We have that the work function of the metal
From the Question we are told that
UV radiation (λ = 162 nm)
Kinetic energy 
Generally the equation for Kinetic energy is mathematically given as
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Different amount of species in an area.
Atomic mass Ca = 40 a.m.u
1 mole Ca ----------- 40 g
2.5 mols Ca -------- ( mass Ca )
Mass Ca = 2.5 x 40 / 1
Mass Ca = 100 / 1
= 100 g of Ca
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Answer: If a substance has a boiling point of 
then it is true that it will also change from a gas to a liquid at 78 °C while the gas loses energy.
Explanation:
The temperature at which vapor pressure of a liquid substance becomes equal to the atmospheric pressure is called boiling point of substance.
At the boiling point, liquid phase and vapor phase remains in equilibrium.
This means that as liquid phase changes into vapor phase and also vapor phase changes into liquid phase at the boiling point.
Thus, we can conclude that if a substance has a boiling point of then it is true that it will also change from a gas to a liquid at 78 °C while the gas loses energy.
Answer:
Yes. The two elements can combine to form different compounds.
Explanation:
Two elements can combine at different ratios.
Consider CO and CO₂. Both are made from carbon and oxygen. However, C and O combine at a 1:1 ratio in CO but at a 1:2 ratio in CO₂. CO is a fuel; it burns in the air. CO₂ does not burn in the air; it is used to put out fires and is found in extinguishers. CO and CO₂ are two distinct compounds.
There are many ways for the elements to combine with each other. As a result, the first twenty elements on the periodic table alone can produce a large number of compounds.
