The average mass of an atom is calculated with the formula:
average mass = abundance of isotope (1) × mass of isotope (1) + abundance of isotope (2) × mass of isotope (2) + ... an so on
For the boron we have two isotopes, so the formula will become:
average mass of boron = abundance of isotope (1) × mass of isotope (1) + abundance of isotope (2) × mass of isotope (2)
We plug in the values:
10.81 = 0.1980 × 10.012938 + 0.8020 × mass of isotope (2)
10.81 = 1.98 + 0.8020 × mass of isotope (2)
10.81 - 1.98 = 0.8020 × mass of isotope (2)
8.83 = 0.8020 × mass of isotope (2)
mass of isotope (2) = 8.83 / 0.8020
mass of isotope (2) = 11.009975
mass of isotope (1) = 10.012938 (given by the question)
Answer:
Explanation:
In Polystrene, the molecular formula for the repeat unit = 
;
and the atomic weights of Carbon C = 12.01 g/mol
For Hydrogen, it is 1.01 g/mol
Hence, the repeat unit molecular weight is:
m = 8 (12.01 g/mol)+8(1.01 g/mol)
m = 96.08 g/mol + 8.08 g/mol
m = 104.16 g/mol
The degree of polymerization = no-average molecular weight/repeat unit molecular weight.
Mathematically;
Answer:
D. Nuclei with small masses combine to form nuclei with larger masses.
B. A small amount of mass in the nuclei that combine is converted to energy
Explanation:
A nuclear fusion, in contrary to fission, is the process by which the nuclei of two atoms combine to form a much larger atom with a large nuclei. Likewise, during a fusion reaction, a large amount of energy is released from the small amount of mass in the nuclei (two) that combines.
According to this question, the following are true of a fusion reaction:
- Nuclei with small masses combine to form nuclei with larger masses.
- A small amount of mass in the nuclei that combine is converted to enormous energy.
The formation of chemical bonds occurs due to the attractive forces between oppositely charged ions (ionic bonds) or by sharing of electrons (covalent bonds).
An atom having tendency of attracting a shared pair of electrons towards itself and this chemical property is said to Electronegativity .
Thus, the attractive forces which draws in surrounding electrons for chemical bonds is electronegativity.
First, since l = n-1,
5,4,-5,1/2 and 2,1,0,1/2 are the only answer choices left.
Next, since ml = -l to l,
2,1,0,1/2
is the answer because in 5,4,-5,1/2, the ml value of -5 is not in the range of -4 to 4, as notes by the value 4 for l.
