Parents SHOULDN'T avoid sharing their own mistakes with children.
Answer:
0.08 mL
Explanation:
The solution of the skin test has a concentration of 0.2% (w/v), which means that there are 0.2 g of the antigen per 100 mL of the solution. If a new solution will be done using it, then this solution will be diluted, and the mass of the antigen added must be the same in the volume taken and at the diluted solution.
The mass is the concentration (in g/mL) multiplied by the volume of the solution (in mL), so, if m is the mass, C the concentration, V the volume, 1 the initial solution, and 2 the diluted:
m1 = m2
C1*V1 = C2*V2
Where
C1 = 0.2 g/100 mL = 0.002 g/mL
V1 = ?
C2 = 0.04 mg/mL = 0.00004 g/mL
V2 = 4 mL
0.002*V1 = 0.00004*4
V1 = 0.08 mL
Answer:
Bacteria, fungi and nematodes
Answer:
The % yield is 56.6 %
Explanation:
This is the reaction:
C₂H₄ + Cl₂ → C₂H₄Cl₂
Molar mass of ethylene gas: 28 g/m
Mol = mass / molar mass
140 g / 28 g/m = 5 moles
Ratio is 1:1, so 5 moles of ethylene produce 5 moles of dichloro ethane.
Molar mass of C₂H₄Cl₂ = 98.9 g/m
Mass of C₂H₄Cl₂ produced = 98.9 g/m . 5 m → 494.5 g
% yield reaction
(280 g / 494.5 g ) . 100 = 56.6%
