Consider the temperature versus time graph below. A graph of temperature versus time has time on the horizontal axis and temperature in degrees Celsius from negative 20 to 140 on the vertical axis. A line extends through the following points: 0, negative 10; 4, 0; 7, 140; 18, 120; 19, 125. At what temperature is the substance a heated gas? at 100°C below 0°C above 100°C between 0°C and 100°C

The answer is, C above 100 degrees Celsius

Explanation:

got it right in edg

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

a polar bond is formed when electrons are shared unevenly between atoms