The second option only.
<h3>Explanation</h3>
A base neutralizes an acid when the two reacts to produce water and a salt.
Sulfuric acid H₂SO₄ is the acid here. There are more than one classes of bases that can neutralize H₂SO₄. Among the options, there are:
Metal hydroxides
Metal hydroxides react with sulfuric acid to produce water and the sulfate salt of the metal.
.
The formula for calcium sulfate 
in option A is spelled incorrectly. Why? The charge on each calcium 
is +2. The charge on each sulfate ion 
is -2. Unlike 
ions, it takes only one ion to balance the charge on each ion. As a result, and ions in calcium sulfate exist on a 1:1 ratio.
.
Ammonia, NH₃
Ammonia NH₃ can also act as a base and neutralize acids. NH₃ exists as NH₄OH in water:
.
The ion 
acts like a metal cation. Similarly to the metal hydroxides, NH₃ (or NH₄OH) neutralizes H₂SO₄ to produce water and a salt:
.
The formula of the salt (NH₄)₂SO₄ in the fourth option spelled the ammonium ion incorrectly.
As part of the salt (NH₄)₂SO₄, the ammonium ion NH₄⁺ is one of the products of this reaction and can't neutralize H₂SO₄ any further.
Oceans are the most common of course
Answer:
0.175mol
Explanation:
Mole of a substance can be calculated using the formula as follows:
number of moles (n) = mass (m) ÷ molar mass (MM)
According to this question, there are 4.2g of Magnesium (Mg).
Molar mass of Magnesium = 24g/mol, hence, the number of moles of 4.2g of Mg is as follows:
n = 4.2g ÷ 24g/mol
n = 0.175mol
Answer:
Some things that were wrong with Rutherford's model were that the orbiting electrons should give off energy and eventually spiral down into the nucleus, making the atom collapse. Bohr proposed his quantized shell model of the atom to explain how electrons can have stable orbits around the nucleus. To remedy the stability problem, Bohr modified the Rutherford model by requiring that the electrons move in orbits of fixed size and energy.
Explanation:
When you inhale, air passes through the nasal cavity. There, mucus and hairs clean the air from most foreign particles before entering the body. Then, the air passes from the nasal cavity to the pharynx. After the pharynx, it passes through the larynx reaching the trachea. After passing through the trachea, the air reaches the bronchi, and after the bronchi, the bronchioles that branch off the bronchi. From the bronchioles, the air reaches the alveoli that is when gas exchange happens. O2 enters and CO2 leaves.
