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Flashcards in Lab - Determination of Moisture Deck (16)
1

Water that is chemically bonded as hydrate/water of crystallization
A. bound
B. adsorbed
C. free

A

2

Water that is physically bound as monolayer to surface of food constituents
A. bound
B. adsorbed
C. free

B

3

Water that is essentially a sep.constituent
A. bound
B. adsorbed
C. free

C

4

involves the weight lost from a food item/sample due to the evaporation of water at or near the boiling point in a thermostatically-controlled oven.

Drying or Oven Method

5

another name for Drying/Oven Method

Indirect Distillation Method

6

For foods sensitive to heat, what instrument can be used? (Drying Method)

vacuum dessicator

7

Vacuum dessicator may be used in the drying method. If it is used, what is the drying agent?

H2SO4

8

In Immiscible Solvent Distillation Method, which is not a necessary criterion for the solvent?
A. Higher boiling point
B. Lower specific gravity
C. Ability to homogenize the mixture

C

9

Chemical method for determining moisture is also known as __

Karl Fischer titration method

10

Karl Fischer titration method: basis?

non-stoichiometric reaction of water with iodine & sulfur dioxide in pyridine methanol solution

11

In the oven method, how is the moisture calculated?

disparity of the weight before and after the drying

12

What solvent was used in the expt @ immiscible solvent distillaton method?

toluene

13

a. vapors condensed and trapped in calibrated tube
b. condensate collects as three layers
c. water in lower portion of condensate

Which does not happen in immiscible solvent distillation?

B

Two layers lang

14

in immisc. solvent distillation, how is percent moisture collected?

[ (vol of water in mL) / (wt of fresh sample) ] * 100%

15

In Oven Method, which is not a factor of weight loss?
A. Particle shape and aize
B. Weight of sample
C. Type of dish
D. Temp variations in oven

A

Particle size only

16

Karl Fischer method is often employed in foods with __ moisture
A. Low
B. Medium
C. High

A