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Questions in chemistry

📝 Answered - What is the mass of KClO₃ (s) required to liberate 22.4 dm³ oxygen at STP during thermal decomposition? (Molar Mass of KClO₃ = 122.5 g/mol) A. 122.5 g B. 81.67 g C. 10.25 g D. 8.16 g

📝 Answered - Which of the following is the most important ingredient in the manufacture of soap? (a) Limestone (b) Caustic soda (c) Water (d) Perfume (e) Common salt

📝 Answered - 6.1 A sample of compound V contains 54.56% C, 9.09% H, and 36.35% O. 6.1.1 Define the term empirical formula. 6.1.2 Use calculation to determine the empirical formula of compound V. 6.2 When 150 g hydrated aluminium chloride (AlCl3.nH2O) is dried, its mass decreases by 89.595 g. 6.2.1 Define water of crystallisation. 6.2.2 Determine the value of n in AlCl3.nH2O.

📝 Answered - How many moles of each element are in one mole of [tex]$\left( NH _4\right)_2 S$[/tex]? A. 1 mole of nitrogen, 8 moles of hydrogen, 1 mole of sulfur B. 1 mole of nitrogen, 6 moles of hydrogen, 1 mole of sulfur C. 2 moles of nitrogen, 6 moles of hydrogen, 1 mole of sulfur D. 2 moles of nitrogen, 8 moles of hydrogen, 1 mole of sulfur

📝 Answered - Write 'true' or 'false': 1. Economic strength of a country depends upon the quality of its chemists. 2. Chemistry has solved most of the problems facing mankind. 3. Fertilisers increase food production. 4. Plastic is a good substitute of wood. 5. Diodes are used in improved fuels. 6. CFC is used in refrigerators as a coolant.

📝 Answered - Which of the following is described by the equation [tex]H _2 O (s)[/tex] + heat [tex]\rightarrow H _2 O (\Lambda)[/tex] ? A. Evaporating B. Freezing C. Condensing D. Melting

📝 Answered - How many grams of $CaCl_2$ are in 250 mL or $2.0 M CaCl_2$? $\square$ $g CaCl_2$

📝 Answered - How is pH used to determine if a solution is acidic or basic?

📝 Answered - What is the most appropriate action when confirming column degradation during method transfer? A. Proceed with analysis using adjusted method parameters B. Document observations and initiate column regeneration C. Update SOPs to include shorter column lifespan D. Perform system suitability with reference standard

📝 Answered - Practice exercise 1 Convert the following masses into kilograms. a) [tex]$58475 \mu g$[/tex] b) 406 dg e) 945 Dg f) 1854 mg i) 40500 g Express the following masses into decigram.