If a 17.0 g sample of impure nickel metal reacts under standard conditions with 25.0 L of CO to form 6.25 L of Ni(CO)4 gas, what is the percentage of Ni in the metal sample?

Respuesta :

Answer:

96.33%

Explanation:

The equation of the reaction is represented as:

[tex]Ni_{(s)} + 4CO_{(g)}[/tex] ⇒ [tex]Ni(CO_{4})_{(g)}[/tex]

the molar mass of Ni = 58.7 g/mol

the molar mass of [tex]Ni(CO_{4})_{(g)}[/tex] = 171 g/mol

At Standard Temperature and Pressure;

25.0 L of CO = [tex]\frac{25.0}{22.4}[/tex]  =1.116mol

6.25 L of [tex]Ni(CO_{4})_{(g)}[/tex] = [tex]\frac{6.25}{22.41}[/tex] = 0.279mol

To calculate for the  percentage of Ni in the metal sample, we need to keep CO in excess, thereafter, we can say 0.279mol mol of Ni(s) equals to 0.279 mol of [tex]Ni(CO_{4})_{(g)}[/tex].

i.e

[tex]Ni(CO_{4})_{(g)}[/tex], in excess will require = [tex]\frac{1}{4}*1.116[/tex] = 0.279 mol of Ni(s).  

Given that, molar mass of Ni = 58.7 g/mol

and no of moles = [tex]\frac{mass}{molar mass}[/tex]

the mass can be calculated as = no of moles × molar mass

= 0.279  × 58.7

= 16.377 g Ni present in the sample

∴ the percentage of Ni in the metal sample = [tex]\frac{16.377}{17.0}*100%[/tex]

=96.33%

The percentage of Ni in the metal sample has been 96.33%.

The balanced equation for the reaction:

[tex]\rm Ni\;+\;4\;CO\;\rightarrow\;Ni(CO_4)[/tex]

At STP:

22.4 L gas = 1 mole

25 L carbon dioxide = 1.116 mol

6.25 L [tex]\rm Ni(CO_4)[/tex] = 0.279 mol.

1 mole [tex]\rm Ni(CO_4)[/tex] = 1 mole Ni

0.279 mol [tex]\rm Ni(CO_4)[/tex] =0.279 mol Ni.

Mass = moles × molecular weight

Mass of Ni = 0.279 [tex]\times[/tex] 58.7 g/mol

Mass of Ni = 16.377 g

The sample nickel = 17 grams.

Percentage of Nickel = [tex]\rm \dfrac{16.377}{17}\;\times\;100[/tex]

Percentage of Nickel = 96.33%.

The percentage of Ni in the metal sample has been 96.33%.

For more information about the percentage sample, refer to the link:

https://brainly.com/question/19637992

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