Half life is the time taken by a radioactive isotope to decay by half its original mass. In this case, the halflife of the radioactive isotope is 5000 years.
Initially the mass is 100 %; thus the mass that will be left will be given by;
New mass = Original mass × (1/2)^n where n is the number of half lives;
n = 10000/5000 = 2
New mass = 100% ×(1/2)^2
= 100 % × 1/4
= 25%
Therefore; the mass left after 10000 years is 25% or 1/4 of the original mass.
B is your best answer because a mixture is when two or more things combine but not chemically. Take soup for example you take out all the pieces because they didn't combine together and just become 1 thing they still have parts. You can still take the noodles, you take the fish or meat out still, you take the broth away to.
I believe dimensional analysis
Answer: Reactivity is not a physical property, it is a chemical property.
Explanation:
Physical property is a value of matter that can be observed and measured without any change in composition of the matter. Examples of physical properties are color, combustion,melting point,boiling point,solubility, texture, appearance, polarity, odor,viscosity, density and many more.
Chemical properties are characteristics that are obvious or seen when substances undergo chemical reaction. Examples are reactivity,toxicity, acidity, flammability, and heat combustion.