So half life is the time taken for a sample to decay to half its original mass, its a constant and applies to any original mass, it could be 5g or 1kg, it will take the same amount of time for the original mass to half. In this case the half life is 3 days.
After 3 days the sample will be at half its original mass, now 50g.
Now we can treat the 50g as if its a new sample. After another 3 days (6 days in total) there will be half of 50g left, = 25g.
1.) A compound is a substance that originates from two or more separate elements. It shares some similarities with a mixture.
2.) A compound has quite different properties from which it was formed. It also cannot be separated easily. Compounds are formed by chemical reactions.
3.) A pure substance has a constant composition and has consistent properties. It can be a compound or an element, but its composition is constant.
Hope this helps. :)
Answer:
Explanation:
In a single-displacement reaction, one element exchanges partners with another element in a compound.
This is a single-displacement reaction, because the element Fe exchanges partners with H in HCl.
This is not a single-displacement reaction, because it is a reaction between two compounds.
This is a double displacement reaction in which the K⁺ and H⁺ cations change partners with the anions.
This is not a single-displacement reaction. It is another double displacement reaction, in which the Na⁺ and H⁺ cations change partners with the anions.
This is a single-displacement reaction, because the element Ca exchanges partners with H in H₂O.
are not single-displacement reactions.
