Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
Explanation:
so moles = mass ÷ mr (1+ 79.9)
so 10.00g ÷ 80.9
which is 0.1236093943
so to 3 S.F is 0.124 moles
also there is 1 to 1 ratio for LiOH to HBr
hope this helps :)
<span>rutherfordium element # 104</span>
Metal atoms have outer electrons which are not tied to any one atom. These electrons can move freely within the structure of a metal when an electric current is applied. There are no such free electrons in covalent or ionic solids, so electrons can't flow through them - they are non-conductors.
In a shorter term - no
Answer: X is a Solid; Y is a Gas
Explanation:
There are three (3) states of matter. They are: Solid, Liquid and Gases.
Substance X and Y, belong to the states of matter.
A Solid is a substance that retains its SIZE and SHAPE without need of a container (as opposed to a liquid or gas).
Thus, it will most likely be concluded that: substance X is a Solid; while Y is a Gas
