Half-life is a time in which the concentration of the substance gets reduced to 50% of the initial concentration. The number of tritium that will be left after 51 years is 0.624 kg.
<h3>What is an isotope?</h3>
Isotopes are chemical substances that have the same atomic number but different atomic mass because they have a different number of neutrons in the nuclei.
The half-life of the isotope, tritium is 12.3 years. Assuming we have 11 kg of substance and a number of years 51 years.

Therefore, the number of tritium that will be left after 51 years is 0.624 kg.
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A) 10.0g of Iron is

of Iron.
One mole of dihydrogen is required to form one mole of iron, hence you'll need

of dihydrogen.
B) Likewise : 2.50g of Iron is

of Iron, hence we'll need

of Fe2O3.
Two is wrong the rest are right
Answer:
Depending on where ozone resides, it can protect or harm life on Earth. Most ozone resides in the stratosphere (a layer of the atmosphere between 10 and 40 km above us), where it acts as a shield to protect Earth's surface from the sun's harmful ultraviolet radiation.
Explanation:
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