Molarity = mol/liter
0.708M = 0.098mol/L
Rearrange to find L:
0.098mol/0.708M = .138L
For every liter there is 1000 mL:
.138L • 1000mL =138mL KOH
Answer: The correct answer is the option: B. An element with eight valence electrons is chemically unstable.
Explanation:
Hello! Let's solve this!
We will analyze each of the options:
A. The group number of the element provides a clue to the number of valence electrons: it is correct, since it provides the number of valence electrons.
B. An element with eight valence electrons is chemically unstable: this is not correct, since elements with eight electrons in the valence shell cannot react because they already have the last complete shell. Therefore, they are chemically stable.
C. The points must be placed one at a time on each side of the chemical symbol: it is correct, because that is the way to make the point diagram.
D. An atom is chemically stable if all the points are paired: this is correct since this verifies that the point diagram has been done well.
We conclude that the correct answer is the option: B. An element with eight valence electrons is chemically unstable.
Hope this helps..... Stay safe and have a Merry Christmas!!!!!!!!! :D
Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
Answer:
Mechanical weathering
A. does not change rock composition
C. abrasion
F. ice wedging
Chemical weathering
B. oxidabon
D. changes rock composition
E. acid rain
Explanation:
Answer:
8.194 Mev per nucleon
Explanation:
Mass of Barium = 135.905 amu
number of proton = 56, number of neutron = 80
Md = (Mp + Mn) - Mb Mp is the mass of proton, Mn is the mass of neutron, Mb is the mass of barium and Md is the mass defect
Mn = 1.00867 amu Mp = 1.00728 amu
Md = ( 56 ( 1.00728) + 80 ( 1.00867) = 137.1013 - 135.905 =1.1963 amu
Md = 1.1963 × 1 ÷ ( 6.02214 × 10 ²⁶ amu ) = 1.9865 × 10 ⁻²⁷ kg
Energy = mc² = 1.9865 × 10 ⁻²⁷ kg × (2.99792 × 10 ⁸ m/s)²
E= 1.78537 × 10⁻¹⁰ J
to convert to Mev
1.78537 × 10⁻¹⁰ × 6241457006000 = 1114.33 Mev
binding energy per nucleon = 1114.33 / 136 =8.194 Mev per nucleon
