Carbon burns in oxygen to form carbon dioxide. The properties of carbon dioxide are -

(D) Helium or nitrogen To prevent rancidification of foods containing fats and oils, the packed food is surrounded by unreactive gas (like helium, nitrogen, etc.). The inert atmosphere thus created prevents...

(C) carbon dioxide only

Molecular mass of CO2 = 12 + 2 x 16 = 44  1mol of CO2 = 44 g  44 g of CO2 contain = 6.022 x 1023 molecules  88 g of CO2 contain...

Apply Boyle’s Law P1 V 1= P 2 V 2   200 x 10 = 1 x V 2   V2 =2000 L   No. of breaths = Total volume/ vol. consumed per breath   =2000/0.5x10 -3 L  =4x106

(d) Acid rain is caused by a chemical reaction that begins when compounds of sulphur dioxide and nitrogen oxide react with molecules in the atmosphere to produce acids.

Calculation of mass of CO2 produced:  Mass of compound =0.20g  %C =12 x C  69=12*mass of CO2 formed*100/44*0.2  Mass of CO2 formed =69*44*.2/12*100  = 0.506g  Similarly, % H =2* mass of H2O formed*100/18*mass of compoun 4.8=2* mass...

(B) constant proportions

(i) Substance X- Calcium Hydroxide. Ca(OH)2(aq) + CO2(g)  → CaCO3(s) H2O (ii) Calcium hydroxide is obtained by reaction of calcium oxide and water. CaO(s) + H2O(l) → Ca(OH)2(aq) + Heat 

(i) Substance X is lime water. Ca(OH)2 + CO2 → CaCO3 + H2O Ca(OH)2  -(Lime water) CO2   -(Carbon dioxide) CaCO3 -(Calcium carbonate) H2O - (Water) (ii) Calcium oxide reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of...

(i) X(20) ---2,8,8,2 It is calcium. (ii) Second group, fourth period. (iii) CaO+H2O →  Ca(OH)2