Answer:
2.67 mL
Explanation:
The following data were obtained from the question:
Mass of tetracycline = 2 mg
Density of tetracycline = 0.75 mg/mL
Volume of tetracycline =?
We can obtain the volume of the tetracycline that should be given to the patient by applying the following equation:
Density = mass /volume
0.75 = 2 / volume
Cross multiply
0.75 × Volume = 2
Divide both side by 0.75
Volume = 2/0.75
Volume = 2.67 mL
Therefore, the volume of the tetracycline that should be given to the patient is 2.67 mL
Answer:
100ml of a stock 50% KNO3 solutions are needed to prepare 250ml of a 20% KNO3 solution.
Explanation:
In the given question it is mentioned that
S1=50%
V2=250ml
S2= 20%
We all know that
V1S1=V2S2
∴V1= V2×S2÷S1
∴V1= V2S2×1/S1
∴V1= 250×20÷50
∴V1= 100ml
The percentage of Chromium in Chromium Oxide is calculated as follow,
Step 1: Calculate Molar mass of Cr₂O₃,
Cr = 51.99 u
O = 16 u
So,
2(51.99) + 3(16) = 103.98 + 48 = 151.98 u
Step 2: Secondly divide molar mass of only chromium with total mass of Cr₂O₃ and multiply with 100.
i.e.
=

× 100
=
68.41 %
So, the %age composition of chromium in chromium oxide is
68.41 %.
Just ignore such kind of people....