To solve this problem, let us first calculate for the rate
constant k using the half life formula:
t1/2 = ln 2 / k
where t1/2 = half life period = 24,000 years, therefore k
is:
k = ln 2 / 24,000
k = 2.89 x 10^-5 / yr
Now we use the rate equation:
A = Ao e^(-k t)
where,
A = mass of Plutonium-239 after number of years
Ao = initial mass of Plutonium-239
t = number of years
A. t = 12,000 years, find A
A = 100g e^(- 2.89 x 10^-5 * 12,000)
A = 70.7 g
B. t = 24,000 years, find A
A = 100g e^(- 2.89 x 10^-5 * 24,000)
A = 50 g
C. t = 96,000 years, find A
A = 100g e^(- 2.89 x 10^-5 * 96,000)
<span>A = 6.24 g</span>
The difference between short period and long period is based upon the number of elements in each period. Shortest period is the first period which contains elements, while the longest period is the 6th period which contains 32 elements.
Answer:
A double displacement reaction or double replacement reaction.
Explanation:
Answer:
Tetrahedral, trigonal pyramidal, trigonal bipyramidal.
Explanation:
The VSPER theory states that the bonds of sharing electrons and the lone pairs of electrons will repulse as much as possible. So, by the repulsion, the molecule will have some shape.
In the ion PO₄³⁻, the central atom P has 5 electrons in its valence shell, so it needs 3 electrons to be stable. Oxygen has 6 electrons at the valence shell and needs 2 to be stable. 3 oxygens share 1 pair of electrons with P, and the two lone pair remaining in P is shared with the other O, then the central atom makes 4 bonds and has no lone pairs, the shape is tetrahedral.
In the ion H₃O⁺, the central atom O has 6 electrons in its valence shell and needs 2 electrons to be stable. The hydrogen has 1 electron, and need 1 more to be stable. The hydrogens share 1 pair of electrons with the oxygen, then it remains 3 electrons at the central atom, and the VSPER theory states that the shape will be a trigonal pyramidal.
In the AsF₅, the central atom As has 5 valence electrons, and F has 1 electron in its valence shell, so each F shares one pair of electrons with As, and there are no lone pairs in the central atom. For 5 bonds without lone pairs, the shape is trigonal bipyramidal.
