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EleoNora [17]
3 years ago
14

PJ’s unknown solid 1) dissolves in hot ethanol, 2) is essentially insoluble in hexane, and 3) is insoluble in cold water, but sp

aringly soluble in warm water. Outline the recrystallization procedure you would suggest she use here.
Chemistry
1 answer:
Gnoma [55]3 years ago
5 0

Answer:

1. The solid is dissolved in the hot solvent (ethanol or water);

2. If the impurities are not dissolved, they are separated by filtration;

3. The solution is then cold, and the crystals of the solid are formed;

4. The solution is filtrated and the pure solid is obtained.

Explanation:

The recrystallization is a process to separate impurities from a solid. The solid with the impurities is dissolved in a hot solvent, and, is insoluble in the cold one. But the impurities must be soluble in the cold solvent, or insoluble in the hot one.

If the impurities are soluble in the cold solvent, then, the crystals of the analyte will be removed, and if they are insoluble in the hot solvent, then its crystal is removed first.

So let's assume that the solid is insoluble in hot ethanol, and soluble in hot water. Because its insoluble in hexane, the recrystallization is not possible with it. So the procedure would be:

1. The solid is dissolved in the hot solvent (ethanol or water);

2. If the impurities are not dissolved, they are separated by filtration;

3. The solution is then cold, and the crystals of the solid are formed;

4. The solution is filtrated and the pure solid is obtained.

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5 0
3 years ago
The half-life of sr-90 is 28 years. after 56 years of decay only 0. 40 g of a sample remains. what was the mass of the original
Svetradugi [14.3K]

Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.

<h3>What is half-life?</h3>

The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,

N(t) = N_{0} (\dfrac{1}{2})^{ \frac{t }{t 1/2}}

Given,

Quantity of the remaining substance N (t) = 0.40 gm

Initial radioactive substance quantity N_{0} =?

Time duration (t) = 56 years

Half-life = 28 years

Substituting values above:

\begin{aligned} 0.40 &= N_{0} (\dfrac{1}{2}) ^{{\frac{56}{28}}\\\\0.40 &= N_{0} (\dfrac{1}{2})^{2}\end{aligned}

= 1.6 gm

Therefore, option d. the initial mass of Sr is 1.6 gm.

Learn more about half-life here:

brainly.com/question/16145921

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7 0
2 years ago
Which elements have high densities, strength, and resistance to corrosion?
Advocard [28]

Answer:

transition elements

Explanation:

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Answer: They Have Waxy Leaves And Stems

Explanation:

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7 0
3 years ago
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saw5 [17]

Answer:

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Names: carbon-14, C-14, radiocarbon

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Symbol: 14C

Explanation:

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