Answer: (a) There are 0.428 moles present in 12 g of 
molecule.
(b) There are 2 moles present in 
particles of oxygen.
Explanation:
(a). The mass of nitrogen molecule is given as 12 g.
As the molar mass of is 28 g/mol so its number of moles are calculated as follows.
So, there are 0.428 moles present in 12 g of molecule.
(b). According to the mole concept, 1 mole of every substance contains 
atoms.
Therefore, moles present in particles are calculated as follows.
So, there are 2 moles present in particles of oxygen.
"John Dalton" is the one scientist among the following choices given in the question that <span>came up with the first widely recognized atomic theory. The correct option among all the options that are given in the question is the first option or option "A". I hope that this is the answer that has come to your help.</span>
Answer:
c. crystallization
Explanation:
The opposing process that occur in a solution in contact with undissolved solute are dissolution and crystallization.
In the dissolution process the solid substance coverts into liquid state and mixes with solution. Whereas in Crystallization the the chemical is converted from the liquid solution to solid crystal state.
D, the rate increases as concentrations increase.
Typically, reaction rates decrease with time because reactant concentrations decrease as reactions are converted to products. Reaction rates generally increase when reactant concentrations are increased.
Answer: The volume of 
required is 25.0 ml
Explanation:
According to the neutralization law,
where,
= basicity 
= 1
= molarity of solution = 2.00 M
= volume of solution = 50.0 ml
= acidity of = 1
= molarity of solution = 4.00 M
= volume of solution = ?
Putting in the values we get:
Therefore, volume of required is 25.0 ml
