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3 years ago

Why do you think there was a rush to mass-produce penicillin around the time of World War II?

Chemistry

2 answers:

Masja [62]3 years ago

6 0

Answer:

In 1940, Florey carried out vital experiments, showing that penicillin could protect mice against infection from deadly Streptococci.

Vladimir79 [104]3 years ago

5 0

Answer:

penicillin could protect mice against infection from deadly Streptococci.

Explanation:

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Do Alkali Metal Compounds form precipitates? And Why?

Alexeev081 [22]

Answer:

Alkali metal hydroxides can be used to test the identity of metals in certain salts. The colour of the precipitate will help identify the metal : Calcium hydroxide is soluble; no precipitate is formed.

6 0

3 years ago

What causes hot air to rise, and cool air to sink?

nataly862011 [7]

Answer:

hot air rises because gases expand as they heat up.When air heats up and expands,its density also increases.The warmer,less dense air effectively floats on top of the colder, dense air below it. This creates a buoyant force that causes warmer air to rise.

cold air sinks because it is heavier as its more dense ( because of closely packed molecules) soits harder for them to move and they absorb less energy. Also, gravity pulls on it more strongly.

Hope it helps :)

8 0

3 years ago

Identify the mixture of gasoline and motor oil and suggest a technique for separating their components. 1. homogeneous; decantin

alexgriva [62]

Answer:

4. homogeneous; distillation

Explanation:

Gasoline and motor oil are chemically similar. They are both mixtures of non polar hydrocarbons containing carbon and hydrogen atoms. However, motor oil is much more viscous Motor Oil. Hence we can say that the mixture of gasoline and motor oil are homogeneous and they can be separated by distillation.

4 0

4 years ago

Read 2 more answers

In the following chemical reaction between H_2 and Cl_2 to produce HCl, what is the mass of HCl produced and leftover reactants

ira [324]

Answer: The total amount of leftover reactants and HCl is 12.79 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For hydrogen gas:

Given mass of hydrogen gas = 0.36 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

$\text{Moles of hydrogen gas}=\frac{0.36g}{2g/mol}=0.18mol$

For chlorine gas:

Given mass of chlorine gas = 12.41 g

Molar mass of chlorine gas = 71 g/mol

Putting values in equation 1, we get:

$\text{Moles of chlorine gas}=\frac{12.41g}{71g/mol}=0.175mol$

The chemical equation for the reaction of hydrogen gas and chlorine gas is:

$H_2+Cl_2\rightarrow 2HCl$

By Stoichiometry of the reaction:

1 moles of chlorine gas reacts with 1 mole of hydrogen gas

So, 0.175 moles of chlorine gas will react with = $\frac{1}{1}\times 0.175=0.175mol$ of hydrogen gas

As, given amount of hydrogen gas is more than the required amount. So, it is considered as an excess reagent.

Thus, chlorine gas is considered as a limiting reagent because it limits the formation of product.

Moles of excess reactant left (hydrogen gas) = [0.18 - 0.175] = 0.005 moles

By Stoichiometry of the reaction

1 moles of chlorine gas produces 2 moles of HCl

So, 0.175 moles of chlorine gas will produce = $\frac{2}{1}\times 0.175=0.350$ moles of HCl

Now, calculating the mass of hydrogen gas left and HCl from equation 1, we get:

For hydrogen gas:

Molar mass of hydrogen gas = 2 g/mol

Moles of excess hydrogen gas = 0.005 moles

Putting values in equation 1, we get:

$0.005mol=\frac{\text{Mass of excess hydrogen gas}}{2g/mol}\\\\\text{Mass of excess hydrogen gas}=(0.005mol\times 2g/mol)=0.01g$

For HCl:

Molar mass of HCl = 36.5 g/mol

Moles of HCl = 0.350 moles

Putting values in equation 1, we get:

$0.350mol=\frac{\text{Mass of HCl}}{36.5g/mol}\\\\\text{Mass of HCl}=(0.350mol\times 36.5g/mol)=12.78g$

Total mass of HCl and leftover reactants = [12.78 + 0.01] = 12.79 g

Hence, the total amount of leftover reactants and HCl is 12.79 grams

7 0

4 years ago

Electronic configuration of 11N

joja [24]

Answer:

The Electronic configuration of 11N is

[Ne]3s1

3 0

3 years ago