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Magnesium metal reacts with hydrochloric acid according to the following equation:...

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kasane | Student, College Freshman

Posted August 15, 2012 at 2:46 AM via web

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Magnesium metal reacts with hydrochloric acid according to the following equation: Mg(s) + 2HCl (aq) ---> MgCl2(aq) + H2. What volume of 0.0400 M HCl(aq) is required to react with 6.08 grams of Mg(s)?

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted August 15, 2012 at 5:19 AM (Answer #1)

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The equation of the chemical reaction between magnesium and hydrochloric acid is: Mg(s) + 2HCl (aq) ---> MgCl2 (aq) + H2

From the equation it is seen that 2 moles of hydrochloric acid are needed to react with one mole of magnesium.

The molar mass of magnesium is 24.30 g/mole. 6.08 g of magnesium is equivalent to 6.08/24.30 or approximately 0.25 moles. 0.25*2 = 0.5 mole of hydrochloric acid is required to react with the magnesium. As the concentration of hydrochloric acid is 0.04 M or 0.04 mole/liter, the volume of acid required is 2*0.25/0.04 = 12.5 liters.

The volume of 0.04 M hydrochloric acid required for the given reaction with 6.08 g of magnesium is 12.5 liters.

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chaobas | College Teacher

Posted August 15, 2012 at 4:32 AM (Answer #2)

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The balanced reaction is 

Mg(s) + 2HCl (aq) ---> MgCl2(aq) + H2

 

here we  can see that the molar artio berween Mg and HCl is 1:2. That is  1mole of Mg requries 2 mol of HCl.

 

Mole = mass/molar mass

Moles of Mg = 6.08g/(24.31 g/mol)  [molar mass of Mg is 24.31 g/mol]

Moles of Mg = 0.25 mol Mg

 

So moles of HCl requried would be

 

0.25 Mg * (2 Mol HCl/1 mol Mg)

0.50 mol HCl

 

we know that 

Moraity = moles/volume

volume = moles/molarity

 

Volume of HCl = 0.50 mol /0.0400 M = 12.5 L

 

So 12.5 Liter of 0.040M HCl is required.

 

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