Magnesium: Chlorine and Hydrogen Moles
ATOMIC WEIGHT OF MAGNESIUM LAB
Introduction The main purpose of this experimental lab is to determine the atomic weight of magnesium, as well as an underlying purpose in determining the relationship between moles evolved and consumed. This can be demonstrated by measuring the hydrogen gas evolved by performing a chemical experiment when hydrochloric acid reacts with the magnesium.
The formulated reaction includes: Mg + 2HCl > H2 + Mg2+(aq) + 2Cl- (aq)
The major findings contributing to the experiment are being able to determine and distinguish what moles have evolved thus being the hydrogen moles evolved allowing the magnesium to be consumed within the reaction.
Procedure
Step 1: Obtain a 600 mL beaker, and add 300 mL of water.
Step 2: Add 30 mL of HCl (2M) to the beaker, and stir.
Step 3: Add 10 mg of magnesium metal to the beaker.
Step 4: Allow the hydrogen gas to evolve. All of the magnesium should be consumed.
Step 5: Record the amount of hydrogen gas that has evolved using the chemical property dialog.
Observations and Results Moles of hydrogen evolved: 0. 000411 (4. 11 x 10-4th) moles of H2 evolved.
The calculated atomic weight of magnesium: Weight of Mg /moles of H2 evolved [24. 305g/mol / 0. 000411 = 59,136. 25 g/mol of Mg] As I continued with my experiment I came across a few observations that are important to bring to attention. As I added 10 mg of magnesium to the beaker of HCl, a shaded area appeared at the bottom of the beaker. Directly after, bubbles formed in the same beaker thus indicating the Mg was being consumed.
Discussion
The moles of hydrogen gas that have evolved during the experiment resulted in 0. 000411. The calculated atomic weight of magnesium is determined by the formula of; atomic weight of Mg (in grams)=weight of Mg consumed (in grams) / moles of H2 evolved, therefore the equation should be similar to this; [24. 305g/mol / 0. 000411 = 59,136. 25 g/mol of Mg]. This experiment is clearly a branch of stoichiometry because a reaction takes place and it is the duty of the student to calculate or determine the relative atomic mass of Magnesium. The relationship between reactants and products.
