CBSE SOLVED TEST PAPERS CLASS - IX Science (Is matter around us pure) Q. What is distillation? Ans: Distillation is a method of separating mixtures based on differences in their boiling points. The compound... read
Class 09 Atoms and Molecules Numerical Problem based on Law of chemical Combination Law of conservation of mass Law of constant proportion Empirical formula 1. If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mass.(Based on Law of conservation of mass) Solution: Mass of the reactants = 10g ; Mass of the products = 4.4 + 6.6g = 10g Since the mass of the reactants is equal to the mass of the products, the observations are in agreement with the law of conservation of mass. 2. 1.375 g of cupric oxide was reduced by heating and the weight of copper that remained was 1.098g. In another experiment 1.179 g of copper was dissolved in nitric acid and the resulting copper nitrate was converted into cupric oxide by ignition . The weight of cupric oxide formed was 1.476 g. which law of chemical combinations does this data state? Solution: in first experiment: Copper oxide = 1....
I am not in favor of this new exam pattern.Its totally an injustice to the regional board aspirants.Its a well known fact that CBSE's marking system is comparatively easier than other regional boards.So,definitely CBSE candidates will score more in ISEET.
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