<u>Explanation:</u>
Unit is defined as the quantity that is used as a standard for measurement.
S.I. unit of mass of kilograms. Other units in which mass of a substance can be measured are grams, milligrams, etc...
All these units are inter convertible.
The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

The conversion factor used is:

I dont know but the options are:
burning natural gasdissolving salt in watercarving stone with hammer and chisel<span>bending steel by hand</span>
Answer:
54.9 kJ/mol
Explanation:
The relation between the activation energy (Ea) and the rate constant (k) is given by the Arrhenius equation.

where,
A is a collision factor
R is the ideal gas constant
T is the absolute temperature
Reaction B is one million times faster than reaction A at the same temperature. So
.
Then,

Answer: Option (b) is the correct answer.
Explanation:
Insulator are the substances which do not conduct electricity. It is known that metals are good conductors of electricity. Whereas non-metals do not conduct electricity.
Out of the given options, silver, and calcium is a metal that means they are good conductors of electricity and are not insulators.
On the other hand, silicon is a metalloid, that is, it shows properties of both metals and non-metals. Hence, it will also show conductivity.
Phosphorus is a non-metal and therefore, it does not conduct electricity. As a result, out f the given options it will act as the best insulator.