Amount of toxicant in concentrate = Q X C (Q X 48%)

Amount of toxicant in formulation = A X S (55 gal X 1%)

The amount of toxicant is constant; therefore,

AXS

Q X C = A X S, or Q = -------- .

C

Substituting the known values for the letters, we can solve for

Q as follows:

55 gal X 0 .01

Q = ------------ = 1.146 gal concentrate

0.48

(c) To the 1.1 (1.146 rounded) gallons of 48% diazinon emulsifiable

concentrate, we must add 53.9 gallons of water to prepare the desired 55 gallons of 1%

emulsion.

(2) Problem #2. In preparing dusts by diluting concentrated powders with

inert talc, the procedure is identical, but we are dealing with weight instead of volume.

Thus, to determine the amount of 80% carbaryl powder required to prepare 10 pounds

of 5% dust.

(a)

C = 80% (.80)

A = 10 lb

S = 5% (.05)

AXS

10 X 0.05

(b)

Q = ---------- =

------------

= 0.625 lb (10 oz)

C

0.80

(c) To the 10 ounces of 80% carbaryl powder, we must add 9

pounds, 6 ounces of inert talc or other carrier to prepare the desired 10 pounds of 5%

dust.

a. ** General. **From time to time the pest control operator will be required to

prepare suspensions, by mixing wettable powders with water. Because a given volume

of powder is considerably lighter than an equal of liquid, calculation by the

volume/volume method is not accurate. Therefore, we use the weight/weight

calculation, converting the volume of liquid to weight so that both values are expressed

in units of weight. A weight/volume calculation, then, is a calculation using a constant or

MD0173

2-9

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