Answer:
2.1 x 10^24 Cr ions
Explanation:
You need to multiply the 3.5 mol by the Avogrado's number (6.022 x 10^23) to get your answer.
Answer:
One of the errors for low percentage of magnesium could be because not all the magnesium may have reacted.
Explanation:
During the heating process, if the magnesium have not reacted completely, it can lead to low percentage of magnesium in the oxide formed. The product may still look a bit greyish rather than whitish after the heating process.
Answer:


Explanation:
Hola.
En este caso, para calcular la longitud (a) de una cara de celda unitaria, consideramos la siguiente ecuación:

En la que consideramos el número de átomos por celda (4 para FCC), la masa molar (40.3 g/mol para MgO) y el número de avogadro para obtener:

Despejando para a, obtenemos:
![a^3 = \frac{4atom/celda*40.3g/mol}{3.581g/cm^3*6.02x10^{23}atom/mol}\\\\a=\sqrt[3]{7.478cm^3} \\\\a=4.213cm](https://tex.z-dn.net/?f=a%5E3%20%3D%20%5Cfrac%7B4atom%2Fcelda%2A40.3g%2Fmol%7D%7B3.581g%2Fcm%5E3%2A6.02x10%5E%7B23%7Datom%2Fmol%7D%5C%5C%5C%5Ca%3D%5Csqrt%5B3%5D%7B7.478cm%5E3%7D%20%5C%5C%5C%5Ca%3D4.213cm)
Finalmente, el radio lo calculamos como:

¡Saludos!
Energy is absorbed so, the mass is increased.
energy is released so, the mass is increased