chem oct/nov 2010 p11 help

[robinho10]

5.(working plz)
9.(working plz)

 

[CommonSense]

The mass of nickel is 20% * 10 = 2g
The Ar of nickel is 58.7 so the number of moles is 2/58.7
Multiply the number of moles by Avogadro's constant ie 6.02E23 (which is the number of particles per mole) and u will get the answer A

Energy = mass * specific heat capacity * temperature change = 200 * 4.2 * 48
But this is only 45% of the energy released so divide the answer by 0.45 to get the total energy released
Finally, divide the total energy by the mass which is 1.6g and u will get the answer B

 

[robinho10]

The mass of nickel is 20% * 10 = 2g
The Ar of nickel is 58.7 so the number of moles is 2/58.7
Multiply the number of moles by Avogadro's constant ie 6.02E23 (which is the number of particles per mole) and u will get the answer A

Energy = mass * specific heat capacity * temperature change = 200 * 4.2 * 48
But this is only 45% of the energy released so divide the answer by 0.45 to get the total energy released
Finally, divide the total energy by the mass which is 1.6g and u will get the answer B

thnxxx aloooot !

 

[CommonSense]

U r most welcome

 

[lychee26]

nov 10 paper 11 was HARD.