A gas is at a pressure of 12 atm, a volume of 23 L, and a temperature of 200 K. If the pressure is raised to 14 atm, and the temperature is increased to 300 K. What is the new volume of the gas? (Show your work, including formula used)

≅ 30 Liters (1 sig. fig. based on Temp values 200K & 200K)

Explanation:

P₁ = 12 atm      =>    P₂ = 14 atm   Increase P  =>  Decrease V  => (12atm/14atm)

V₁ = 23 Liters  =>    V₂ =   ?          

T₁ = 200 K       =>    T₂ = 300 K    Increase T  =>  Increase V  =>  (300K/200K)

V₂ = V₁(P₁/P₂)(T₂/T₁) = 23L(12atm/14atm)(300K/200K) = 29.57143 L (Calc. Ans.)

≅ 30 Liters (1 sig. fig. based on Temp values 200K & 200K)

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

"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."