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Class 10 · Science · Hard
→In the reaction of calcium oxide with water, only one product is formed and heat is released. What is the correct combined classification of this reaction?
Class 10 · Science · Hard
→Why is it incorrect to change the subscripts in the formula of a compound while balancing a chemical equation?
Class 10 · Science · Hard
→In the balanced equation for burning magnesium, \(2\mathrm{Mg}+\mathrm{O}_2\rightarrow2\mathrm{MgO}\), how many oxygen atoms are present on the product side?
Class 10 · Science · Medium
→In the balanced chemical equation 2H₂ + O₂ → 2H₂O for the formation of water, how many hydrogen atoms are present in total on the product side?
Class 10 · Science · Hard
→If a gas is produced during a chemical reaction, what precaution should be taken while verifying the law of conservation of mass?
Class 10 · Science · Hard
→In a closed container, a total of 20 g of reactants undergo a reaction to form products, and any gas produced remains inside the container. What will be the total mass of the products?
Class 10 · Science · Hard
→In the reaction CuO + H₂ → Cu + H₂O, which is the correct identification of oxidation and reduction?
Class 10 · Science · Medium
→In which situation will checking conservation of mass be most reliable?
Class 10 · Science · Hard
→In the reaction \(CuO + H_2 \rightarrow Cu + H_2O\), which substance is the reducing agent?
Class 10 · Science · Hard
→Which of the following reactions is both a displacement reaction and a redox reaction?
Class 10 · Science · Hard
→Which statement correctly identifies oxidation and reduction in the reaction \(\mathrm{CuO + H_2 \rightarrow Cu + H_2O}\)?
Class 10 · Science · Hard
→What is the correct difference between the aqueous symbol \((aq)\) and the liquid symbol \((l)\) in a chemical equation?
Class 10 · Science · Hard
→In a chemical equation, what do a downward arrow \(\downarrow\) and an upward arrow \(\uparrow\) written with products respectively indicate?
Class 10 · Science · Medium
→If gas evolves in an unknown reaction but colour does not change what will be the most careful conclusion?
Class 10 · Science · Hard
→In which situation should a colour change not be considered evidence of a chemical reaction?
Class 10 · Science · Hard
→On what basis can the formation of curd from milk and the formation of ice from water be differentiated?
Class 10 · Science · Hard
→On what basis are chewing food and digesting it different?
Class 10 · Science · Hard
→When a clean iron nail is placed in a blue \(CuSO_4\) solution, a reddish-brown coating forms on the nail. Which conclusion correctly explains this change?
Class 10 · Science · Hard
→Why are both combustion and respiration considered exothermic processes?
Class 10 · Science · Medium
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