The answer is 3.
Explanation:
It’s the last number and it can’t be 9 because then it would be 48.9 and no 3.
Physical changes are when things get changed without altering chemical consistencies, which is melting solid butter into liquid one, or boiling water. Chemical changes are things such as caramelizing sugar when making sweets, or when carbon dioxide is created and released when baking bread.
It benefits of the solar radiation for out planet is that it gives us heat, natural sunlight and its pollution free.The disadvantage for solar radiation is that there are also some toxic materials and hazardous products used during the manufacturing process of solar photovoltaic systems, which can indirectly affect the environment.
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For a gas containing 80% CH4 and 20% He is sent through a quart diffusion tube, the composition is mathematically given as
%He=12.5%
%CH4=87.5%
<h3>What is the
composition of the waste gas if 100 kg moles of gas are processed per minute?</h3>
Generally, the equation for the Material balance is mathematically given as
F=R+W
Therefore
100=0.20*1000+W
W=80kmol/min
In conclusion, waste gas compose
2.0/100*100=50/100*20+%*80
Hence
%He=12.5%
%CH4=87.5%
Read more about Chemical reaction
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<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.