Half life is the time taken by a radioactive isotope to decay by half its original mass.
The original mass is 200 g
Time taken is 60 hours
Final mass is 25 g
Therefore;
Final mass = Original mass × (1/2)^n; where n is the number of half lives.
25 = 200 (1/2)^n
1/8 = (1/2)^n
n = 3
Three half lives = 60 hours
1 half lives = 20 hours
Therefore; the half life of the radioactive nucleus is 20 hours
Answer:
There are 
Explanation:
In this problem, we need to find the number of molecules in 
mol of 
.
The molar mass of is 
No of moles = mass/molar mass
We can find mass from above formula.
Also,
No of moles = no of molecules/Avogadro number
Hence, there are
The nulear charge is the number of protons.
As the number of protons increases, the nuclear charge grows ant thhe pulling electrostatic force between them and electrons also grows, given that the electrostatic force is proportional to the magnitude of the charges.
As the number of electrons grows, they occupy outer shelss (farther from the nucleus). And the outer electrons will feel not only the atraction of the protons from the nucleus, but the repulsion of the inner electrons.
Then, we see that the increase of nuclear charge is opposed by the increase of core electrons, and the outer (valence) electrons are not so tied to the nucleus as the core electrons are.
This is called shielding effect. A way to quantify the shielding effect is through the effective nuclear charge which is the number of protons (Z) less the number of core electrons.
The more the number of core shells the greater the shielding effect experience by electros in the outermost shells.
The shielding effect, explains why the valence eletrons are more easily removed from the atom than core electrons, and also explains some trends of the periodic table: variationof the size of the atoms in a row, the greater the shielding efect, the less the atraction force felt by the outermos electron, the farther they are and the larger the atom.
Answer:
- 1 mole of carbon disulfide gas at 273 K and 40 L
- 1 mol of chlorine gas at 273 K and 40 L
- 1 mol of neon gas at 273 K and 40 L
- 1 mol of neon gas at 273 K and 20 L
- 1/2 mol of neon gas at 273 K and 20 L
- 1/2 mol of neon gas at 100 K and 20 L
- 1/2 mol of liquid neon at 100 K
Explanation:
Entropy is the measure of disorder or randomness in a closed system. Its an extensive property of a thermodynamic system
The following points must be considered when ranking the systems according to their entropy:
- The entropy of gases are highest than liquids or solid. And entropy of liquid is higher than solid. That is because gas has more microstate thus have the highest entropy.
- Entropies of large complicated molecules are greater than those of smaller, simpler molecules. Because larger molecules have more disorder because of the greater number of ways they can be move around in three dimensional space.
- highest temperature and highest volume will lead to greatest entropy
- 1 mole of any substance will have greater entropy than 1/2 mole of that same substance
An acid a. has a high pH in solution.
b. turns blue litmus paper to red.
c. releases hydroxyl ions in solution.
d. has more hydroxyl than hydrogen (or hydronium) ions.
<span>An acid </span>turns blue litmus paper to red. The answer is letter B.
