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How many grams of mercuric chloride are needed to prepare 250ml of a 12% aqueous solution?
a) 4.8 b) 12 c) 30 d) 81 |
C) 30
In a 100ml solution of 12% mercuric chloride, 12 grams of mercuric chloride are needed, however 250ml is the final volume needed. Solve by substituting in the following: % required (or desired) : 100 = g or ml needed: final volume (or volume desired) or 12:100 = x:250 100x=3000 x=30 |
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What term best applies to a solution that contains all the dissolved solute possible at a given temperature?
a) dilute b) concentrated c) saturated d) supersaturated |
C) saturated
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To prepare 2 liters of 15% sodium chloride (MW NaCl = 58.5), the weighing of how many grams of NaCl would be required?
a) 30 b) 117 c) 150 d) 300 |
D) 300
This is a weight-volume relationship. In 100ml of 15% NaCl, 15g of NaCl are required; however 2 liters or 2,000ml is the final volume requested, so the proportion can be set up as follows: % required (or desired) : 100 = g or ml needed : final volume (or volume desired) 15g : 100ml = xg : 2000ml 15 x 2000 = 100 x = 300 |
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Molecules that behave either as acids or bases are called:
a) isometric b) hydrophobic c) amphoteric d) hydrophilic |
C) amphoteric
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Which of the following microscopes should be used to study unstained cell cytoplasm, nuclei, or inclusions?
a) light b) dark field c) phase contrast d) transmission electron |
C) phase contrast
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How many milliliters of water would be required to prepare 4500ml of 15% formalin?
a) 3825 b) 2812 c) 1688 d) 675 |
A) 3825
This is a volume-volume relationship. Stock formaldehyde contains 37-40% formaldehyde gas dissolved in water and is considered a 100% formalin solution. Dilution problems can be solved as follows: beginning% x beginning volume = desired % x desired volume C1V1=C2V2 100x = 15 x 4500 100x = 67500 x = 675ml formalin 4500 (total volume) - 675ml formalin = 3825ml water |
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When a substance is dissolved in water, the formation of charged particles is called:
a) ionization b) electrolyte c) colloid dispersion d) the Tyndall effect |
A) ionization
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A substance is considered an acid when it:
a) turns litmus paper blue b) is electrically neutral c) has a pH less than 7 d) accepts protons |
C) has a pH less than 7
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In the metric system, mass is expressed in:
a) pounds b) grams c) liters d) ounces |
B) grams
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1.652 grams is how many milligrams?
a) 16.52 b) 165.2 c) 1652 d) 16520 |
C) 1652
This may be solved as follow: desired units = given units times conversion factor. The conversion factor that converts grams to milligrams is 1000mg = 1g therefore, x = 1.652g x 1000, or 1652g |
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A substance is considered amphoteric when it:
a) has a pH of 5.0 b) can act as either an acid or a base c) changes the pH of a solution d) donates electron pairs to a base |
B) can act as either an acid or a base
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The recommended temperature of the oven used for drying paraffin sections should be adjusted to:
a) 10-20 degrees C b) 20-30 degrees C c) 50-60 degrees C d) 70-80 degrees C |
C) 50-60 degrees C
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The most effective knife for sectioning hard material is:
a) sintered tungsten carbide b) diamond c) steel d) glass |
B) diamond
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Sections for research are cut at 50 micrometers. The sections are how many millimeters in thickness?
a) 0.0005 b) 0.005 c) 0.05 d) 0.5 |
C) 0.05
1,000,000 micrometers equal 1 meter, and 1000 millimeters equal 1 meter, so this problem can be solved as follows: 50 : 1,000,000 = x : 1000 1,000,000x = 50000 x = 50,000 / 1,000,000 x = 0.05 |
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The two separate magnifying lens systems in the compound microscope are the:
a) condenser and objective b) objective and ocular c) ocular and object stage d) ocular and condenser |
B) objective and ocular
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