Say the dereference between the two is that "Exo" means "outside" and "Endo" means "inside" meaning one pulls heat inside (endothermic) and the other expels heat (exothermic)
Answer:
0.0522 mol NaSo4
Explanation:
3.148 x 10^22 Formula units NaSo4 * 1 mol NaSo4 / 6.02 x 10^23 Formula units NaSo4 = 0.0522 mol NaSo4
The combination of gases that surround and protect the Earth is the ATmosphere
Answer:
He developed the concept of concentric electron energy levels
Explanation:
Before Bohr's model, Rutherford's model was proposed. This model explains most of the properties of the atom but failed to explain the stability of the atom.
As per Rutherford's model, electrons revolve around the nucleus in the orbit.
But revolving electron in their orbit around nucleus would give up energy and so gradually move towards the nucleus and therefore, eventually collapse.
Bohr's proposed that the electrons around the nucleus move orbit of fixed energy called "stationary states". Electrons in these stationary states do not radiate energy.
Therefore, proposal of concentric electron energy levels refine the atomic models.
<span>14.2 grams
Let's start by looking up the atomic weights of aluminum and oxygen.
Atomic weight aluminum = 26.981539
Atomic weight oxygen = 15.999
Moles Al = 7.5 g / 26.981539 g/mol = 0.277967836
The formula for aluminum oxide is Al2O3, so for every 2 moles of Al, 3 moles of O is required. So let's calculate the number of moles of O we need and from that the mass.
0.277967836 mol / 2 * 3 = 0.416951754 mol
Mass O2 = 0.416951754 * 15.999 = 6.670811105
The mass of aluminum oxide is simply the mass of aluminum plus the mass of oxygen. So:
7.5 g + 6.670811105 g = 14.17081111 g
Rounding to 1 decimal place gives 14.2 g.</span>
