std 8 science ch 4 swadhyay pothi , dhoran 8 vigyan swadhyay pothi , dhoran 8 swadhyay pothi vigyan

The enthalpy change of the reaction C_3H_8(g)+H_2(g) rarr C_2H_6(g)+CH_4(g) , at 25^@ , will be Given that: heat of combustion values under standard condition (The standard heat of formation of C_3H_8(g) is -103.8kJ/mol)

Out of 100 students, 15 passed in English, 12 passed in Mathmatics, 8 in Science, 6 in English and Mathematics, 7 in Mathematics and Science , 4 in English and Science, 4 in all the three. Find how many passed (i) in English and Mathematics but not in Science. (ii) in Mathematics and Science but not in English. (iii) in Mathematics only. (iv) in more than one subject only.

There are 8 math's books and 6 science books in a almirah. In how many wayscan 4 books of each subject be selected?

Ethanol can undergo decompostion to form two sets of products. If the molar ratio of C_(4)H_(4) "to" CH_(3)CHO is 8:1 in a set of product gases, then the energy involved in the decomposition of 1 mole of ethanol is:

Acetic acid, (CH_(3)COOH), has a pK_(a) of 4.8 . Ethanol, (CH_(3)CH_(2)OH) has a pK_(a) of 16.0 . What are the major species present, when acetic and ethanol are added to water and th e pH is odjusted to 7.0 ?

Both conc. Being 1 M, the factor by which the percent hydrolysis of CH_3COO^- is greater in CH_3COONH_4 than in CH_3COONa is : [K_a(CH_3COOH)=K_b(NH_4OH)=1.8xx10^(-5)]