Answer:
Model 2 and model 3
Explanation:
Both atomic models represent hydrogen, which consists of one proton in the nucleus. Both atomic models consists of 1 proton, which means that both their atomic numbers are equal to 1
No. of moles = mass / molecular weight
n = m / Mr
n = 3 g / 23 g/mol
n = 0.13 mol / 4
n = 0.0326 mol
Mr of Na2O = 23+23+16 = 62 g/mol
n = 0.0326 mol x 2 (because you have 2x Na2O) = 0.0652 mol
m = n x Mr
m = 0.0652 mol x 62 g/mol
m = 4.04 g
Air is a mixture of elements which are formed my atoms that forms molecules. Hope that helps!
Answer:
C. hydration number
Explanation:
When we dissolve an ionic compound (a charged species) the charges can <u>interact with the water molecule</u>. In the case of <u>cations</u> (positive charges) the negative <u>dipole</u> of water (generated in the oxygen) will interact with the positive charge at the same time the <u>anions</u> (negative charges) the positive <u>dipole</u> of water (generated in the hydrogen).
The amount of water molecules that can interact with a single ion (cation or anion) is called <u>hydration number</u>. In the example, we have a hydration number of "4" for the sodium cation.
I hope it helps!