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Kamila [148]
3 years ago
8

Why atomic mass is an average vàlue​

Chemistry
2 answers:
elena-s [515]3 years ago
7 0

Answer:

There are different isotopes for different elements

Explanation:

The mass of each of the isotopes of an element are added with their percentage each then they are divided by 100

Example boron 11 is 80 % boron 10 is 20%

Total mass of boron 10 is 20*10

Total mass of boron 11 is 80*11

Atomic mass is (20*10)+(80*11)/100

Which is 10.8 and it is rounded off as 11 in the periodic table

lukranit [14]3 years ago
4 0

Answer:

The atomic mass is the average number of protons and neutrons for all natural isotopes of an element. It is a decimal number.

Explanation:

Atomic Mass and Mass Number Example :

Hydrogen has three natural isotopes: 1H, 2H, and 3H. Each isotope has a different mass number.

1H has 1 proton. Its mass number is 1. 2H has 1 proton and 1 neutron. Its mass number is 2. 3H has 1 proton and 2 neutrons. Its mass number is 3. 99.98% of all hydrogen is 1H 0.018% of all hydrogen is 2H 0.002% of all hydrogen is 3H Together, they give a value of atomic mass of hydrogen equal to 1.0079 g/mol.

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salantis [7]

Answer:

Explanation:

When we react Hydrochlorid Acid with zinc we have the following reaction:

2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)

The hydrogen gas formed is lost to the environment, so we can affirme that in the start we have the mass for all the H, Cl and Zn atoms in the solution, but after the reaction occurs, we have only the mass for the Cl and Zn atoms.

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6 0
3 years ago
Read 2 more answers
How do you solve this ??
ICE Princess25 [194]

Answer:

Option D. 400 mmHg

Explanation:

The following data were obtained from the question:

Mole of He (nHe) = 0.04 mole

Mole of Ne (nNe) = 0.06 mole

Total pressure = 10³ mmHg

Partial pressure of He =.?

Next, we shall determine the total number of mole in the reaction vessel.

This can be obtained as follow:

Mole of He (nHe) = 0.04 mole

Mole of Ne (nNe) = 0.06 mole

Total mole =?

Total mole = nHe + nNe

Total mole = 0.04 + 0.06

Total mole = 0.1

Next, we shall determine the mole fraction of He.

This can be obtained as follow:

Mole fraction = mole of gas /total mole

Mole of He (nHe) = 0.04 mole

Total mole = 0.1

Mole fraction of He =.?

Mole fraction of He = nHe/total mole

Mole fraction of He = 0.04/0.1

Mole fraction of He = 0.4

Finally, we shall determine the partial pressure of He as follow:

Partial pressure = mole fraction x total pressure

Mole fraction of He = 0.4

Total pressure = 10³ mmHg

Partial pressure of He =.?

Partial pressure of He = 0.4 x 10³

Partial pressure of He = 400 mmHg.

Therefore, the partial pressure of He is 400 mmHg.

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Answer:

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