Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
Answer:
C. Lose three electrons to have a full outer shell
Explanation:
Al is in Group 13 of the Periodic Table, so it has three valence electrons.
It must either lose three electrons or gain five to achieve a stable octet.
It is easier to lose three electrons than it is to gain five, so Al loses three electrons.
D. is wrong, for the same reason.
A. is wrong. If Al lost three electrons, it would be breaking into a stable inner shell.
C. is wrong. Al is a metal, so it will lose electrons in a reaction.
Answer:
False. They can be both omnivores and carnivores.
98 elements are naturally forming elements.
Answer: 98
Answer
B. acid + base --> salt + water
Explanation
Acids are substances that dissolve in water to produce hydrogen ions, H+.A base is a substance that dissolves in water to produce hydroxide ions, OH-.In a chemical reaction of an acid and a base, the products are a salt and water.For example when hydrocholoric acid is added to sodium hydroxide, a salt namely sodium chloride is formed with additional water.