Answer: 17.34 grams of alum will be produced if 0.9875 g of Aluminium foil was used.
Explanation: Reaction to form alum from Aluminium is given as:

We are given Aluminium to be the limiting reactant, so the formation of alum will be dependent on Aluminium because it limits the formation of product.
By stoichiometry,
2 moles of Al is producing 2 moles of Alum
Mass of 2 moles of Aluminium = (2 × 27)g/mol = 54 g/mol
Mass of 2 moles of alum = (2 × 474)g/mol = 948 g/mol
54 g/mol of aluminium will produce 948 g/mol of alum, so

Amount of Alum produced = 17.34 grams
Theoretical yield of alum = 17.34 grams.
Answer: Oxygen, Beryllium, Lithium, & Fluorine
Explanation:
theoretically it might not be the answer be
Answer:
C) low ionization energy and low electronegativity
Explanation:
Hypothesis: Sunlight is necessary for seedling growth.
Prediction: Seedlings grown in bags wrapped in aluminum-foil will be shorter than those in bags without aluminum-foil, because the aluminum keeps out sunlight.
A predection is somthing that you guess what it is like if you kick a ball you dont know where its going to go so you think or prdict where its going