Answer:
6s
Explanation:
Barium is in group 2 of the s block and is in period 6.

<u>Difference </u><u>between </u><u>Atomic </u><u>mass</u><u>, </u><u>relative </u><u>atomic </u><u>mass </u><u>and </u><u>average </u><u>atomic </u><u>mass</u><u> </u><u>:</u><u>-</u>
<h3><u>Atomic </u><u>Mass </u><u>:</u><u>-</u></h3>
- Atomic mass is the mass of neutrons and protons present in the nucleus of an atom .
- It is always calculated for a single element and having direct value
- For isotopes also, the atomic mass is calculated separately . Example :- <u>Carbon </u><u>1</u><u>2</u><u> </u><u>,</u><u> </u><u>carbon </u><u>1</u><u>3</u><u> </u><u>and </u><u>carbon </u><u>1</u><u>4</u><u> </u><u>have </u><u>different </u><u>atomic </u><u>mass</u><u>. </u>
- The SI unit of Atomic mass is " u" and "amu"
<h3>
<u>Relative </u><u>Atomic </u><u>mass </u><u>:</u><u>-</u></h3>
- Relative atomic mass is mean mass of the atoms of an element which is compared to the 1/12th mass of carbon - 12 .
- Carbon - 12 is taken as a relative when we calculate the relative atomic mass of any element
- For calculating relative atomic mass, we need to know the masses, percentage and abundance of all types of elements
- Relative atomic mass is a dimension less quantity
<h3><u>Average </u><u>Atomic </u><u>Mass </u><u>:</u><u>-</u></h3>
- Average atomic mass is the average mass of an atoms of a particular element by considering it's isotopes
- While we calculate average atomic mass is a standardized number. Whereas, Average atomic mass sometimes varies geologically .
- It also includes percentage, abundance and masses of given element .
- In average atomic mass, We do not compare mean value with the 1/12 mass of carbon - 12
- The unit of Average atomic mass is "Amu" or " u " .
Answer:

Explanation:
Hello there!
In this case, according to the given combustion reaction of octane, it is possible for us to perform the stoichiometric method in order to calculate the mass of octane that is required to consume 300.0 g of oxygen by considering the 2:25 mole ratio, and the molar masses of 114.22 g/mol and 32.00 g/mol respectively:

Regards!
94.20 g/3.16722 mL = 29.74 g/mL
The ratio of mass to volume is equal to the substance's density. Thus, 29.74 g/mL is the density of whatever substance it may be. Density does not change for incompressible matter like solid and some liquids. Although, it may be temperature dependent.
the answer to your question is
M1V1=M2V2
V2=750-150=600 ml
0.75M*750 ml = M2*600
M2=0.75*750/600 ≈ 9.38 M