Calculations Flashcards by Wissam Hamou

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

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

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Name two methods to calibrate pipets?

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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What is considered room temperature?

20 - 24 Celsius

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What is the temperature for a general laboratory refrigerator?

2 - 8 Celsius

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What is the temperature for a blood bank refrigerator?

1 - 6 Celsius

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What is the temperature for a general laboratory freezer?

greater than or equal to -18 Celsius

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What is the temperature for a blood bank freezer?

greater than or equal to -65 Celsius

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What is the general temperature of a laboratory heat block?

36 - 38 Celsius

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What is included as part of maintenance for microscopes?

daily cleaning of the microscope

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Name one use for phase contrast microscopy.

manual platelet counts

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Name one use for dark field microscopy.

identification of spirochetes

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Name one use for polarized microscopy.

identification of urine crystals

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

10x objective

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What is the function of the condenser of a microscope?

the movable part used to focus light onto the specimen

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

40x

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What is the function of the stage on a microscope?

hold the slide in place

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

focus under high power

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

focus under low power

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How should one carry a microscope?

by the base and arm

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

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

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What is the size of oil immersion objectives?

between 50x and 100x

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Describe the five SI Units of measure.

Meter 2. kilogram 3. second 4. kelvin 5. mole

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

10^-3 (milli -3)

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

10^-15 (femto -15)

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What is the scientific notation for the SI prefix "micro"?

10^-6 (micro -6)

What is the scientific notation for the SI prefix "Deci"?

10^-1 (deci -1)

What is the scientific notation for the SI prefix "Centi"?

10^-2 (centi -2)

What is the scientific notation for the SI prefix "Nano"?

10^-9 (nano -9)

What is the scientific notation for the SI prefix "Pico"?

10^-12 (Pico -12)

What is one way to remember the SI Prefixes?

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

What is the scientific notation for the SI prefix "Deka"?

10^1 (deka 1)

What is the scientific notation for the SI prefix "Hecto"?

10^2 (hector 2)

What is the scientific notation for the SI prefix "kilo"?

10^3 (kilo 3)

What is the scientific notation for the SI prefix "mega"?

10^6 (mega 6)

What is the scientific notation for the SI prefix "giga"?

10^9 (giga 9)

What is the temperature conversion for Celsius?

Celsius = 5/9 (Fahrenheit - 32)

What is the temperature conversion for Fahrenheit?

Fahrenheit = (9/5) Celsius = 32

What is the temperature conversion for Kelvin?

Kelvin = Celsius + 273

How many milliliters are in one liter?

10^3

Convert 104 F to Celsius.

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

What is the decimal equivalent of 5/9?

0.555

What is the decimal equivalent of 9/5?

1.8

Convert 25 C to Fahrenheit.

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

Convert 22 C to Fahrenheit.

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

Convert 98 F to Celsius.

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

What are the mathematical order of operation?

Multiplication/division before addition/subtraction.

Define a ratio.

amount of one substance/amount of second substance

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

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

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

240/60 = 4 4:1

Define a serial dilution.

stepwise dilution of a substance in a solution.

Define a simple dilution.

Process of decreasing the concentration of a solute in solution.

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

1 part stock to 1 parts diluent

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

1 part stock to 4 parts diluent

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

1 part stock to 9 parts diluent

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

1 part stock and 1 part total

What are the values in a two-fold dilution?

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

What are the values in a five-fold dilution?

5, 25, 125, 625

What are the values in a ten-fold dilution?

10, 100, 1000, 10000

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

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)

Name the four different ways that concentrations can be expressed?

1. percent solution 2. molarity 3. normality 4. molality

What is the SI unit for molality?

mol/kg

Is molality still used in the US today?

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

How is molar concentration most commonly expressed?

in units of moles of solute per liter of solution

What three equations are used to represent percent solutions?

1. weight/weight (w/w) 2. weight/volume (w/v) 3. volume/volume (v/v)

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

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

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

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

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

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

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?

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

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

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

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

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

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

twice the v/v% value

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

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

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

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

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

gram/ml

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

gram/gram

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

ml/ml

What is the formula for molarity?

M = moles/Liter

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

1 mole = gram molecular weight

What is the formula for Molarity if looking at mL?

M = mmoles/mL

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

M = gram molecular weight (1 mole) / Liter

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

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

What is the atomic mass of sodium?

What is the atomic mass of hydrogen?

What is the atomic mass of oxygen?

What is the atomic mass of potassium?

How would you calculate the gram molecular weight of water?

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

How would you calculate the gram molecular weight of NaOH?

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

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

g/mol

What is the valence of hydrochloric acid (HCl)?

What is the valence of sodium hydroxide (NaOH)?

What is the valence of sulfuric acid (H2SO4)?

What is the valence of phosphoric acid (H3PO4)?

What is the formula for calculating normality (N)?

N = equivalent (GMW/valence) / Liter

What is valence?

the number of units that can be combined with hydrogen

What is the formula for molality?

miliosmoles per kilogram (mOsmol/kg)

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?

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