# The Language of Chemistry|Class 9

## List of anion or acidic radicals:

• Relative atomic mass:
• Relative molecular mass:
• % composition of an element:
• Empirical formula: The simplest formula possible for any compound in which atoms of the constituent elements are in a simple whole-number ratio.
• Molecular formula: The formula that shows the exact number of atoms of each of the constituent elements present in a molecule of any compound.

### Practice Set-1

• Find the empirical formula, molecular weight and empirical weight of the following-
1. Hg2(NO3)2
2. Na2S2O3
3. NH4NO2
4. (NH4)3PO4
5. H2S2O7
6. Fe2O3. 3H2O
7. C2H2Cl4
8. C6H12O6
9. C2H6
10. C2H4Br2                                                                            [5]

[Hg= 200, N=14,O=16,Na=23,S=32,H=1,P=31,Fe=56,Cl=35.5,C=12,Br=80]

• Write the formula of the following:
1. Ammonium sulphate
2. Aluminium phosphate
3. Calcium borate
4. Zinc nitride
5. Ferric sulphate
6. Sodium Sulphite
7. Magnesium bisulphide
8. Ferrous hydroxide
9. Cupric manganate
10. Ammonium dichromate                                      [5]
• Write the name of the following:
1. NaHSO4
2. K2ZnO2
3. Na2PbO2
4. (NH4)3PO4
5. Na2S2O3
6. Ca(MnO4)2
7. AlN
8. CaF
9. Fe(C2O4)
10. (CH3COO)Cu                                                                   [5]
• Sulfate of an element M is MSO4. Find the formula of its-
1. Hydroxide
2. Permanganate
3. Oxalate
4. Ferrocyanide
5. Nitrite
6. Acetate
7. Perchlorate
8. Bromide
9. Oxide
10. Nitride                                                                       [5]
• Balance the following:
1. MnO2 + HCl → MnCl2 + Cl2+ H2O
2. Na2S2O3 + HCl →NaCl + H2O + SO2 + S
3. NH4Cl  + Ca(OH)2 → CaCl2 + H2O + NH3
4. NH3 + P2O5 + 3H2O → (NH4)3PO4
5. Mg3N2 + H2O → Mg(OH)2 + NH3
6. NH3 + O2 → N2 + H2O
7. NH3  + CuO → Cu + H2O + N2
8. NH3 + Cl2 → N2 + NH4Cl
9. NH3 + Cl2 → HCl + NCl3
10. HNO3 → H2O + NO2 + O2
11. C + HNO3 → CO2 + H2O + NO2
12. S + HNO3 → H2SO4 + H2O + NO2
13. Cu +HNO3 → Cu(NO3)2 + H2O + NO
14. Cu + HNO3 → Cu(NO3)2 + H2O + NO2
15. Zn(NO3)2 → ZnO + NO2 + O2
16. S + H2SO4 → H2O + SO2
17. Cu + H2SO4 → CuSO4 + H2O + SO2
18. FeSO4 + H2SO4 + HNO3 → Fe2(SO4)3 + H2O + NO
19. P2O5 + HCl → POCl3 + HPO3
20. HNO3 + HCl → NOCl + H2O +[Cl]                                    [10]

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