Calculate the mole fraction of KI in a solution made by dissolving 3.4 g of KI in 5.8 g of water. (Step by step) A. 0.060
B. 0.064
C. 0.37
D. 0.59
E. 6.4

The correct answer is 0.058

Step-by-step explanation:

The mole fraction of KI (X) in the solution is the number of moles of KI divided into the total number of moles of the solution (nt):

X= moles KI/nt

First we have to calculate the molecular weights of the components of the solution: KI and water (H₂O):

Molecular weight (Mw) of KI:

Mw(KI)= 39 g/mol + 127 g/mol = 166 g/mol

Molecular weight of H₂O:

Mw(H₂O)= (1 g/mol x 2) + 16 g/mol = 18 g/mol

Then, we calculate the number of moles there is of each component in the solution by dividing the mass into Mw:

Moles of KI= mass KI/Mw(KI) = 3.4 g/166 g/mol = 0.020 mol KI

Moles of H₂O= mass H₂O/Mw(H₂O)= 5.8 g/18 g/mol = 0.322 mol H₂O

Thus, the total moles of solution will be:

nt= moles KI + moles H₂O= 0.020 mol + 0.322 mol = 0.342 mol

Finally, we divide the moles of KI into the total moles of solution (nt) to obtain the mole fraction (X):

X= moles KI/nt = 0.020 mol/0.342 mol = 0.058

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).