Question

CHEMISTRY: A. Complete the following chemical equations and balance them. 1. Mg + O2 → 2. Zn + H2SO4 → 3. Fe + H2O (g) → 4. CO + H2(g) → 5. CO2 + H2O → 6. CaO + H2O → 7. C + O2 → 8. H2 + O2 → 9. C H4 + O2 → 10. C6 H12O6 + O2 → 11. FeSO4 → 12. CaCO3 → 13. Pb ( NO3 )2 → 14. AgCl → 15. AgBr → 16. Fe + CuSO4 → 17. Zn + CuSO4 → 18. Pb + CuCl2 → 19. Zn + Na2 SO4 → 20. BaCl2 + Na2 SO4 → 21. Cu + O2 → 22. CuO + H2 →

Answer 1

Answer:

The wax acts as a fuel when we light the candle and is basically carbon. The carbon combines with oxygen to form another chemical substance which is carbon dioxide. Also the unburnt carbon is deposited as black substance called soot. This signifies a chemical change.

A-35) When solutions of barium chloride and sodium sulphate are mixed together, then an insoluble precipitate of barium sulphate and solution of sodium chloride is obtained. Hence, this reaction is a precipitation (a kind of double displacement reaction) reaction. The chemical equation for reaction between barium chloride and sodium sulphate is represented as follows

BaCl2 + Na2SO4 → BaSO4 + 2NaCl

A-38) Pure water is very weakly ionised and hence does not conduct electricity very well. Sulphuric acid basically increases the conductivity of water, and thereby speeds up the process of electrolysis. However it does not affect the chemical composition of the reactant or products, it only increases the speed of the reaction. Thus it plays the role of a catalyst.

A-44) The said compound is lead nitrate. It is white in colour. When lead nitrate is heated, it decomposes to give lead oxide, nitrogen dioxide and oxygen. Nitrogen dioxide is a brown coloured gas. The chemical equation involved in the reaction is :



 

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Priya G N answered this

3159 helpful votes in Science, Class XII-Science

You are not supposed to ask so many questions in a single query. Ask each question separately.

I am answering your 15th and 20th question.

15. The balanced equation is:

MnO2 (s) + 4HCl (aq) ==> MnCl2 (aq) + 2H2O (l) + Cl2 (g)

20. The water insoluble substance (A) is calcium carbonate CaCO3. On reacting with dilute H2SO4 released a colourless and odourless gas accompanied by a brisk effervescence which is carbon dioxide (B).

CaCO3 (s) + H2SO4 (aq) ---------> CaSO4(aq) + H2O (aq) + CO2 (g)

  (A)   (B) 

On bubbling the CO2 gas (B) through lime water (calcium hydroxide) the solution became milky and again forms compound (A) i.e calcium carbonate.

Ca(OH)2 + CO2 (g)----------------->CaCO3 (s) + H2O (l)

   (B)  (A) (milky)

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18



Swiffty Maitree answered this

20 helpful votes in Science, Class XI-Science

1. Zn+ H2SO4= ZnSO4+ H2

2. Zn oxidised C is reduced

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