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3 years ago

Which of these pairs of elements have the same number of valence electrons?

2 answers:

3 0

Both carbon and lead belong to Group IV elements, and thus they have the same number of valence electrons.
In each of the other options, the two elements belong to different groups, and thus they do NOT have the same number of valence electrons.

mars1129 [50]3 years ago

3 0

Answer:

IT IS B

Explanation:

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The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium azide, which produces

Oxana [17]

Answer:

1. NaN₃(s) → Na(s) + 1.5 N₂(g)

2. 79.3g

Explanation:

1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN₃) into solid sodium and gaseous dinitrogen.

NaN₃(s) → Na(s) + 1.5 N₂(g)

2. Suppose 43.0L of dinitrogen gas are produced by this reaction, at a temperature of 13.0°C and pressure of exactly 1atm. Calculate the mass of sodium azide that must have reacted. Round your answer to 3 significant digits.

First, we have to calculate the moles of N₂ from the ideal gas equation.

$P.V=n.R.T\\n=\frac{P.V}{R.T} =\frac{1atm.(43.0L)}{(0.08206atm.L/mol.K).286.2K} =1.83mol$

The moles of NaN₃ are:

$1.83molN_{2}.\frac{1molNaN_{3}}{1.5molN_{2}} =1.22molNaN_{3}$

The molar mass of NaN₃ is 65.01 g/mol. The mass of NaN₃ is:

$1.22mol.\frac{65.01g}{mol} =79.3g$

5 0

3 years ago

What is the electron configuration for 08 16

Elis [28]

The electron configuration for Oxygen : [He] 2s²2p⁴

<h3>Further explanation</h3>

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each sub-shell is

• s: 2 electrons

• p: 6 electrons

• d: 10 electrons and

• f: 14 electrons

Charging electrons in the sub-shell uses the following sequence:

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.

The element is Oxgen, with symbol O, and :

the atomic number=8=number of electron

the atomic mass=16

The electron configuration based on the number of electrons(for Oxygen=8), so the configuration :

$\tt _8^{16}O:1s^22s^22p^4$ or we can write with noble gas [He] 2s²2p⁴

3 0

2 years ago

Hello,

nikitadnepr [17]

Answer:

$a)\ 2FeSO4 \xrightarrow{\text{Heat}} SO_3+SO_2+Fe_2O_3\\b)\ Decomposition\ Reaction$

Explanation:

Ferrous Sulphate $(FeSO4)$ is generally found as Lime-Green Crystals. On heating, these crystals almost immediately turn white-yellow. They then, break down to produce an anhydrous mixture of Sulphur Trioxide $(SO_3)$ , Sulphur Dioxide $(SO_2)$ as well as Ferric Oxide $(Fe_2O_3)$ .

We can hence, frame a skeletal equation of this reaction and try to balance it.

Hence,

$FeSO4 \xrightarrow{\text{Heat}} SO_3+SO_2+Fe_2O_3$

Now,

a)In order to balance it through the 'Hit &Trial Method', we'll follow a series of steps:

1. First, lets compare the number of Fe (Iron) atoms on the RHS and LHS. We find that, the no. of Fe Atoms on the RHS is twice the number of Fe Atoms on the LHS. We hence, add a co-effecient 2 beside $FeSO_4$ .

2. Now, Iron atoms, Sulphur Atoms and Oxygen atoms occur 2, 2, 8 respectively on both the sides:

Hence, As all the other elements as well as iron, balance, we've arrived upon our Balanced Equation :

$2FeSO4 \xrightarrow{\text{Heat}} SO_3+SO_2+Fe_2O_3$

b) We know that, decomposition reactions are [generally] endothermic reactions in which Large Compounds decompose into smaller elements and compounds. Here, as Ferrous Sulphate decomposes into Sulphur Dioxide, Sulphur Trioxide and Ferric Oxide, the reaction that occurs here is Decomposition Reaction.

7 0

3 years ago

How many moles of Cl2 will produce 0.35 miles of NaCl when reacted with excess Na?

weeeeeb [17]

This question is based in mole ratios. for every mole of cl2, 2 moles of NaCl will be produced. so half of the moles of NaCl gives the moles of Cl2 required. therefore divide 0.35 by 2

6 0

3 years ago

1. An oxide of chromium is found to have the following % composition: 68.4% Cr

abruzzese [7]

Answer:

Empirical formula is Cr₂O₃.

Explanation:

Given data:

Percentage of Cr = 68.4%

Percentage of O = 31.6%

Empirical formula = ?

Solution:

Number of gram atoms of Cr = 68.4 / 52 = 1.3 2

Number of gram atoms of O = 31.6 / 16 = 1.98

Atomic ratio:

Cr : O

1.32/1.32 : 1.98/1.32

1 : 1.5

Cr : O = 1 : 1.5

Cr : O = 2(1 : 1.5)

Empirical formula is Cr₂O₃.

6 0

3 years ago