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Questions in chemistry

[Terjawab] Which equation shows the proper setup to find the volume of a $0.250 M CaCl _2$ solution that contains 39.5 g or $CaCl _2$? $0.250 M CaCl _2=\frac{39.5 g CaCl _2}{V}$ $V=39.5 g CaCl _2 \times \frac{1 mol CaCl }{110.98 g CaCl _2} \times \frac{1 L}{0.250 mol CaCl _2}$ $V=\frac{39.5 g CaCl _2}{0.250 M CaCl _2}$

[Terjawab] Match List I with List II: List I: A. Coke B. Diamond C. Fullerene D. Graphite List II: 1. Carbon atoms are sp³ hybridised 2. Used as a dry lubricant 3. Used as a reducing agent 4. Cage like molecules Choose the correct answer from the options given below: (A) A-4, B-1, C-2, D-3 (B) A-3, B-1, C-4, D-2 (C) A-3, B-4, C-1, D-2 (D) A-2, B-4, C-1, D-3

[Terjawab] Select the correct answer. What are the products of the acid-base reaction between [tex]$HNO _3$[/tex] and NaOH? A. [tex]$H _2 O$[/tex] and [tex]$NaNO _3$[/tex] B. NaH and [tex]$NO _3 OH$[/tex] C. HNOH and [tex]$NaO _3$[/tex] D. NaOH and [tex]$HNO _3$[/tex]

[Terjawab] In manufacturing of Cl₂ gas, according to the reaction: HCl + O₂ \xrightarrow{CuCl₂} {Cl is one isotope of chlorine} The probable products for this reaction are: (i) Cl₂ + H₂O (ii) Cl₂ + H₂O (iii) Cl-Cl + H₂O Which of the above three set of products can actually be obtained? (A) only (i) (B) (i) & (ii) (C) only (iii) (D) (i), (ii) & (iii)

[Terjawab] 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

[Terjawab] 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

[Terjawab] 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.

[Terjawab] 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

[Terjawab] 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.

[Terjawab] 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