Greenhouse gases help regulate earths. A) oceans B) acid rain C) atmosphere D) temperature

Half life of the given radioactive substance after 1000 years  is 500 years.

What is half life?

Half -life of a substance  is defined as the time which is required  for half of the quantity of a radioactive substance to get decayed.It is a term which is used in nuclear chemistry for describing how quickly unstable atoms undergo radioactive decay into other nuclear species  by emitting particles or the time which is required  for number of disintegrations  per second  of radioactive material to decrease by one half of its initial value.

For the given problem, T=1000 years and N=25%  of N°

where  T=time period , N=amount of quantity after decay ,N°= initial quantity.

Here,N=25% of N°

N=25/100 N°=N°/4

N°/4=N°/2

n=2

∵nt=T

So. 2t=1000

t=500  years.

Hence, the half-life of a substance is 500 years.

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The mass in grams of one molecule of cholesterol, C27H46O is6.43×10⁻²² g

Avogadro's hypothesis

6.02×10²³ molecules = 1 mole of Cholesterol

But,

1 mole of Cholesterol = 387 g

Thus,

6.02×10²³ molecules = 387 g mole of Cholesterol

How to determine the mass of one molecule

6.02×10²³ molecules = 387 g mole of Cholesterol

1 molecule = 387 / 6.02×10²³

1 molecule = 6.43×10⁻²² g of Cholesterol

Thus, the mass of 1 molecule of cholesterol is 6.43×10⁻²² g

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The molar mass of cholesterol = 386.654 g/mol = 387 g/mole

3.2 mg cholesterol x 1 g/1000 mg x 1 mole/387 g x 6.02x1023 molecules/mole = 5.0x1018  molecules.

Answer:

To calculate the volume of the approximately 0.014 M copper (II) sulfate solution needed to prepare 100.00 milliliters of a 0.00028 M copper (II) sulfate solution, you can use the formula:

(Volume 1)(Concentration 1) = (Volume 2)(Concentration 2)

So, rearranging the formula, you can solve for Volume 1 (the volume of the 0.014 M solution):

Volume 1 = (Volume 2)(Concentration 2) / Concentration 1

Plugging in the values:

Volume 1 = (100.00 milliliters)(0.00028 M) / 0.014 M

Volume 1 ≈ 2.00 milliliters

Approximately 2.00 milliliters of the approximately 0.014 M copper (II) sulfate solution are needed to prepare 100.00 milliliters of a 0.00028 M copper (II) sulfate solution.