If you are needing at least 100. grams of HCI to be produced, how many
grams of SiCl4 is t needed? *
SiCl4(l)
+
_
H2O(l)
——
SiO2 (s)
+
HCl(aq)

116.4 g of SiCl4

Explanation:

SiCl4(l) +2H2O(l) > SiO2 (s) + 4HCl(aq)

Given this balanced reaction equation which will serve as a guide for our work, we can now look at the stoichiometry of the reaction.

Number of moles of HCl needed = mass of HCl/ molar mass of HCl

Molar mass of HCl= 36.46 g/mol

Number of moles of HCl= 100/36.46 g/mol= 2.74 moles

From the balanced reaction equation;

1 mole of SiCl4 yields 4 moles of HCl

x moles of SiCl4 will yield 2.74 moles of HCl

x= 2.74/4 = 0.685 moles of SiCl4

Therefore mass of SiCl4= number of moles of SiCl4 × molar mass of SiCl4

Mass of SiCl4= 0.685× 169.9 g/mol = 116.4 g of SiCl4

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).