Nov 2008 questions 15,20,29
help!..
15) C...if it absorbs 10 from 1000cm^3 then it would absorb twice as much of heat from 500cm^3 since volume is halved!
20)HCL + BaNO3-->HNO3+BACL ....therefore the acidic nitric acid decrease the pH and since barium reacts with chlorine,therfore no precipitate
29)metals donot have 6 in their outa shell and always form ionic compounds thus B
for 15 the answer is A not C since the reaction is enothermic !
buh i still dont get it how will the solution absorb more heat if it has been halved . This is what i made out of it: since one of th rectants is being halved you wud need only half the energy .
It is just like physics. It takes double the amount of heat energy to increase the temperature of 1000 cm
3 of water by 1 degree celsius, than to increase the temperature of 500, by 1 degree. Thus, if there is half the volume of water, and the same amount of heat, the temperature change will be double. Take an example of sharing money (assume, it is heat) between 10 children (assume its 1000 cm
3 of water). If we half the number of children to 5 (volume decreased to 500), the amount of money each will get, will double (temperature increases).