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iogann1982 [59]
2 years ago
12

A sample contains 16. 75 g of the radioisotope U-236 and 50. 25 g of its daughter isotope, Th-232. How long did it take for deca

y to take place if one half-life of U-236 is 23 million years? 46 million years 69 million years 92 million years 115 million years.
Chemistry
2 answers:
garri49 [273]2 years ago
8 0

The time taken for the isotope to decay is 46 million years.

We'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:

  • Original amount (N₀) = 50.25 g
  • Amount remaining (N) = 16.75
  • Number of half-lives (n) =?

2ⁿ = N₀ / N

2ⁿ = N₀ / N

2ⁿ = 50.25 / 16.75

2ⁿ = 3

Take the log of both side

Log 2ⁿ = 3

nLog 2 = Log 3

Divide both side by log 2

n = Log 3 / Log 2

n = 2

Finally, we shall determine the time.

  • Half-life (t½) = 23 million years
  • Number of half-lives (n) = 2
  • Time (t) =?

t = n × t½

t = 2  × 23

t = 46 million years

Learn more about half-life: brainly.com/question/25927447

nekit [7.7K]2 years ago
3 0

Answer:

A.46 Million years

Explanation:

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The pressure in a car tire is 198 kPa at 27°C. After a long drive, the pressure
AlekseyPX

Answer : The temperature of the air in the tire is, 341 K

Explanation :

Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

P\propto T

or,

\frac{P_1}{T_1}=\frac{P_2}{T_2}

where,

P_1 = initial pressure = 198 kPa

P_2 = final pressure = 225 kPa

T_1 = initial temperature = 27^oC=273+27=300K

T_2 = final temperature = ?

Now put all the given values in the above equation, we get:

\frac{198kPa}{300K}=\frac{225kPa}{T_2}

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5 0
3 years ago
Given the balanced equation:
Aliun [14]

Answer:

0.4

Explanation:

Given data:

Number of moles of SrCl₂ consumed = ?

Mass of ZnCl₂ produced = 54 g

Solution:

Chemical equation:

ZnSO₄ + SrCl₂    →    SrSO₄ +  ZnCl₂

Number of moles of ZnCl₂:

Number of moles = mass/ molar mass

Number of moles = 54 g/136.3 g/mol

Number of moles = 0.4 mol

Now we will compare the moles of  ZnCl₂ with SrCl₂  from balance chemical equation.

                          ZnCl₂              :             SrCl₂

                              1                  :                1

                           0.4                 :              0.4

Thus when 54 g of  ZnCl₂ produced 0.4 moles of SrCl₂ react.

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Answer:

Explanation:

Two moles of magnesium (Mg) and five moles of oxygen (O2) are placed in a reaction vessel. When magnesium is ignited, it reacts with oxygen. What is the limiting reactant in this experiment?

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first, balance the equation

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two magnesium atoms react with one diatomic oxygen molecule

there is a 1:1 ratio of magnesium to oxygen atoms

but we have 2 moles of magnesium atoms and 2X5 = 10 moles of oxygen atoms

the lesser magnesium LIMITS the amount of product we can make, so it is the LIMITING REAGENT.

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