Consider the following reaction. ch4 (g) + o2 (g) co2 (g) + h2o (l) a chemist allows 23.2g of ch4 and 78.3g o2 to react. when the reaction is finished, the chemist collects 52.7g co2. determine the limiting reagent, theoretical yield, and percent yield for the reaction

-

O 2 limiting reagent

53.83 g CO2 theoretical Yield

97.9% percentage yield

Explanation: -

Mas of CH4 = 23.2 g

Molar mass of CH4 = 12 x 1 + 1 x 4 = 16g

Mass of O2 = 78.3 g

Molar mass of O 2 – 16 x 2 = 32 g

The balanced chemical equation for the reaction is

CH4 + 2 O2 = CO2 + 2 H2O

From the balanced equation we see that

2 O 2 reacts with 1 CH4

2 x 32 g of O 2 react with 16 g of CH4

78.3 g of O 2 react with

= 19.575 g pf CH4

Thus CH4 is in excess.

The limiting reagent is thus O 2.

Molar mass of CO2 = 12 x 1 + 16 x 2= 12 +32 = 44g

From the balanced equation we see

2O 2 gives 1 CO2

2 x 32 g of O 2 gives 44g of CO2

78.3 g of O 2 gives =

=53.83 g of CO2

Theoritical Yield = 53.83 g of CO2

Actual yield = 52.7 g

Percentage yield =

=97.9 %

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."