Which of the following is correct definition of a mole?A. It is equal ...
Definition of a mole:
- The correct definition of a mole is option B: It contains 6.022×10^23 atoms of a given substance.
Explanation:
- The mole is a unit of measurement used in chemistry to represent a specific amount of a substance.
- It is defined as the amount of a substance that contains the same number of entities (atoms, molecules, ions, etc.) as there are atoms in 12 grams of carbon-12.
- The number of entities in a mole is known as Avogadro's number, which is approximately 6.022×10^23.
- Therefore, a mole represents a specific quantity of a substance, regardless of its atomic or molecular mass.
- The correct definition of a mole is that it contains 6.022×10^23 atoms of a given substance, as stated in option B.
Incorrect options:
A. It is equal to the gram atomic mass of the substance:
- This is not the correct definition of a mole. The gram atomic mass is the mass of one mole of atoms of an element, but it does not define what a mole is.
C. It is equal to the gram molecular mass of the substance:
- This is not the correct definition of a mole. The gram molecular mass is the mass of one mole of molecules of a compound, but it does not define what a mole is.
D. It contains 6.022×10^23 molecules of a given substance:
- This statement is incorrect because a mole can contain atoms, molecules, ions, or any other entities, not just molecules.
Which of the following is correct definition of a mole?A. It is equal ...
Calculation of Oxygen atoms in CaCO3:
To determine the number of oxygen atoms present in 300 grams of CaCO3, we need to follow these steps:
Step 1: Calculate the molar mass of CaCO3
- The molar mass of one Ca atom = 40.08 g/mol
- The molar mass of one C atom = 12.01 g/mol
- The molar mass of three O atoms = 3 x 16.00 g/mol
- Total molar mass of CaCO3 = 40.08 + 12.01 + 3(16.00) = 100.09 g/mol
Step 2: Calculate the number of moles in 300 grams of CaCO3
- Number of moles = Mass / Molar mass
- Number of moles = 300 g / 100.09 g/mol = 2.998 moles
Step 3: Calculate the number of oxygen atoms
- In one molecule of CaCO3, there are 3 oxygen atoms
- Number of oxygen atoms = 3 x Avogadro's number x Number of moles
- Number of oxygen atoms = 3 x 6.022 x 10^23 x 2.998
- Number of oxygen atoms = 54.207 x 10^23
Therefore, there are 54.207 x 10^23 atoms of oxygen present in 300 grams of CaCO3. Hence, the correct answer is option 'A'.
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