Answer:
Explanation:
1. Atomic numbers:
Atomic number is the number of protons in an atom. It is one of the most diagonistic and representative number used in identifying an atom. The periodic table of element arranges elements based on this number.
No two elements have the same atomic number.
Protons are positively charged particles in an atom.
- In a neutral atom, the atomic number is the same as the number electrons since electrical neutrality is attained when the number of protons and electrons are the same.
- The atomic number determines the position of an atom on the periodic table and it is unique for every atom.
2.
Periodic patterns
These are trends on that can be predicted on the periodic table because they shew regularities down a group or sometimes across the period.
Some of these trends are atomic radius, electronegativity, metallicity, nuclear charge e.t.c
Properties of elements can be predicted using these patterns even before they are discovered.
b.
Physical property shared by Helium, Argon and Neon is that they are all gases. All group 8 elements are called noble or inert gases.
Chemical property of these elements: they are chemically unreactive.
These gases are very stable having complete electronic shell configuration. Every atom on the periodic table tries to attain the state of the noble gases.
C.
Noble Gases/ Inert Gases/ Group O elements
Root mean square velocity is the square root of the mean of the squares of speeds of different molecules. From kinetic theory of gas, the formula of root mean square velocity=C
= √
=√
=√
, where, R= Universal gas constant, T= Absolute temperature, P= Pressure, V= Volume of gas, d= Density of gas.
Given, T=273 K, P=1.00 x 10⁻² atm, d=1.24 x 10⁻⁵ g/cm³.
(a) Using the formula 
=√=√(3X1.00X10⁻²)/(1.24X10⁻⁵)=49.18
(b) Molar mass can be determined by using the formula =√{3RT}{M}
49.18=√
49.18²=√(3X8.314X273)/M
M=
M=1.67 ≅ 2
Molecular mass is 2.
(c) The gas is Helium (He) whose molecular mass is 2.
According to the balanced equation of the reaction:
2C2H2 + 5O2 → 4CO2 + 2H2O
So we can mention all as liters,
A) as we see that 2 liters of C2H2 react with 5 liters of oxygen to produce 4 liters of CO4 and 2 liters of H2O
So, when we have 75L of CO2
and when we have 2 L of C2H2 reacts and gives 4 L of CO2
2C2H2 → 4CO2
∴ The volume of C2H2 required is:
= 75L / 2
= 37.5 L
B) and, when we have 75 L of CO2
and 4CO2 → 2H2O
∴ the volume of H2O required is:
= 75 L /2
= 37.5 L
C) and from the balanced equation and by the same way:
when 5 liters O2 reacts to give 4 liters of CO2
and we have 75 L of CO2:
5 O2 → 4 CO2
?? ← 75 L
∴ the volume of O2 required is:
= 75 *(5/4)
= 93.75 L
D) about the using of the number of moles the answer is:
no, there is no need to find the number of moles as we called everything in the balanced equation by liters and use it as a liter unit to get the volume, without the need to get the number of moles.
As the air molecules move through the valve they have friction as they hit the walls, and its this friction that causes it to heat up.
Answer:
One AMU or 1 Atomic Mass Unit
