Answer:
16 because carbon atom having usual 6 neutron have a mass number of 12 and that with 7 neutron has mass number of 13
You put precipitation in the wrong place the answer is D+A (number 4)
John Dalton made some hypothesis about the structure of atom. He proposed that matter is composed of great number of indivisible particles called atoms they can neither be destroyed nor be created.
<h3>What is atomic theory?</h3>
There are different theories regarding the structure and electronic properties of an atom. Many scientists contributed to the modern theory of atomic structure in which John Dalton was first to mention the word atom.
According to Dalton' theory, matter is composed of indivisible particles called atoms. Atoms can neither be created nor be destroyed. All the atoms of the same element are identical in all aspects.
Atoms of different elements are different and the compounds are formed by the combination of atoms. Dalton's theory provided a sound basis for the laws of chemical combination and also several properties of gases and liquids known at that time.
However, he could not explain the reason for chemical combination of atoms and did not give any idea about the existence of isotopes and isobars.
Hence, the main aspects of Dalton's theory was the indivisibility of atoms and the chances of chemical combination.
To learn more about Dalton's theory, find the link below:
brainly.com/question/11855975
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Answer:
The molarity is 0.56
Explanation:
In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes. Then, the molarity or molar concentration is the number of moles of solute per liter of solution.
In other words, molarity is the number of moles of solute that are dissolved in a given volume.
The Molarity of a solution is determined by:

Molarity is expressed in units (
).
Then you must know the number of moles of Cu(NO₂)₂. For that it is necessary to know the molar mass. Being:
-
Cu: 63.54 g/mol
- N: 14 g/mol
- O: 16 g/mol
the molar mass of Cu(NO₂)₂ is:
Cu(NO₂)₂= 63.54 g/mol + 2*(14 g/mol + 2* 16 g/mol)= 155.54 g/mol
Now the following rule of three applies: if 155.54 g are in 1 mole of the compound, 225 g in how many moles are they?

moles= 1.45
So you know:
- number of moles of solute= 1.45 moles
- volume=2.59 L
Replacing in the definition of molarity:

Molarity= 0.56
<u><em>The molarity is 0.56</em></u>
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