Question

1. What are the rules for writing the symbol of an element? 2. Explain relative atomic mass and relative molecular mass. 3. What is the relationship between mole, Avogadro number and mass? 4. How do atoms exist? 5. Define a mole. What is the importance of a mole? 6. Calculate the mass of one atom of oxygen 7. Calculate the mass of one ion of oxygen 8. What do you understand by atomic mass and Gramatomic mass of an element? 9. The formula of water is H20. What do you understand by this formula? 10. State the Law of conservation of mass and the Law of constant proportion with examples.​

Answer 1

Explanation:

1. An element symbol is one - two letter - abbreviation for a chemical element name . When a symbol consists of two letters, the first letter is always capitalized ,while the second letter is lowercase. Scientists standardized the short handed way to represent element, by their chemical symbol.
2. Relative molecular mass of a substance is the average mass of a molecule of the substance when compared with one twelfth of the mass of one carbon-12 atom. ... Therefore, the relative molecular mass of a substance is calculated by adding up the relative atomic masses of all the atoms present in a molecule of the substance.
3. Avogadro's number is an absolute number: there are 6.022×1023 elementary entities in 1 mole. This can also be written as 6.022×1023 mol-1. The mass of one mole of a substance is equal to that substance's molecular weight.
4. Atoms exist in free states in the form of molecule. ... Molecules may be formbed by the combination of atoms of two or more different elements. For example molecule of water. It is formed by the combination of two atoms of hydrogen and one atom of oxygen.
5. A mole is defined as the amount of substance containing the same number of discrete entities (atoms, molecules, ions, etc.) ... The mole provides a link between an easily measured macroscopic property, bulk mass, and an extremely important fundamental property, number of atoms, molecules, and so forth.
6. The mass of an oxygen atom = 16 amu. ∴ Mass of O2 molecule = 2 × 16 = 32 amu.
7. Mass refers to the measure of number of atoms in an element or a compound. Now, since 1 mole of oxygen atoms = 16 units and every mole of oxygen contains 6.023 × 1023 atoms, Hence, 1 oxygen ion weighs = 1/6.023 × 1023 u.
8. The atomic mass of an atom of an element is expressed in atomic mass unit and may be defined as the total number of protons and neutrons present on that element. The gram atomic mass is defined as the amount of substance in gram and it is numerically equal to its atomic mass.
9. Chemistry The chemical formula for water is H2O. This formula means that there are two hydrogen atoms and one oxygen atom in each molecule of water. If x represents the number of oxygen atoms in a glass of pure water, express the number of hydrogen atoms in the glass of water in terms of the number of oxygen atoms.
10. Laws of conservation of mass – It states that mass can neither created nor destroyed. The total mass before and after a chemical reaction remains constant.