Mass of Mg (g): 0.2000 Mass of oxide (g): 0.3317 1. Determine the empirical formula of the oxide of magnesium. (Think carefully about the precision of each mass that you measured before you do this calculation. How many significant figures are justified for each mass?) 2. Write the correctly balanced chemical equation for the reaction of magnesium with molecular oxygen. 3. Write the correctly balanced chemical equation for the reaction of magnesium with molecular nitrogen. 4. Write the correctly balanced chemical equation for the reaction of magnesium nitride with water. 5. Write the correctly balanced chemical equation for the reaction of heating magnesium hydroxide

1. Empirical formula is MgO

2. 2Mg + O₂ --> 2MgO

3. 3Mg + N₂ ---> Mg₃N₂

4. Mg₃N₂ + 6H₂O > 3Mg(OH)₂ + 2NH₃

5. Mg(OH)₂ ---> MgO + H₂O

Explanation:

1. Empirical formula:

mass of magnesium oxide = 0.3327 g; mass of magnesium = 0.2000 g

mass of oxygen = 0.3317 g - 0.2000 g = 0.1317 g

molar mass of magnesium = 24, molar mass of oxygen = 16

molar ratio of magnesium to oxygen is then calculated;

magnesium = 0.2000/24 = 0.0083 : oxygen = 0.1317/16 = 0.0082

magnesium = 0.0083/0.0082 = 1 : oxygen = 0.0082/0.0082 = 1

molar ratio of magnesium to oxygen = 1 : 1

Therefore, empirical formula is MgO

2. The reaction of magnesium with molecular oxygen produces magnesium oxide as shown by the equation below:

2Mg + O₂ --> 2MgO

3. The reaction of magnesium with molecular nitrogen produces magnesium nitride as shown by the equation below:

3Mg + N₂ ---> Mg₃N₂

4. The reaction of magnesium nitride with water produces magnesium hydroxide and ammonia gas as shown by the equation below:

Mg₃N₂ + 6H₂O > 3Mg(OH)₂ + 2NH₃

5. The products of the reaction of heating magnesium hydroxide are magnesium oxide and water as shown by the equation below:

Mg(OH)₂ ---> MgO + H₂O

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).