Acopper block with a mass of 300 grams is cooled to 77k by being immersed in liquid nitrogen. the block is then placed in a styrofoam cup containing some water that is initially at +50.0°c. assume no heat is transferred to the cup or the surroundings. the specific heat of liquid water is 4186 j/(kg °c), of solid water is 2060 j/(kg °c), and of copper is 385 j/(kg °c). the latent heat of fusion of water is 3.35 x 105 j/kg. when the system comes to equilibrium, the temperature is 0°c.(a) calculate the maximum possible mass of water that could be in the cup. (g)(b) calculate the minimum possible mass of water that could be in the cup. (g)

Explanation:

mass of copper block  = 0.3 kg at 77 K or -196 °C

Let mass of water taken be m ( maximum) , in this case we will have mixture of water and copper block at 0°C finally.

Heat gained by copper block

= msΔt

.3 x 196 x 385 J

heat lost by water to lower its temp fro 50°C to 0°C

= m x 4186 x 50

Heat lost = heat gained

m x 4186 x 50 = .3 x 196 x 385

m = 108.16 gm

Let mass of water taken be m ( minimum ) , in this case we will have mixture of ice  and copper block at 0°C finally.

heat lost by water to lower its temp fro 50°C to 0°C

= m x 4186 x 50

heat lost by water to lower its temp from 0°C to 0°C ice

= m x latent heat of fusion

m x 3.35 x 10⁵

Total heat lost

= m x 3.35 x 10⁵ + m x 4186 x 50

= 544300 m

Heat gained by copper block

= msΔt

.3 x 196 x 385 J

Heat lost = heat gained

544300 m = .3 x 196 x 385 J

m = 41.6 gm

divide the right side by the left side

0.024÷1.2=0.02 for example

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz