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3 years ago

PLEASE HELP Determine the number of neutrons for the given isotopes:

Chemistry

2 answers:

Julli [10]3 years ago

4 0

Answer:

Helium: 1

Carbon: 2

Nitrogen: 8

Strontium: 52

Tellurium: 71

Explanation:

An isotope is a<em>tom that belongs to the same chemical element as another, has the same atomic number, but different atomic mass</em>

So the data they give us is the mass number of the isotopes

A= mass number

Z= atomic number ( number of protons in the nucleus).

IS the number that appears in the periodic table

For example, the Z of neon is 10 and the Z of the oxygen is 8

m= number of neutrons

A= Z+ m

m=A-Z

Helium:

$m=A-Z\\ m=3-2\\m=1$

Carbon:

$m=A-Z\\ m=14-12\\m=2$

Nitrogen:

$m=A-Z\\ m=15-7\\m=8$

Strontium:

$m=A-Z\\ m=90-38\\m=52$

Tellurium:

$m=A-Z\\ m=123-52\\m=71$

zepelin [54]3 years ago

3 0

<span>Helium = 1
Carbon = 8
Nitrogen = 8
Strontium = 52
Tellurium = 71

If you look on a periodic table, on each element there is a number on the top left. This represents the number of protons in an atom. Protons have a mass of 1 (in relative to Carbon-13)

If we take nitrogen-15 for example; The number 15 tells you that the isotope has a mass of 15. Now if you look on the periodic table, Nitrogen has a proton number of 7. Only protons and neutrons have a mass, electrons are considered to be negligable. Therefore the number of neutrons Nitrogen-15 contains is 15 - 7 = 8 </span>

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A flexible container at an initial volume of 6.13 L contains 6.51 mol of gas. More gas is then added to the container until it r

aivan3 [116]

Answer:

the final mole of the flexible container = 12.92 moles

Explanation:

Given that :

initial volume of a flexible container = 6.13 L

initial mole of a flexible container = 6.51 mol

final volume of a flexible container = 18.3 L

final mole of a flexible container = ???

Assuming the pressure and temperature of the gas remain constant, calculate the number of moles of gas added to the container.

Therefore,

$n= \dfrac{V_2*n_1}{V_1}$

$n= \dfrac{18.3*6.51}{6.13}$

n = 19.43

$n=n_1+n_2$

19.43 = 6.51 + n₂

n₂ = 19.43 - 6.51

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4 years ago

A student chromatographs a mixture and after developing the spots with a suitable reagent he observes the following

Anika [276]

Rf value is the ratio of the distance traveled by the solute to that of the solvent front on the paper used in chromatographic separation.

From the image it is clear the distance traveled by solvent front = 7.3 cm

Distance traveled by the component -1 of the mixture = 1.4 cm

Distance traveled by the component -2 of the mixture = 3.0 cm

Distance traveled by the component -3 of the mixture = 4.5 cm

Distance traveled by the component -4 of the mixture = 6.5 cm

Rf value of component-1 = $\frac{1.4 cm}{7.3 cm} =0.192$

Rf value of component-2 = $\frac{3.0 cm}{7.3 cm} =0.410$

Rf value of component-3 = $\frac{4.5 cm}{7.3 cm} =0.616$

Rf value of component-4 = $\frac{6.5 cm}{7.3 cm} =0.890$

b) Samples can be separated from a mixture using chromatography as the relative affinities for the compounds towards the paper (stationary phase) and the solvent(mobile phase) are different. Each component spends different amounts of time on the stationary phase depending on it chemical nature. So, the components in a mixture can be separated based on their polarities and relative degrees of adsorption on the stationary phase.

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When a sample of rust was mixed with acid, the rust changed into two simpler substances: W and Z. The substances W and Z could n

julia-pushkina [17]

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3 years ago

Read 2 more answers

Red mercury (II) oxide decomposes to form mercury metal and oxygen gas according to the following equation: 2HgO (s) 2Hg (l) + O

diamong [38]

hey there!:

2HgO (s) => 2Hg (l) + O2 (g)

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So 4.00 moles of HgO must give 4 moles of Hg and 2 moles of O2 theoretically.

603 g of Hg = 603 / 200.6 = 3 moles