Egg Substitute in Recipes

Last night I had my chicken soup happily bubbling on the stove, then went to the fridge to get eggs to begin making Danish Dumplings....woops, no eggs and no time to run to the store. NO, this was not the time to use an egg substitute but it got me thinking of what to do when I'm one egg short for a recipe. Powdered eggs are a favorite of mine which I do have on hand, but they are expensive to use all the time when its texture I'm looking for rather than flavor. I'm going to have to try these just for the fun of it, to see if I can taste or notice a difference!! Does this make me a chemist in some way? I hated chemistry, but real life experiments are easier to understand. The abstract concepts were always very hard for me, guess I'm a visual person needing pictures to help things make sense.

Egg Substitutes (Each recipe replaces one egg)

*It’s recommended not to replace more than 2 eggs per recipe.
1 tsp baking powder + 1 1/2 TBS water + 1 1/2 TBS oil
1 tsp baking powder + 1 TBS water + 1 TBS vinegar
2 TBS water or milk + 2 TBS flour + 1/2 TBS shortening + 1/2 tsp baking powder
1 TBS vinegar + 1 tsp baking soda
2 TBS lemon juice + 1 tsp baking soda
1 TBS cornstarch + 3 TBS water for each missing egg
2 TBS arrowroot flour
2 TBS potato starch
1 TBS tapioca starch + 1/4 cup warm water (mix well & allow to gel a bit before using)
1 tsp yeast dissolved in 1/4 cup warm water
1/2 banana, mashed (medium size) + 1/4 tsp baking powder
2 TBS applesauce
3 TBS mayonnaise