The mass of plutonium that will remain after 1000 years if the initial amount is 5 g when the half life of plutonium-239 (239pu, pu-239) is 24,100 years is 2.5 g
The equation is Mr=Mi(1/2)^n
where n is the number of half-lives
Mr is the mass remaining after n half lives
Mi is the initial mass of the sample
To find n, the number of half-lives, divide the total time 1000 by the time of the half-life(24,100)
n=1000/24100=0.0414
So Mr=5x(1/2)^1=2.5 g
The mass remaining is 2.5 g
- The half life is the time in which the concentration of a substance decreases to half of the initial value.
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3.16 X 10^-11 M is the [OH-] concentration when H3O+ = 1.40 *10^-4 M.
Explanation:
data given:
H30+= 1.40 X 10^-4 M\
Henderson Hasslebalch equation to calculate pH=
pH = -log10(H30+)
putting the values in the equation:
pH = -log 10(1.40 X 10^-4 M)
pH = 3.85
pH + pOH =14
pOH = 14 - 3.85
pOH = 10.15
The OH- concentration from the pOH by the equation:
pOH = -log10[OH-]
10.5= -log10[OH-]
[OH-] = 10^-10.5
[OH-] = 3.16 X 10^-11 is the concentration of OH ions when hydronium ion concentration is 1.40 *10^-4 M.
Answer:
There are often not more than one or two independent variables tested in an experiment.
The coefficients of the substances give you the ratio of the number of moles.
The 4 before the H2O and the 5 before the HCl tell you that for every 5 moles of HCl created, 4 moles of H2O had to react.
Therefore:
can be used to find the moles of H2O that react.
1) Atomic number of magnesium (Mg) is 12, it means that it has 12 protons and 12 electrons.
Electron configuration of magnesium atom: ₁₂Mg 1s² 2s² 2p⁶ 3s².
2) Atomic number of aluminium (Al) is 13, it means that it has 13 protons and 13 electrons., but if it lost one electron, it will have 12 electrons and 13 protons and become aluminium cation Al⁺.
Electron configuration of aluminium cation: ₁₃Al⁺ 1s² 2s² 2p⁶ 3s².
3) Atomic number of silicon (Si) is 14, it means that it has 14 protons and 14 electrons., but if it lost two electrons, it will have 12 electrons and 14 protons and become silicon cation Si²⁺.
Electron configuration of silicon cation: ₁₄Si²⁺ 1s² 2s² 2p⁶ 3s².
