How many moles of H2 will be produced if 0.500g of Mg is reacted with 10.00mL of 2.0M HCl? Also, provide a balanced equation.
The balanced equation is
Mg+2HCl->H2+MgCl2 but I can't recall how to find the moles. Sorry, hope I helped a little!
This is a limiting reagent problem. I solve these by working TWO stoichiometry problems.
First, use moles Mg to solve for moles H2 formed. moles Mg = grams/molar mass.
Next, use moles HCl (moles = M x L) to solve for moles H2 formed. Both answers can't be right; the correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent producing that number is the limiting reagent. Here is an example of how to solve a stoichiometry problem.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the number of moles of H2 produced, we need to use stoichiometry based on the balanced equation for the reaction between magnesium (Mg) and hydrochloric acid (HCl). The balanced equation is:
Mg + 2HCl → MgCl2 + H2
From the equation, we can see that 1 mole of magnesium (Mg) reacts with 2 moles of hydrochloric acid (HCl) to produce 1 mole of hydrogen gas (H2).
Step 1: Calculate the number of moles of magnesium (Mg):
Given mass of Mg = 0.500g
The molar mass of Mg = 24.31 g/mol
Number of moles of Mg = mass / molar mass
Number of moles of Mg = 0.500g / 24.31 g/mol
Step 2: Calculate the moles of H2 produced using the mole ratio from the balanced equation:
Using the mole ratio from the balanced equation, 1 mole of Mg reacts with 1 mole of H2.
Number of moles of H2 = Number of moles of Mg
Step 3: Convert the volume of hydrochloric acid (HCl) to moles of HCl:
Given volume of HCl = 10.00 mL = 0.01000 L
Given concentration of HCl = 2.0 M (moles per liter)
Number of moles of HCl = volume × concentration
Number of moles of HCl = 0.01000 L × 2.0 M
Step 4: Determine the limiting reagent:
To determine the limiting reagent between Mg and HCl, compare the number of moles of each compound.
The limiting reagent is the one that is completely consumed first.
Step 5: Calculate the number of moles of H2 produced using the limiting reagent:
Based on the stoichiometry, the number of moles of H2 produced is equal to the number of moles of the limiting reagent.
Finally, add up the number of moles of H2 produced to get the total moles of H2.
Remember to keep track of significant figures throughout your calculations for accuracy.
Note: If the limiting reagent is HCl, the moles of HCl will dictate the moles of H2 produced. If the limiting reagent is Mg, the moles of Mg will dictate the moles of H2 produced.