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2 years ago

Use the periodic table to determine the number of valence electrons in each of the following elements.

2 answers:

5 0

Answer:
Na= 1, Ar= 8, V= 5, F= 7

Explanation:
You can determine the number of valence electrons in an element by looking the the group/column # on the periodic table. Elements in the same family/ group are organized by columns (vertical). Elements in the same column have the same number of valence electrons (electrons of the outermost shell) and consequently similar properties.
Simply put, GROUP #= # VALENCE E-

There are exceptions to this, especially when determining the amount of valence electrons in elements that are in a compound or in transition metal elements. For transition metals (that have different oxidation states- different # of valence electrons for the same element) I’d just look it up

Nina [5.8K]2 years ago

3 0

Answer:

Na: 1

F: 7

V: 5

Ar: 8

C: 4

Explanation:

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2 years ago

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 14.4 g of carbon were burned in the presence of

Natasha2012 [34]

When carbon reacts with oxygen it forms CO2. This can depicted by the below equation.

C + O2→ CO2

It has been mentioned that when 14.4 g of C reacts with 53.9 g of O2, then 15.5 g of O2 remains unreacted. This indicates that Carbon is the limiting reagent and hence the amount of CO2 produced is based on the amount of Carbon burnt.

C + O2→ CO2

In the above equation , 1 mole of carbon reacts with 1 mole of O2 to produce 1 mole of CO2.

In this case 14.4 g of Carbon reacts with 53.9 of O2 to produce "x"g of CO2.

No of moles = mass of the substance÷molar mass of the substance

No of moles of carbon = 14.4 /12= 1.2 moles

No of moles of O2 = Mass of reacted O2/Molar mass of O2.

No of moles of O2 = (Total mass of O2 burned - Mass of unreacted O2)/32

No of moles of O2 = (53.9-15.5) ÷ 32 = 1.2 moles.

Hence as already discussed 1 mole of Carbon reacts with 1 mole of O2 to produce 1 mole of CO2. In this case 1.2 moles of carbon reacts with 1.2 moles of O2 to produce 1.2 moles of CO2.

Moles of carbon dioxide = Mass of CO2 produced /Molar mass of CO2

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2 years ago

The equations given in the problem introduction can be added together to give the following reaction: overall: N2O4→2NO2 However

Murljashka [212]

Answer:

Reverse the $2 NO_2 \longrightarrow 2 NO + O_2$ reaction

Explanation:

Reactions:

$2 NO_2 \longrightarrow 2 NO + O_2$

$N_2O_4 \longrightarrow 2 NO + O_2$

Overall:

$N_2O_4 \longrightarrow 2 NO_2$

As can be seen, in the overall reaction we have $N_2O_4$ in the reactants like in the second reaction and $NO_2$ in the products. The $NO_2$ is in the first reaction but as a reactant so we need to reverse that reaction:

$2 NO + O_2 \longrightarrow 2 NO_2$

$N_2O_4 \longrightarrow 2 NO + O_2$

Combining:

$N_2O_4 + 2 NO + O_2\longrightarrow 2 NO + O_2 + 2 NO_2$

$N_2O_4 \longrightarrow 2 NO_2$

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Answer:

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