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.
2-11. WEIGHT/VOLUME CALCULATIONS
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