Here are the some important question for class 10th chapter 1 Chemical Equations
Important Questions –
Ques-1 What do you mean by exothermic and endothermic reactions ? Give examples.
Ques-2 Why is respiration considered an exothermic reaction ? Explain.
Ques-3 What is a balanced chemical equation ? Why should the chemical equations be balanced.
Ques-4 Explain the following in terms of gain of oxygen or loss of oxygen with two examples each:
- Oxidation Reaction.
Ques-5 Give reasons for the following
- When copper turnings are added to silver nitrate solution, the solution becomes blue in the colour after some time.
- Blue colour of copper sulphate solution fades when iron filings are added to it.
Ques-6 Oil and fat containing food items are flushed with nitrogen. Why?
Ques-7 What are decomposition reaction ? Explain with examples.
Ques-8 What are the difference between displacement and double displacement reactions ? Write equations for these reactions.
Ques- 9 Define Oxidising agent and reducing agent in terms of electronic concept of Oxidation and Reduction.
Ques-10 What happens when a piece of
- Zinc metal is added to copper sulphate solution ?
- Aluminium metal is added to diluite hydrochloric acid.
- Silver metal is added to copper sulphate solution.
Ques- 11 On heating blue coloured powder of copper(II) nitrate in a boiling tube, copper oxide ( black) , oxygen gas and a brown gas ‘X’ is formed.
- Write a balanced chemical equation of the reaction.
- Identify the brown gas X evolved.
- Identify the type of reaction.
- What could be the PH range of aqueous solution of the gas X ?
Ques -11 On adding a drop of barium chloride solution to an aqueous solution sulphite, white precipitate is obtained.
- Write a balanced chemical equation of the reaction involved.
- What other name can be given to this precipitation reaction ?
- On adding dilute hydrochloric acid to the dilute mixture, White precipitate disappears why?
Ques 12 During the reaction of some metals with dilute hydrochloric acid, following observations were made.
- Silver metal does not show any change.
- The temperature of the reaction mixture rises when alluminium (AL) is added.
- The reaction of sodium metal is found to be highly explosive.
- Some bubbles of a gas are seen when lead (PB) is reacted with the acid.
Explain these observations giving suitable reasons.
Ques 13 Which among following are physical or chemical changes?
- Evaporation of patrol.
- Burning of liquefied petroleum Gas (LPG).
- Heating of an iron rod to red hot.
- Curdling of milk.
- Sublimation of solid ammonium chloride.
Ques-14 A shiny brown coloured element ‘X’ on heating in air beomes black I colour. Name the element ‘X’ and the black coloured compound formed ?
Ques-15 Write the balanced chemical equations for the following reactions:
- Calcium hydroxide + Carbon dioxide ——–à Calcium carbonate + water
- Zinc + Silver Nitrate à Zinc Nitrate + Silver
- Aluminium + Copper Chloride à Aluminium chloride + Copper
- Barium chloride +potassium sulphate à Barium sulphate + Potassium chloride.
Ques-15 Ethane burns in oxygen to form carbon dioxide and water. Write balanced chemical equation for the reaction.
Ques-16 Calcium reacts with nitrogen to form calcium nitride. Write balanced chemical reaction.
Ques-17 In the formation of a compound XY, atoms of element X lose two electrons each while the atoms of element Y gain two electrons each Identify.
- The element undergoing oxidation.
- The element undergoing reduction.
- The element acting as oxidising agent.
- The element acting as reducing agent.
Ques-18 Translate the following statements into chemical equations and then balance them.
- Hydrogen gas combines with nitrogen to form ammonia.
- Hydrogen sulphide gas burns in air to give water and Sulphur dioxide.
- Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
- Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.