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3 years ago

If you start with 100 grams of a radionuclide, how much will you have after two half-lives have passed?

Chemistry

2 answers:

Contact [7]3 years ago

8 0

After first half-life you will have 100/2=50g. After second half-life you will have 50/2=25g.

zubka84 [21]3 years ago

6 0

25 grams.

A half life is the amount of time it takes for an isotope to decay half of itself.

So after one half life, there will be half of the original amount.

100/2=50

After another half life, there will be half of that amount.

50/2 = 25

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What is the purpose of doing a cell culture lab?

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Answer:

Cell culture is one of the most important techniques in cellular and molecular biology since it provides a platform to investigate the biology, biochemistry, physiology (e.g., aging) and metabolism of wild-type cells and diseased cells.

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3 years ago

The concentration of an HCl acid solution is initially 6mol/L. What would the concentration of a new solution be if 200 mL of th

pochemuha

Taking into account the definition of dilution, the concentration of the new solution is 1 mol/L.

<h3>Dilution</h3>

When it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.

Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

Ci: initial concentration
Vi: initial volume
Cf: final concentration
Vf: final volume

<h3>Final volume</h3>

In this case, you know:

Ci= 6 mol/L
Vi= 200 mL
Cf= ?
Vf= 1 L (1000 mL) water + 200 mL of HCL= 1200 mL

Replacing in the definition of dilution:

6 mol/L× 200 mL= Cf× 1200 mL

Solving:

(6 mol/L× 200 mL)÷ 1200 mL= Cf

In summary, the concentration of the new solution is 1 mol/L.

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2 years ago

A calorimeter contains 500 g of water at 25°C. You place a hand warmer containing 100 g of liquid sodium acetate (NaAC) inside t

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The heat absorbed by the water is
Q = 500 (4.18) (32.2 - 25)
Q = 15048 J

The enthalpy of fusion of the sodium acetate is:
<span>ΔHf = Q / m
</span><span>ΔHf = 15048 / 100
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3 years ago

Read 2 more answers

A chart that organizes elements by their chemical properties and increasing atomic number is the

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Periodic table!

The periodic table organizes elements by their chemical properties (mainly through vertical columns known as groups) and increasing atomic number.

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3 years ago

Methane gas and oxygen gas react to form water vapor and carbon dioxide gas. What volume of water would be produced by this reac

yanalaym [24]

volume of H₂O = 7.2 L

Explanation:

The combustion reaction of methane (CH₄):

CH₄ + 2 O₂ → CO₂ + 2 H₂O

Now we calculate the number of moles of methane using the following formula:

number of moles = volume / 22.4 (L/mole)

number of moles of CH₄ = 3.6 / 22.4

number of moles of CH₄ = 0.16 moles

Taking in account the chemical reaction, we devise the following reasoning:

if 1 mole of CH₄ produce 2 moles of H₂O

then 0.16 moles of CH₄ produce X moles of H₂O

X = (0.16 × 2) / 1 = 0.32 moles of H₂O

And now we can calculate the volume of water (H₂O) produced by the reaction:

number of moles = volume / 22.4 (L/mole)

volume = number of moles × 22.4 (L/mole)

volume of H₂O = 0.32 × 22.4

volume of H₂O = 7.2 L

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3 years ago