1. Define polyatomic ion. Give one example.
2. What is formula unit of mass? How is it different from molecular mass?
3. What is Law of conservation of mass and Law of constant proportions?
4. What is an ion? Explain the types of ion with examples.
5. Find the molecular mass of H2O.
6. Define the term valency. What is the valency for magnesium and copper?
7. What is the difference between cation and anion?
8. What is atomicity? What is the atomicity of phosphorus and nitrogen?
9. Find the number of atoms in 0.5 mole of C atom.
10. Find the mass of 1.5 mole of CO2 molecule.
11. Calculate the formula unit mass of NaCl and CaCl2.
12. What is the difference between molecules 2O and O2?
Answers
Answer:
1. polyatomic ions are ions which consists of more than one atom. for ex-niterate
Explanation:
1. Polyatomic ions are ions which consist of more than one atom . For example, nitrate ion, NO3, contains one nitrogen atom in a polyatomic ion are usually covalently bonded to one another, and therefore as a single, charged unit.
2. Formula mass is defined as the sum of atomic masses of the ions present in the formula unit of an ionic compound while molecular mass is the sum of the atomic masses of the atoms in a molecule. Formula mass is more general term than molecular mass and may be used in referring to all compounds but not the molecular mass.
3. 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.
Laws of constant proportion:- It states that in a chemical substance the elements are always present in a fixed proportion by their mass.
4. An ion is a positively or negatively charged atom (or group of atoms). An ion is formed by the loss or gain of electrons by an atom, so it contains an unequal numbers of electrons and protons.Two types of ions are:-
Cation:- Formed by the loss of the electrons. Example:- Na+Mg++2.
Anion:- Formed by the gain of the electrons. Example:- Cl, O--