Answer:
Here's what I get.
Explanation:
Mg + 2HCl ⟶ MgCl₂ + H₂
According to the Law of Conservation of Mass, the total mass of the products must equal the total mass of the reactants.
However, one of the products is a gas, hydrogen. The gas escapes into the atmosphere, so you will not be weighing it at the end of the reaction.
The mass of the test tube and contents after the reaction will be less than before the reaction.
However, that doesn't violate the Law of Conservation of Mass. You just didn't measure the mass of all the products.
Answer:
The balanced equation is:
2 HNO3 + Mg ---> Mg(NO3)2 + H2
From the equation, we can see that we need twice the moles of HNO3 than the moles of Mg
Moles of Mg:
Molar mass of Mg = 24 g/mol
Moles = Given mass / Molar Mass
Moles of Mg = 4.47 / 24 = 0.18 moles (approx)
Hence, 2(moles of Mg) = 0.36 moles of HNO3 will be consumed
Number of moles of HNO3 after the reaction is finished is the number of unreacted moles of HNO3
Unreacted moles of HNO3 = Total Moles - Moles consumed
Unreacted moles of HNO3 = 0.64 moles (approx)
Since we approximated the value of moles of Mg, the value of remaining moles of HNO3 will also be approximate
From the given options, we can see that 0.632 moles is the closest value to our answer
Therefore, 0.632 moles will remain after the reaction
The new volume : 0.07 L
<h3>
Further explanation</h3>
Boyle's Law
At a constant temperature, the gas volume is inversely proportional to the pressure applied
P₁=1 atm
V₁=0.39 L
P₂=5.6 atm
