<u>answer</u> 1<u> </u><u>:</u>
Law of conservation of momentum states that
For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
<u>answer</u><u> </u><u>2</u><u>:</u><u> </u>
When a substance is provided energy<u> </u>in the form of heat, it's temperature increases. The extent of temperature increase is determined by the heat capacity of the substance. The larger the heat capacity of a substance, the more energy is required to raise its temperature.
When a substance undergoes a FIRST ORDER phase change, its temperature remains constant as long as the phase change remains incomplete. When ice at -10 degrees C is heated, its temperature rises until it reaches 0 degrees C. At that temperature, it starts melting and solid water is converted to liquid water. During this time, all the heat energy provided to the system is USED UP in the process of converting solid to the liquid. Only when all the solid is converted, is the heat used to raise the temperature of the liquid.
This is what results in the flat part of the freezing/melting of condensation/boiling curve. In this flat region, the heat capacity of the substance is infinite. This is the famous "divergence" of the heat capacity during a first order phase transition.
There are certain phase transitions where the heat capacity does not become infinitely large, such as the process of a non-magnetic substance becoming a magnetic substance (when cooled below the so-called Curie temperature).
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.
What do you mean by this?
Good luck with your assignment :)
ANSWER: B salt does not evaporate with water