Adding carbon to iron to make steel does make it stronger and tougher, up to a point. Then it will get stronger but less tough (ie like cast iron). Carbonstrengthens iron by distorting its crystal latice. This distortion is similar in effect to work hardening.
increases iron’s conductivity.
Answer:
B) 12.9 grams.
Explanation:
How many moles of molecules in that 6.30 L of H₂?
The volume of one mole of an ideal gas at STP (0 °C, 1 atm) is 22.4 liters.
(The volume of that one mole of gas at STP will be 22.7 liters if STP is defined as 0 °C and 10⁵ Pa).
.
How many moles of Na will be needed?
The coefficient in front of Na in the equation is twice the coefficient in front of H₂. It takes two moles of Na to produce one mole of H₂.
.
What's the mass of that many Na atoms?
Refer to a modern periodic table. The molar mass of ₁₁Na is 22.990. The mass of one mole of Na atoms is 22.990 gram. The mass of 0.5625 moles of Na atoms will be
.
(2 sig. fig. as in the volume of the H₂ gas.)
here we have to explain the development of the atomic theory by the atomic emission spectrum.
The most important aid in determining the structure of an atom has been study of radiation emitted and absorbed by the elements. The glowing atoms of an element emit radiations.
These are called the atomic spectra. This study helped to understand the structure of the atoms.
To explain the atomic spectra the Bohr's model was introduced. The postulates of the Bohr's model explain the fine spectrum of the atom up to the particle nature of the electrons.
Later some modification on the Bohr's postulates was made to explain the wave nature of the electrons as well. But the atomic spectra is best be understood by the Bohr's atomic model which developed the atomic theory.
Thus the understanding of emission spectrum of atom to develop the atomic theory is explained.
Answer:

Explanation:
First write all numerators above the common denominator
4/5 - 1/2 - 1/2=
- 1/2
Subtract the numbers
- 1/2 =
-
Write all numerators above the least common denominator 10
-
=

Subtract the numbers and you got your answer :)