<span>Answer:
Some metals have the ability to form differently charged ions. For example, iron can form
2
+
or
3
+
ions. If you simply gave the name iron chloride, you would not know which charge the iron ion possessed.
A Roman numeral is to indicate the charge of the iron.
Iron (
II
) means the iron has a
2
+
charge
Iron (
III
) means that the iron has a
3
+
charge
So, iron (
II
) oxide would have a chemical formula of
FeO
.
(The oxide ion has a
2
â’
charge to balance the
2
+
of the iron to form a neutral compound.)
Iron (
III
) oxide would have a chemical formula of
Fe
2
O
3
(Here you need to find the common multiple of 6, so two iron ions with a
3
+
charge will balance the charge of three oxide ions with a
2
+
charge.)</span>
<span>The average speed of the gas is related to the kinetic
energy of the gas. The kinetic energy of
the gas is also related to the temperature of the gas. If the average speed of
the gas is closer to zero, it means that it has very low motion or kinetic
energy. This can be inferred that the gas has a very low temperature. At absolute
zero, the motion of all the gas molecules stops. This means that the kinetic
energy of the gas is also zero. Zero kinetic energy means zero average speed.</span>
<span>So, the answer is cylinder B. The average speed of the gas
in cylinder B is closest to zero.</span>
Yes, because the net ionic is equation will yield BaCO3 as a precipitate because it is insoluble in water
Answer:
The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is 
Explanation:
Given :
The energy E of the electron in a hydrogen atom can be calculated from the Bohr formula:
= Rydberg energy
n = principal quantum number of the orbital
Energy of 11th orbit = 
Energy of 10th orbit = 
Energy difference between both the levels will corresponds to the energy of the wavelength of the line which can be calculated by using Planck's equation.
(Planck's' equation)
The wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron for the given energy levels is
