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which of the following are combustion reactions? CH _4 + O _2(g) rightarrow CO _

ID: 485454 • Letter: W

Question

which of the following are combustion reactions? CH _4 + O _2(g) rightarrow CO _2 (g) + H _20(I) CaO(s) + CO _2(g) rightarrow CaC0 _3(s) PbCO _3 (s) rightarrow PbO (s) + CO _2 (g) (CH _3OH (I) + O _2(g) rightarrow CO _2 (g) + H _2O (I) l and 4 1, 2, 3, and 4 1, 3, and 4 2, 3, and 4 3 and 4 Which of the following are decomposition reactions? CH _4 (g) + O _2(g) rightarrow CO _2(g) + H _2O (I) CaO(s) + CO _2 (g) rightarrow CaC0 _3(s) Mg (s) + 0 _2(g) rightarrrow MgO(s) PbC0 _3(s) rightarrow PbO (s) + CO _2 (g) 1, 2, and 3 4 only 1, 2, 3, and 4 2 and 3 2, 3, and 4 The formula of nitrobenzene is C _6H _5N O _2. The molecular weight of this compound is __________ amu- 107.11 43.03 109.10 123.11 3.06 The formula weigh, of potassium dichromate, K _2Cr _2O _7 is .____________ amu 107.09 255.08 242.18 294.18 333.08

Explanation / Answer

8. All combustion reaction takes place in presence of oxygen

   A. 1 and 4

9. In decomposition reaction one compound converted to two or three compounds

   PbCO3 ------------------> PbO + Co2

B. 4 only

10. C6H5No2

molecular weight of C6H5No2   = 6*12 + 5*1 + 1*14+2*16   = 123amu

D.123.11amu

11. formula weight of K2Cr2O7 = 2*39+2*52*7*16   = 294amu

D. 294.18amu