Moles of Mg(OH)2, HNO3, Mg(NO3)2 in Reaction

[MellowOne]

Homework Statement

A sample of 5.53g of Mg(OH)2 is added to 25.0mL of 0.200M HNO3. How many moles of Mg(OH)2, HNO3, and Mg(NO3)2 are present after the reaction is complete?

Homework Equations

M = mol/L

The Attempt at a Solution

The balanced equation for the reaction is Mg(OH)2 + 2HNO3 -> Mg(NO3)2 + 2H2O

The limiter in this case would be HNO3 and I found that in 0.025L of this solution there is 0.315g of HNO3.

What I'm not sure is how to find the moles of each after the reaction is complete. I assume it's with stoichiometry, but I'm not sure how to find the moles of each at the end. I know that there should be 0 moles of HNO3 because it's used up correct? As for the Mg(OH)2, am I suppose to subtract the grams of HNO3 from the 5.53g of Mg(OH)2?

 

[Borek]

I know that there should be 0 moles of HNO3 because it's used up correct?

That's right.

Convert Mg(OH)₂ to moles.

Look at the coefficients in the reaction equation.

How many moles of Mg(OH)₂ will react with HNO₃?

How many moles of MgCl₂ will be produced?

How many moles of Mg(OH)₂ will be left?

 

[Blueshift5]

I would first convert the given mass of Mg(OH)2 to moles by using its molar mass (58.33 g/mol). This gives us 0.095 moles of Mg(OH)2. Next, using the given volume and molarity of HNO3, we can calculate the initial moles of HNO3 (0.005 moles).

Since HNO3 is the limiting reagent, it will be completely consumed in the reaction. This means that there will be no HNO3 left after the reaction is complete.

To find the moles of Mg(NO3)2 produced, we can use the mole ratio from the balanced equation. For every 1 mole of Mg(OH)2, we get 1 mole of Mg(NO3)2. Therefore, the moles of Mg(NO3)2 produced will also be 0.095 moles.

Finally, to find the moles of H2O produced, we can use the same mole ratio as before. For every 1 mole of Mg(OH)2, we get 2 moles of H2O. This means that 0.095 moles of Mg(OH)2 will produce 0.190 moles of H2O.

In summary, after the reaction is complete, there will be 0 moles of HNO3, 0.095 moles of Mg(NO3)2, and 0.190 moles of H2O present. It is important to note that these are the theoretical values and in a real experiment, there may be slight variations due to experimental error.