How many milliliters of a 4.5 M HCl solution would be needed to react completely with 5.8 g of aluminum?
I know the answer is somewhere around 143 mL HCl, but I CANNOT figure out how to find that answer. I have done a conversion from g of Al to mL of HCl and I cannot find the real answer.
1. Write and balance the equation.
2Al + 6HCl ==> 2AlCl3 + 3H2
2. Convert 5.8 g Al to mols. mol = grams/atomic mass = 5.8/27 = approx 0.2 but you need a more accurate answer than that estimate.
3. Using the coefficients in the balanced equation, convert mols Al to mols HCl. That's 0.2 mol Al x (6 mols HCl/2 mols Al) = 0.2 x 6/2 = approx 0.6. Recalculate this one also.
4. Finally, M HCl = mols HCl/L HCl. You know M HCl and mols HCl, solve for L HCl and convert to mL.
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To find the amount of HCl needed to react with a given amount of aluminum, you can use stoichiometry, which is the relationship between the amounts of reactants and products in a balanced chemical equation.
First, let's write the balanced chemical equation for the reaction between aluminum (Al) and hydrochloric acid (HCl):
2Al + 6HCl → 2AlCl₃ + 3H₂
From the balanced equation, we can see that 2 moles of aluminum react with 6 moles of hydrochloric acid to form 2 moles of aluminum chloride and 3 moles of hydrogen gas.
To start, we need to convert the given mass of aluminum to moles. The molar mass of aluminum is approximately 27 g/mol.
Number of moles of aluminum = Mass of aluminum / Molar mass of aluminum
= 5.8 g / 27 g/mol
≈ 0.215 mol
Next, using the stoichiometric ratio, we can determine the number of moles of HCl required to react with the calculated moles of aluminum. From the balanced equation, we can see that 2 moles of aluminum react with 6 moles of HCl.
Number of moles of HCl = (Number of moles of aluminum) x (Moles of HCl / Moles of aluminum)
= 0.215 mol x (6 mol HCl / 2 mol Al)
= 0.645 mol HCl
Now we can find the volume of the HCl solution required, given its concentration of 4.5 M (moles per liter).
Volume of HCl solution (in liters) = Number of moles of HCl / Molarity of HCl
= 0.645 mol / 4.5 M
≈ 0.143 L
Finally, we need to convert liters to milliliters by multiplying by 1000:
Volume of HCl solution (in milliliters) = 0.143 L x 1000 mL/L
≈ 143 mL
Therefore, approximately 143 mL of the 4.5 M HCl solution would be needed to react completely with 5.8 g of aluminum.