Periodic table


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Carbon. Class 8 chemistry. Long Q&A

10. Question: Carbon dioxide occurs both in the free state and in the combined state. State three methods how carbon dioxide is added to the atmosphere. Answer: Three methods are: - Through respiration by living organisms - Combustion of fossil fuels - Volcanic eruptions and natural decomposition of organic matter 11. Question: In the laboratory preparation of carbon dioxide by action of a dilute acid on a metallic carbonate give: a) A balanced equation for the preparation  b) A reason for i) use of a wash bottle containing conc. H2SO4 ii) Not collecting the prepared gas over water iii) Not using dilute sulphuric acid as a reactant in the preparation. Answer: a) CaCO3 + 2HCl → CaCl2 + H2O + CO2 b) Reasons: i) Wash bottle with conc. H2SO4: To dry the gas ii) Not collected over water because CO2 is slightly soluble in water iii) Dilute H2SO4 isn't used because CaSO4 formed is insoluble and coats unreacted carbonate 12. Question: How would you prove experimentally that a) Carbon dioxi...
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