<u>We are given:</u>
Mass of Na added = 4.35 grams
Mass of water = 105 grams
<u>Mass Percent of Na:</u>
Total mass of the solution = mass of solute + mass of solvent
Total mass of the solution = 4.35 + 105 = 109.35 grams
Mass percent of solute = (mass of solute / mass of solution) * 100
Mass percent of Solute = (4.35 / 109.35) * 100
Mass percent = 3.978 %
Answer:
1.18×10²³ atoms.
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms.
From the above concept, 1 mole of sodium also contains 6.02×10²³ atoms.
1 mole of sodium = 23 g.
Thus,
23 g of sodium contains 6.02×10²³ atoms.
Therefore, 4.5 g of sodium will contain = (4.5 × 6.02×10²³)/23 = 1.18×10²³ atoms.
From the above calculation,
4.5 g of sodium contains 1.18×10²³ atoms.
Answer:
The energy difference between these 2p and 2s orbitals is 
Explanation:
Wavelength of the photon emitted = 
Energy of the photon will corresponds to the energy difference between 2p and 2s orbital = E
Energy of the photon is given by Planck's equation:

h = Planck's constant = 
c = Speed of the light = 


The energy difference between these 2p and 2s orbitals is 
Answer:
Darwin had arrived at a complete theory of evolution by 1839, but it was to be another 20 years before he published his ideas of evolution through natural selection in his epochal book On the Origin of Species by Means of Natural Selection.
The number is 3
because if the number was x it would be 3x=x+6
And x=3