q

What is the proof value of alcohol in regards to the volume/volume percent solution?

A

twice the v/v% value

72
Q

Using the w/v%: Make 1000ml of a 10% solution of NaOH

A

w/v% = (mass solute in g / volume of solution in ml) x 100 10 % = mass NaOH in g / 1000 ml x 100 (10x1000) / 100 = 100 g NaOH

73
Q

Using the v/v%: Make a 50 ml of a 2% solution of HCL

A

v/v% = (volume solute in ml / total volume solution in ml) x100 2% = (volume solute in ml / 50 ml) x 100 (2 x 50) / 100 = 1 ml of HCl

74
Q

What are the units of a w/v percent solution?

A

gram/ml

75
Q

What are the units of a w/w percent solution?

A

gram/gram

76
Q

What are the units of a v/v percent solution?

A

ml/ml

77
Q

What is the formula for molarity?

A

M = moles/Liter

78
Q

What is the equivalent to a gram molecular weight (GMW)?

A

1 mole = gram molecular weight

79
Q

What is the formula for Molarity if looking at mL?

A

M = mmoles/mL

80
Q

What is the formula for Molarity if looking at gram molecular weight?

A

M = gram molecular weight (1 mole) / Liter

81
Q

If a solution contains 40 grams of NaOH per liter, what is the molarity? gram molecular weight or molar mass of NaOH is 40 g/mol

A

M = 40 g/L x 1 mole/40g = 1 mole M = 1

82
Q

What is the atomic mass of sodium?

A

23

83
Q

What is the atomic mass of hydrogen?

A

1

84
Q

What is the atomic mass of oxygen?

A

16

85
Q

What is the atomic mass of potassium?

A

39

86
Q

How would you calculate the gram molecular weight of water?

A

Hydrogen (1) x 2 + oxygen (16) = 18 g/mol

87
Q

How would you calculate the gram molecular weight of NaOH?

A

sodium (23) + oxygen (16) + hydrogen (1) = 40 g/mol

88
Q

What is the SI unit for molar mass or gram molecular weight?

A

g/mol

89
Q

What is the valence of hydrochloric acid (HCl)?

A

1

90
Q

What is the valence of sodium hydroxide (NaOH)?

A

1

91
Q

What is the valence of sulfuric acid (H2SO4)?

A

2

92
Q

What is the valence of phosphoric acid (H3PO4)?

A

3

93
Q

What is the formula for calculating normality (N)?

A

N = equivalent (GMW/valence) / Liter

94
Q

What is valence?

A

the number of units that can be combined with hydrogen

95
Q

What is the formula for molality?

A

miliosmoles per kilogram (mOsmol/kg)

96
Q

Using the concentrated solutions formula: How many ml of 0.25N NaOH are needed to make 100 ml of a 0.05 N solution of NaOH?

A

C1 x V1 = C2 x V2 0.25 x V1 = 0.05 x 100 V1 = (0.05 x 100) / 0.25 V1 = 5 / 0.25 V1 = 20