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3 years ago

18. How many moles of atoms are there in each of

Chemistry

1 answer:

Lelechka [254]3 years ago

3 0

a) 1 mole of Ne

b) i/2 mole of Mg

c) 1570 moles of Pb.

d) 2.18125*10^-13 moles of oxygen.

Explanation:

The number of moles calculated by Avogadro's number in 6.23*10^23 of Neon.

6.23*10^23= 1/ 6.23*10^23

= 1 mole

The number of moles calculated by Avogadro's number in 3.01*10^23 of Mg

3.2*10^23=1/6.23*10^23

= 1/2 moles of Pb.

Number of moles in 3.25*10^5 gm of lead.

atomic weight of Pb=

n=weight/atomic weight

= 3.25*10^5/ 207

= 1570 moles of Pb.

Number of moles 4.50 x 10-12 g O

number of moles= 4.50*10^-12/16

= 2.18125*10^-13 moles of oxygen.

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Answer: $4Fe+3O_2\rightarrow 2Fe_2O_3$

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Which of the following pairs lists a substance that can neutralize H2SO4 and the salt that would be produced from the reaction?

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The second option only.

LiOH, Li₂SO₄.

<h3>Explanation</h3>

A base neutralizes an acid when the two reacts to produce water and a salt.

Sulfuric acid H₂SO₄ is the acid here. There are more than one classes of bases that can neutralize H₂SO₄. Among the options, there are:

Metal hydroxides

Ca(OH)₂ and
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The formula for calcium sulfate $\text{CaSO}_4$ in option A is spelled incorrectly. Why? The charge on each calcium $\text{Ca}^{2+}$ is +2. The charge on each sulfate ion ${\text{SO}_4}^{2-}$ is -2. Unlike $\text{Li}^{+}$ ions, it takes only one $\text{Ca}^{2+}$ ion to balance the charge on each ${\text{SO}_4}^{2-}$ ion. As a result, $\text{Ca}^{2+}$ and ${\text{SO}_4}^{2-}$ ions in calcium sulfate exist on a 1:1 ratio.

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Ammonia, NH₃

Ammonia NH₃ can also act as a base and neutralize acids. NH₃ exists as NH₄OH in water:

$\text{NH}_3 + \text{H}_2\text{O} \to \textbf{NH}_{\bf 4}\text{OH}$ .

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The formula of the salt (NH₄)₂SO₄ in the fourth option spelled the ammonium ion incorrectly.

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