6.11% w/v of Cu2+ implies that 6.11 g of Cu2+ is present in 100 ml of the solution
therefore, 250 ml of the solution would have: 250 ml * 6.11 g/100 ml = 15.275 g
# moles of Cu2+ = 15.275 g/63.546 g mole-1 = 0.2404 moles
1 mole of CuCl2 contain 1 mole of Cu2+ ion
Hence, 0.2404 moles of Cu2+ would correspond to 0.2404 moles of CuCl2
Molar mass of CuCl2 = 134.452 g/mole
The mass of CuCl2 required = 0.2404 moles * 134.452 g/mole = 32.32 grams
Proton, the gold foil experiment indicated that the nucleus has a positive charge.
Answer:
It works by separating the fuel from the oxygen. The oxygen comes from the air. It is the same oxygen we breathe. Since the oxygen has to be in contact with the fuel, if you can coat the fuel with something that keeps the oxygen away, the fire will go out which is what the fire extinguisher does.
When water at 50 C is added to ice at -12 C, heat is transferred from hot water to ice.
- Heat given out by water = Heat absorbed by ice
Calculating the heat released by hot water:
ΔT

Calculating heat absorbed by 16 g of ice: Ice at
is converted to ice at
and then ice at
to water at 
ΔT + 
+ 
q = 405.12 J +5336.8 J =5741.92 J
- Heat given out by water = Heat absorbed by ice
-(
m = 27.4 g
Therefore, 27.4 g water at
must be added to 16 g of ice at
to convert to liquid water at 