Answer:
We could do two 1:50 dilutions and one 1:4 dilutions.
Explanation:
Hi there!
A solution that is 1000 ug/ ml (or 1000 mg / l) is 1000 ppm.
Knowing that 1 ppm = 1000 ppb, 100 ppb is 0.1 ppm.
Then, we have to dilute the stock solution (1000 ppm / 0.1 ppm) 10000 times.
We could do two 1:50 dilutions and one 1:4 dilutions (50 · 50 · 4 = 10000). Since the first dilution is 1:50, you will use the smallest quantity of the stock solution (if we use the 10.00 ml flask):
First step (1:50 dilution):
Take 0.2 ml of the stock solution using the third dispenser (20 - 200 ul), and pour it in the 10.00 ml flask. Fill with water to the mark (concentration : 1000 ppm / 50 = 20 ppm).
Step 2 (1:50 dilution):
Take 0.2 ml of the solution made in step 1 and pour it in another 10.00 ml flask. Fill with water to the mark. Concentration 20 ppm/ 50 = 0.4 ppm)
Step 3 (1:4 dilution):
Take 2.5 ml of the solution made in step 3 (using the first dispenser 1 - 5 ml) and pour it in a 10.00 ml flask. Fill with water to the mark. Concentration 0.4 ppm / 4 = 0.1 ppm = 100 ppb.
Answer:
b. mercury
Explanation:
Fishes and some other sea foods are are known to concentrate mercury in their bodies. Consumption of these products gradually accumulate mercury in the body over time.
More specifically, fishes like swordfish, king mackerel and shark are known to concentrate higher amount of mercury than other species of fishes. Hence, limiting their consumption will protect humans from mercury poisoning.
The correct option is b.
Answer:
18.22874999999973
I recommend you to round the nearest 1 d.p
Explanation:
<em>h</em><em>a</em><em>v</em><em>e</em><em> </em><em>a</em><em> </em><em>g</em><em>r</em><em>e</em><em>a</em><em>t</em><em> </em><em>d</em><em>a</em><em>y</em><em>!</em>
(ANS1)— P4 + 5O2 ---> 2P2O5
(ANS2)— C3H8 + 5O2---> 3CO2 + 4H20
(ANS3)— Ca2Si + 4Cl2 ---> 2CaCl2 + SiCl4
My guess is b for the question
