When 12 g of methanol (CH3OH) was treated with excess oxidizing agent (MnO4-), 14 g of formic acid (HCOOH) was obtained. Using the following chemical equation, calculate the percent yield. (The reaction is much more complex than this; please ignore the fact that the charges do not balance.) 3CH3OH + 4MnO4- > 3HCOOH + 4MnO2
(a) 100%
(b) 92%
(c) 82%
(d) 70%
(e) 55%

(c) 82%

Explanation:

Using the chemical reaction:

3CH₃OH + 4MnO₄⁻ → 3HCOOH + 4MnO₂ + 4e⁻

3 moles of methanol produce 3 moles of formic acid (Reaction 1:1)

To find the percent yield we need to calculate theoretical yield of the reaction when 12g of methanol (Molar mass: 32.04g/mol) are reacting, thus:

12g ₓ (1mol / 32.04g) = 0.3745 moles of methanol are in 12g.

As 1 mole of methanol produce 1 mole of formic acid, assuming a 100% of yield in the reaction (Theoretical yield) moles produced of formic acid are 0.3745 moles.

Using molar mass of formic acid (46.03g/mol), mass of the acid in 0.3745moles are:

0.3745 moles ₓ (46.03g/mol) = 17.2g of formic acid are theoretical yield

Percent yield is calculated as:

(actual yield / Theoretical yield) × 100

As actual yield of the reaction is 14g. Theoretical yield is:

(14g / 17.2g) × 100 = 81.2% ≈ 82%

Right answer is:

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.