That would be A.
2.5*2*10^(10-7)=5*10^3
Answer:
d) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.
Explanation:
This is an example of a n-type semiconductor. The additional electron introduced to the 'grid' of silicon atoms causes an increase in the conductivity of the silicon. This additional electron is introduced as arsenic loses its extra electron.
Explanation:tr
a) Molar mass of HF = 20 g/mol
Atomic mass of hydrogen = 1 g/mol
Atomic mass of fluorine = 19 g/mol
Percentage of an element in a compound:
Percentage of fluorine:
Percentage of hydrogen:
b) Mass of hydrogen in 50 grams of HF sample.
Moles of HF = 
1 mole of HF has 1 mole of hydrogen atom.
Then 2.5 moles of HF will have:
of hydrogen atom.
Mass of 2.5 moles of hydrogen atom:
1 g/mol × 2.5 mol = 2.5 g
2.5 grams of hydrogen would be present in a 50 g sample of this compound.
c) As we solved in part (a) that HF molecules has 5% of hydrogen by mass.
Then mass of hydrogen in 50 grams of HF compound we will have :
5% of 50 grams of HF = 
Improper or incomplete usage of citations can lead to plagiarism.
Without proper usage of citations, teachers or whoever is looking over your work, may think because you do not hold acceptable citations, that they will think it is plagiarized. Plagiarism is taking another person's work or ideas without citing it. Citation or direct quotation could save you from plagiarism.
7.5 mol of hydrogen would be needed to consume the available nitrogen.
Explanation:
When hydrogen reacts with nitrogen, ammonia is formed as shown below;
3H₂ (g) + N₂ (g) → 2NH₃ (g)
As seen from the equation, every 3 moles of H₂ react with a mole of N₂ to form 2 moles of NH₃.
The limiting factor in a chemical reaction is the reactant that gets depleted first.
Because the molar mass of nitrogen gas is approximately 28g/mol, 70g of nitrogen gas would be 2.5 moles.
The reaction ratio of nitrogen to hydrogen in the reaction is 1 : 3. The reaction would require 2.5 * 3 (7.5) moles of hydrogen for a complete reaction.
However since there are only 7g on hydrogen, (Remember 1 mole of H₂ is approximately 2g), the available moles of H₂ is 7 / 2 = 3.5
3.5 moles fall short of the 7.5 moles of H₂ required for a complete reaction. H₂ gets depleted first before N₂. The reaction would require 4 more moles of H₂.
