Explanation:
A point of temperature at which both solid and liquid state of a substance remains in equilibrium without any change in temperature then this temperature is known as melting point.
For example, melting point of water is 
. So, at this temperature solid state of water and liquid state are present in equilibrium with each other.
Therefore, when a 100 g of given pure metal in solid state is heated at its exact melting point which is 
then some of the solid will change into liquid state but the temperature will remains the same.
The number of potassium atom that are in 0.25 moles potassium carbonate is calculated as follows
by use of Avogadro contant
1 mole= 6.02 x10^23 atoms
what about 0.25 moles,
by close multiplication
{0.250 moles x 6.02 x10^23} / 1 mole = 1.505 x10^23 atoms
49 neutrons in each nucleus.
<h3>Explanation</h3>
For each nucleus:
Mass number = Number of protons + Number of neutrons.
The atomic number of a nucleus is the same as its number of protons. The atomic number of the nucleus here is 31. There are 31 protons in each nucleus.
- Mass number = 80;
- Number of protons = Atomic number = 31;
- The number of neutrons is to be found.
Again,
Mass number = Number of protons + Number of neutrons.
80 = 31 + Number of neutrons.
Number of neutrons = 80 - 31 = 49.
Continental air masses are characterized by dry air near the surface while maritime air masses are moist .Polar air masses are characterized by cold air near the surface while tropical air masses are warm or hot. Arctic air masses are extremely cold.
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