In humans, having freckles is dominant over not having freckles. Andrew does not have freckles. What is his genotype for freckles? A) ff B) FF C) fF D) Ff

A)ff

Explanation:

its A bc, how you would write a dominate trait for having freckles is FF and how you would write a ressive(cant spell that word sorry) trait for having freckles is ff. if Andrew does not have freckles then he is a ressive, ff. and also my teacher told me that u always write a dominate trait before a ressive trait unless u r doing a tri hybrid cross or something else.

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

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