The answer would be letter A
Answer:
A.It lowers the melting point of alumina. B.It increases the electrical conductivity. ... Hint: The solution of alumina and cryolite during the electrolysis gives the aluminium at cathode and oxygen at anode. The alumina is a poor conductor of electricity and the fusion temperature of alumina is about 2000∘C.
The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
Protons and neutrons are in the center of the atom, making up the nucleus. Electrons surround the nucleus. Protons have a positive charge.
Each element has a specific mass number and a specific atomic number. These two numbers are fixed for an element. The mass number tells us the number (the sum of nucleons) of protons and neutrons in the nucleus of an atom. it has mass number 235 , it means that the sum of neutrons and protons in a carbon atom is 235.3
2.1653 g
Explanation:
The molar mass of Rubidium is;
85.468 g/mol
Therefore the moles of Rubidium that reacted with oxygen is;
1.98 / 85.468
= 0.0232 moles
If every two moles of Rubidium reacts with one mole of oxygen then the amount of oxygen consumed in the chemical reaction is;
0.5 * 0.0232
= 0.0116 moles
The molar mass of an oxygen atom is 16 g/mole. Then the amount of O in grams consumed is;
0.0116 * 16
=0.1853 g
The final weight of the Rubidium II Oxide is;
1.98 + 0.1853
= 2.1653 g
