Moles of water atoms = mass/molecular weight = 105/18 = 5.83 mol. Number of moles of hydrogen in water = 2 x moles of water = 11.66. Number of H atoms in water = moles of hydrogen x 6.02 x 10^23 = 7.019 x 10^24 ~ 7.02 x 10^24 atoms. Hope this helps.
of oxygen at STP would be required to react completely with 38.8g of propane.
<u>Given that :</u>
molar mass of propane = 44 g/mol
mass of propane = 38.8 g
∴ Moles present in 38.8 g of propane =
= 0.88 mole
<u>applying rule of balanced equations </u>
1 mole of propane = 5 moles of oxygen
0.88 mole of propane = 5 * 0.88 = 4.4 moles of oxygen
Note : volume of 1 mole of oxygen at STP = 
∴Total volume of oxygen required at STP = 22.4 * 4.4 = 
Hence we can conclude that the volume of oxygen at STP required to react completely 
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Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
J.J Thompson’s model shows a sphere with electrons that are moving around freely. However, Thompson’s model does not show protons or neutrons. The model that we have today gives a clearer structure showing protons, neutrons, and electrons inside an atom.
The theoretical yield of Ca(OH)₂ : 42.032 g
<h3>Further explanation</h3>
Given
31.8 g of CaO
Required
The theoretical yield of Ca(OH)₂
Solution
Reaction
CaO + H₂O⇒Ca(OH)₂
mol CaO (MW=56 g/mol) :
= mass : MW
= 31.8 g : 56 g/mol
= 0.568
From equation, mol Ca(OH)₂ = mol CaO = 0.568
Mass Ca(OH)₂ (MW=74 g/mol) :
= 0.568 x 74
= 42.032 g