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Answer:
In a neutral molecule, the sum of the bonding valance electrons must be equal. So the products of the negative element and its charges and the positive element and its charge must be equal.
Explanation:
C1×N1 = C2×N2
If we have a 3 valance electrons , the 'A' charge will be either +3 or -5 for a full octet and valance electron in 'B' atoms will mostly result in acquisition of additional electrons (2) for an octet and relative charge of -2.
Balancing the two,
3 × A = -2 × B
To be equal, A = 2 and B = 3
Therefore, A²B³
Here we go ~
1 mole of 
has 6.022 × 10²³ molecules of the given compound.
So, 0.78 mole of 
will have ~
Answer:
If one element is a metal and the other element is a non metal
Explanation:
Ionic bonds are formed between metals and non metals. The nonmetal atom receives electron(s) from a metal atom to form an ionic substance. This means that ionic substances are basically an ion pair.
Covalent bonds are mostly formed between two nonmetals. These elements share electrons with each other in order to form the compound.
Answer: 1.8124 g of 3-nitrophthalhydrazide were recovered.
Explanation:
The balanced chemical reaction will be :
moles of 3-nitrophthalic acid = 
As 1 mole of 3-nitrophthalic acid gives = 1 mole of 3-nitrophthalhydrazide
0.0110 moles of 3-nitrophthalic acid gives = 
mole of 3-nitrophthalhydrazide
mass of 3-nitrophthalhydrazide = 
As the percentage yield is 93% , the mass of 3-nitrophthalhydrazide recovered = 
Therefore 1.8124 g of 3-nitrophthalhydrazide were recovered.
