It will take 1.254 billion years to reach 29% of the original amount of U-235.
<h3>
First-order Radioactive Decay:</h3>
The rate constant can be calculated from the half-life. The relationship of the two is shown below:
× 
The first-order integrated rate law of a nuclide undergoing radioactive decay is;
ln[A]_t = -kt + ln[A]_0.
× 
×
It will take 1.254 billion years to reach to 29% of the original amount.
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Answer:
Explanation:
It is A. that is the only one that really makes any sense to me.
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The initial temperature is 137.34 °C.
<u>Explanation:</u>
As the specific heat formula says that the heat energy required is directly proportional to the mass and change in temperature of the system.
Q = mcΔT
So, here the mass m is given as 23 kg, the specific heat of steel is given as c = 490 J/kg°C and the initial temperature is required to find with the final temperature being 140 °C. Also the heat energy required is 30,000 J.
ΔT =
ΔT =
Since the difference in temperature is 2.66, then the initial temperature will be
Final temperature - Initial temperature = Change in temperature
140-Initial temperature = 2.66
Initial temperature = 140-2.66 = 137.34 °C
Thus, the initial temperature is 137.34 °C.
1) boiling points increase as molecular weight increase and vice versa. This is due to the increase in van der waals forces between molecules.
2) branching decreases the melting and boiling i.e increase in branching decrease boiling point and melting point. This is due to the fact that there are less point of contact between neighbouring molecules, so molecules are farther apart from each other, which means weaker van der waals(London forces) less energy is required to overcome these force of attraction.
3) In homolytic fission each of the fragment retain one of the bonded electron and radicals are made if the molecule is neutral. In heterolytic fission one fragment gets both bonding electron.
The energy for the heterolytic fission is higher because energy is not only needed to break the covalent bond but also to overcome the force of attraction between oppositely charged ions formed.
Answer:
pH = 8.1
Explanation:
Assuming that we are at 25 degrees Celsius, pH + pOH = 14.
We can then plug in the given pOH and solve for pH:
pH + pOH = 14
pH + 5.9 = 14
pH = 14 - 5.9 = 8.1
