According to the concept of Avogadro's number, there are 1.505×10²³ molecules in 0.25 mole of O₂.
Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number
Number of molecules is obtained by multiplying number of moles and Avogadro's number , that is 0.25×6.023×10²³=1.505×10²³ molecules.
Thus, there are 1.505×10²³ molecules in in 0.25 mole of O₂.
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The electron is the primary atomic particle that determines an atom's chemical behaviour.
Electrons are negatively charged particles that form electron shells or energy levels around an atom's nucleus. They are engaged in the production and breaking of chemical bonds, hence they play an important part in chemical reactions.
The quantity and configuration of electrons in an atom's outermost energy level (valence electrons) are very significant in determining the chemical characteristics of the atom. Because of the identical number of valence electrons, elements in the same group or column of the periodic table frequently show similar chemical behaviour.
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Boyle's law deals with pressure and volume.
Robert Boyle studied the relationship between the pressure p and the volume V of a confined gas held at a constant temperature.
Boyle observed that the product of the pressure and volume are observed to be nearly constant.
The product of pressure and volume is exactly a constant for an ideal gas.
PV = constant
As per Boyle’s law, any change in the volume occupied by a gas (at constant quantity and temperature) will result in a change in the pressure exerted by it. In other words, the product of the initial pressure and the initial volume of a gas is equal to the product of its final pressure and final volume (at constant temperature and number of moles).
Therefore, Boyle's law deals with pressure and volume.
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its atomic weight
its atomic formula
its atomic structure
Answer: Option (b) is the correct answer.
Explanation:
Atomic weight is also known as atomic mass or molar mass of an atom.
Atomic mass means the sum of total number of protons and neutrons present in an atom.
For example, atomic mass of HCl is atomic mass of hydrogen + atomic mass of chlorine.
That is, atomic mass of HCl is 1.01 g/mol + 35.453 g/mol = 36.463 g/mol
Thus, we can conclude that molar mass of any element is always equal to its atomic weight.
(2) 35.0% (4) 60.0%
Answer:
The correct option is (2) 35.0%
Explanation:
If we want to calculate the percent composition by mass of nitrogen in NH4NO3 we first need to calculate the mass of nitrogen in one mole of NH4NO3.
Because of the molecular form of NH4NO3 (it has 2 ''N'') we know that one mole of NH4NO3 contains 2 moles of N.
The molar mass of N (nitrogen) is
This means that 1 mole of N contains 14.0067 grams of N.
Because we have 2 moles of N ⇒
We know that in 1 mole of NH4NO3 we have 2 moles of N(28.0134 g of N).
To calculate the percent composition by mass of nitrogen we need to divide the mass of nitrogen in one mole of NH4NO3 by the mass of one mole of NH4NO3 and then multiply it by 100.
We know that in 1 mole of NH4NO3 there are 80.0 g of NH4NO3 (Because of the molar mass data) ⇒
% ≅ 35.0%
We find that the percent composition by mass of nitrogen in NH4NO3 is 35.0%
We conclude that the correct option is (2) 35.0%
The answer is NOT 4... I took the test!