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Digiron [165]
3 years ago
15

Write about discovery of penicillin​

Chemistry
2 answers:
Rzqust [24]3 years ago
6 0

Answer:

The Scottish physician Alexander Fleming was the first to suggest that a Penicillium mould must secrete an antibacterial substance, and the first to concentrate the active substance involved, which he named penicillin, the first modern antibiotic, in 1928.

Sergio039 [100]3 years ago
4 0

Answer:

Penicillin was discovered in London in September of 1928. As the story goes, Dr. Alexander Fleming, the bacteriologist on duty at St. Mary’s Hospital, returned from a summer vacation in Scotland to find a messy lab bench and a good deal more.

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The boiling points of halogens increase in the following order F2 a. ion-dipole<br> b. hydrogen-bonding<br> c. ion-ion<br> d. di
Viefleur [7K]
In order for the molecule to change phase from liquid to gas and evaporates, it needs to overcome the force from other molecules around it. as the force bigger evaporation gets harder. so e has the highest force and higher boiling point.
8 0
3 years ago
A chemist prepares a solution of mercury(I) chloride Hg2Cl2 by measuring out
Genrish500 [490]

Answer:

1.26 × 10^-8 M

Explanation:

We are given;

Number of moles of mercury (i) chloride as 0.000126 μmol

Volume is 100 mL

We are required to calculate the concentration of the solution.

We need to know that;

Concentration is also known as molarity is given by;

Molarity = Number of moles ÷ Volume

Number of moles = 1.26 × 10^-10 Moles

Volume = 0.01 L

Therefore;

Concentration = 1.26 × 10^-10 Moles ÷ 0.01 L

                       = 1.26 × 10^-8 M

Thus, the molarity of the solution is 1.26 × 10^-8 M

6 0
3 years ago
The solubility of oxygen in lakes high in the Rocky Mountains is affected by the altitude. If the solubility of O2 from the air
IceJOKER [234]

Answer:

1.75\cdot 10^{-4} M

Explanation:

Henry's law states that the solubility of a gas is directly proportional to its partial pressure. The equation may be written as:

S = k_H p^o

Where k_H is Henry's law constant.

Our strategy will be to identify the Henry's law constant for oxygen given the initial conditions and then use it to find the solubility at different conditions.

Given initially:

S_1 = 2.67\cdot 10^{-4} M

Also, at sea level, we have an atmospheric pressure of:

p = 1.00 atm

Given mole fraction:

\chi_{O_2} = 0.209

According to Dalton's law of partial pressures, the partial pressure of oxygen is equal to the product of its mole fraction and the total pressure:

p^o = \chi_{O_2} p

Then the equation becomes:

S_1 = k_H \chi_{O_2} p

Solve for k_H:

k_H = \frac{S_1}{\chi_{O_2} p} = \frac{2.67\cdot 10^{-4} M}{0.209\cdot 1.00 atm} = 0.001278 M/atm

Now we're given that at an altitude of 12,000 ft, the atmospheric pressure is now:

p = 0.657 atm

Apply Henry's law using the constant we found:

S_2 = k_H \chi_{O_2} p = 0.001278 M/atm\cdot 0.209\cdot 0.657 atm = 1.75\cdot 10^{-4} M

8 0
3 years ago
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RSB [31]
The answer is the second choice.
5 0
2 years ago
Read 2 more answers
Why is pyridine included in the reaction of an acid chloride and an amine or alcohol? Pyridine will deprotonate the amine or alc
Pavel [41]

Answer:

Pyridine will neutralize the acid by-product of the reaction.

Explanation:

In the esterifications, hydrochloric acid is released as a by-product that reacts directly with the pyridine in the medium to give the pyridine hydrochloride.

7 0
3 years ago
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