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.
Answer : The balanced equation is,

Explanation :
According to the Bronsted Lowry concept, Bronsted Lowry-acid is a substance that donates one or more hydrogen ion in a reaction and Bronsted Lowry-base is a substance that accepts one or more hydrogen ion in a reaction.
The balanced chemical reaction will be,

In this reaction, hydrofluoric acid is act as a Bronsted Lowry-acid because it donate one hydrogen ion to
and
is act as a Bronsted Lowry-base because it accept one hydrogen ion from
.
The questions tha science can answer are those can be tested to try to find a definite answer.
For example, whether light is wave or particle is matter of science.
Questions that cannot have a definite answer are the field of religion or philosophy, and are out of the boundaries of science.
For example, does a criminal deserve the punishment of not seeing light? It is a moral question, which to be responded needs the intervention of philosophy and that could have different anwers at different times and in different societies.
40.1g of nitrogen gas is produced.
The equation given is
2 NH₃ + 3 CuO →3 Cu + N₂ + 3 H₂O
This equation is already balanced.
When 3 moles of CuO are consumed, 1 mole of nitrogen gas is produced.
We get 1 mole of nitrogen from 3 moles of copper oxide.
We need to find the number of moles of nitrogen gas produced when 4.3 moles of copper oxide are consumed.
4.3/3 x 1 = 1.433 mols
- 1.433 mols of nitrogen gas are produced
- The molar mass of nitrogen gas is 14+14 = 28g
- The amount of nitrogen gas produced in grams is 28x1.433 = 40.1g
40.1g of nitrogen gas can be made when 4.3 moles of CuO are consumed.
Learn more about molarity here:
brainly.com/question/24305514
#SPJ10