Answer is: mass od zinc is 392,28 g.
N(Zn) = 3,6·10²⁴.
n(Zn) = N(Zn) ÷ Na.
n(Zn) = 3,6·10²⁴ ÷ 6·10²³ 1/mol.
n(Zn) = 6 mol.
m(Zn) = n(Zn) · M(Zn).
m(Zn) = 6 mol · 65,38 g/mol.
m(Zn) = 392,28 g.
Na - Avogadro number.
n - amount of substance.
M - molar mass.
Answer:
= 72900 years
Explanation:
- The half-life is the time taken by a radioactive material to decay by half the original amount.
- The half-life of plutonium-239 is 24300 years which means it takes 24300 years to decay by half the original amount.
To calculate the time taken for a mass of 8 kg to decay to 1 kg we use;
New mass = Original mass x (1/2) ^n, where n is the number of half-lives
Therefore;
1 kg = 8 kg × (1/2)^n
1/8 = (1/2)^n
solving for n;
n =3
Therefore;
Time = 3 × 24300 years
= 72900 years
It will, therefore, take 72900 years for 8 kg of plutonium-239 to decay to 1 kg.
4.) True:
Since
P(E) = 1 - P(Ec)
P(E)+P(Ec)=1
If you think of it as the chances of you getting e or not getting e, then it's a 100% chance of either one happening.
<u>Answer:</u> Silver has 47 electrons, 47 protons and 43 neutrons. Barium has 56 electrons, 56 protons and 76 neutrons.
<u>Explanation:</u>
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons
Atomic number = 47
Mass number = 90
Atomic number = Number of protons = Number of electrons = 47
Number of neutrons = Mass number - Atomic number = 90 - 47 = 43
Hence, silver has 47 electrons, 47 protons and 43 neutrons.
Atomic number = 56
Mass number = 132
Atomic number = Number of protons = Number of electrons = 56
Number of neutrons = Mass number - Atomic number = 132 - 56 = 76
Hence, barium has 56 electrons, 56 protons and 76 neutrons.
