You have obtained a gas chromatogram of a two component mixture of compounds a and b. the height of peak a is 3.96 cm. and the width at half height is 1.25 cm. the height of peak b is 4 cm. and the width at half height is 1.17 cm. the percentage of a component in the mixture is proportional to peak area. estimate peak areas by multiplying height by width at half height. what was the percentage of compound b in the mixture? (enter your answer as a number without any percent symbol or the word percent.)

A: 51.4%

B: 48.6%

Explanation:

Hight A: 3.86 cm

Width at half height A: 1.25 cm

Area A: 3.86 cm x 1.25 cm = 4.95 cm²

Hight B: 4.00 cm

Width at half height B: 1.17 cm

Area B: 4.00 cm x 1.17 cm = 4.68 cm²

Total area = 4.95 + 4.68 = 9.63 cm²

Since the percentage of a component in the mixture is proportional to peak area, we can calculate:

Percentage of A = Area A / Total area

Percentage of A = 4.95 / 9.63

Percentage of A = 0.514

Percentage of A = 52.4 %

Percentage of B = Area B / Total area

Percentage of B = 4.68 / 9.63

Percentage of B = 0.486

Percentage of B = 48.6 %

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .

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).