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2 years ago

Q. Calculate the number of atoms in each of the following (i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He

Chemistry

1 answer:

andreyandreev [35.5K]2 years ago

7 0

$\huge\mathfrak\red{❥︎AnSweR:-}$

(i) 1 mole of Ar =6.022×10^23

atoms of Ar

52 mol of Ar=52×6.022×10 ^23

atoms of Ar =3.131×10 ^25 atoms of Ar

(ii) Atomic mass of He = 4amu

4amu is the mass of He atoms = 1

Therefore 52 amu is the mass of He atoms=0.25×52=13 atoms of He

(iii) Gram atomic mass of He = 4g

4g of He contains =6.022×10 ^23

atoms

Therefore 52 g of He contains=

6.022×10 ^23/4×52 =7.83×10 ^24 atoms

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Thorium-234 has a half-life of 24.1 days. How many grams of a 150 g sample would you have after 120.5 days?

chubhunter [2.5K]

Answer:

8.625 grams of a 150 g sample of Thorium-234 would be left after 120.5 days

Explanation:

The nuclear half life represents the time taken for the initial amount of sample to reduce into half of its mass.

We have given that the half life of thorium-234 is 24.1 days. Then it takes 24.1 days for a Thorium-234 sample to reduced to half of its initial amount.

Initial amount of Thorium-234 available as per the question is 150 grams

So now we start with 150 grams of Thorium-234

$150 \times \frac{1}{2}=24.1$

$75 \times \frac{1}{2} =48.2$

$34.5 \times \frac{1}{2} =72.3$

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$8.625\times \frac{1}{2} =120.5$

So after 120.5 days the amount of sample that remains is 8.625g

In simpler way , we can use the below formula to find the sample left

$A=A_{0} \cdot \frac{1}{2^{n}}$

Where

$A_0$ is the initial sample amount

n = the number of half-lives that pass in a given period of time.

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3 years ago

1. How do metals and non-metals react with acids? Write and explain the chemical equation for the reaction of magnesium with sul

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Answer:

1. How do metals and non-metals react with acids?

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3 years ago

Read 2 more answers

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Answer : The Lewis-dot structure of $RbIO_2$ is shown below.

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, $RbIO_2$

As we know that rubidium has '1' valence electrons, iodine has '7' valence electrons and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $RbIO_2$ = 1 + 7 + 2(6) = 20

As we know that $RbIO_2$ is an ionic compound because it is formed by the transfer of electron takes place from metal to non-metal element.

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3 years ago

What is the Molar Mass of Cs2SO3?

Airida [17]

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Now add them all together.

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Hope that helps.

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3 years ago

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DanielleElmas [232]

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3 years ago

Q. Calculate the number of atoms in each of the following (i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He​

Q. Calculate the number of atoms in each of the following (i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He