Organic Compounds Past Paper PDF

## Organic Compounds 1. We can say that organic compounds: - Are formed by carbon. - Are formed by the union of all the elements in the periodic table - Are maintained together by covalent bonds. **Answer:** B. I and III are correct. 2. A characteristic that makes carbon ver...

## Organic Compounds 1. We can say that organic compounds: - Are formed by carbon. - Are formed by the union of all the elements in the periodic table - Are maintained together by covalent bonds. **Answer:** B. I and III are correct. 2. A characteristic that makes carbon very special is that: - Present concatenation. - It forms ionic compounds. - Forms two covalent bonds. - Is present in all compounds. **Answer:** A. Present concatenation 3. The compound A melts at -28.15°C, while compound B melts at 851°C; the first doesn't dissolve in water, different from the second which does dissolve, this substances have: - A low fusion point, B high fusion point. - B most present concatenation and isometry. - A is an organic compound and B is an inorganic compound. **Answer:** C. I and III are correct. 4. The property that carbon presents to have compounds with the same molecular formula but different spatial arrangement is called: - Isometry - Solubility - Concatenation - Density **Answer:** A. Isometry 5. Characteristic of organic compounds: - Conduct electricity - Not flammable - Not soluble in water - Most are soluble in water **Answer:** C. Not soluble in water 6. From the following physical properties, choose the one which CH₃-CH₂-CH₃ doesn’t have: - More dense than water - Insoluble in water - Presents isometry - Formation of chains **Answer:** A. More dense than water. 7. An example of an inorganic compound is: - Proteins - Water - Gasoline - Natural gas **Answer:** B. Water ## Table 1. Physical properties of some organic compounds. | Compound | Name | Molecular weight (gr) | Boiling point (°C) | |:----------|:-------------|:----------------------|:--------------------| | CH₄ | Methane | 16 | -164.0 | | CH₃CH₃ | Ethane | 30 | -89.0 | | CH₃CH₂CH₃ | Propane | 44 | -42.0 | | CH₃OH | Methanol | 32 | 64.5 | | CH₃CH₂OH | Ethanol | 46 | 78.3 | | CH₃CH₂CH₂OH| Propanol | 60 | 97.0 | 8. Identify the compound with the highest boiling point: - Methane - Ethanol - Methanol - Propanol **Answer:** D. Propanol 9. The difference between the boiling point of methane and ethane is: - 92°C - 14°C - 30.5°C - 32.5°C **Answer:** C. 30.5°C 10. The relation between the molecular weight and boiling point of alcohols is that the higher the molecular weight, the lower the boiling point. - False - True **Answer:** A. False ## Open Questions: 1. Distinguish between organic and inorganic compounds: - **Organic Compounds** - Low melting points - Isomers present - Denser (than water) - Form covalent bonds. - Most are not soluble in water. - **Inorganic Compounds** - High melting points - Isomers not present - Denser than water - Form covalent and ionic bonds - Most are soluble in water.