Answer:
3.64g
Explanation:
Given parameters:
Mass of NH₃ = 18.1g
Mass of Cu₂O = 90.4g
Unknown:
Limiting reactant = ?
Mass of N₂ formed = ?
Solution:
The reaction equation is given as:
Cu₂O + 2NH₃ → 6Cu + N₂ + 3H₂O
The limiting reactant is the one in short supply in the reaction. Let us find the number of moles of the given species;
Number of moles = 
Molar mass of Cu₂O = 2(63.6) + 16 = 143.2g/mol
Molar mass of NH₃ = 14 + 3(1) = 17g/mol
Number of moles of Cu₂O = 
= 0.13moles
Number of moles of NH₃ = 
= 5.32moles
From this reaction;
1 mole of Cu₂O combines with 2 mole of NH₃
So 0.13moles of Cu₂O will combine with 0.13 x 2 mole of NH₃
= 0.26moles of NH₃
Therefore, Cu₂O is the limiting reactant. Ammonia is in excess;
Mass of N₂;
Mass = number of moles x molar mass
1 mole of Cu₂O will produce 1 mole of N₂
0.13 mole of Cu₂O will produce 0.13 mole of N₂
Mass = 0.13 x (2 x 14) = 3.64g
Answer: The correct sequence for the series of event would be.
1. Igor's toe is being cut by the glass.
2. The wound surrounding the injury becomes infected with bacteria from Igor's foot.
3. Antibodies and circulating white blood cells stick to the bacteria creating a large complex in the lymph vessel.
4. The bacteria enter his lymph system and travel towards a lymph node.
5. The complex becomes trapped in a lymph node and is engulfed by a phagocyte.
6. The bacteria is destroyed.
Explanation:
Whenever there is any cut or wound in the body and body encounters invasion of the foreign materials it considers it as harmful pathogen.
These pathogens when enters the body it is considered as antigen, it then travels to the lymphatic system.
These bacterial complex is then killed by the phagocytes and digested by the body.
In this way the complex is killed and the bacteria is destroyed.
27/208 = normality
12 x 10^-2 approx = normality
nw Ka = 14.3 x 10^-3
pKa = 3 - log 14
now, after getting the pKa put it in formula :
pH = pKa + log concn of ion/concn of salt and you'll get it
hope this helps
