Answer:
Two half lives.
Explanation:
It is known that the decay of isotopes and radioactive material obeys first order kinetics.
Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
That means for a sample 100% to decay to 50 % it will take one half-life, and to decay the remaining 50% to 25% it will take another half-life.
So, for a sample has 25% parent and 75% daughter it will have two half-lives.
Elements always exist as pair of atoms called molecules .
Explanation:-
- The material which has only one types of similar atoms called element .
- Ex:-Sodium,Carbon etc
Answer: 3.01 x 10^24 atoms
Explanation:
Based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms
So, 1 mole of SI = 6.02 x 10^23 atoms
5.0 moles = Z atoms
To get the value of Z, cross multiply:
(Z atoms x 1 mole) = (6.02 x 10^23 atoms x 5.0 moles)
Z atoms•1 mole = 30.1 x 10^23 atoms•moles
Divide both sides by 1 mole
Z atoms•1 mole / 1 mole = 30.1 x 10^23 atoms•moles / 1 mole
Z = 30.1 x 10^23 atoms
[Place Z in standard form
So, Z = 3.01 x 10^24 atoms]
Thus, there are 3.01 x 10^24 atoms in 5.0 moles in SI
Answer:
Explanation:
¡Hola!
En este caso, dado que estamos tratando con problem sobre porcentaje peso/peso de hierro, arena, cobre y aluminio, primero debemos calcular la masa inicial de estos dos primeros en la mezcla original de acuerdo con:
Ahora si podemos calcular la masa de la mezcla final como la suma de las masas de todos los constituyentes de la mezcla:
Finalmente, podemos calcular los porcentajes P/P como se muestra a continuación:
¡Saludos!
