Question

plzz solve Q 8 in the following image

Answer 1

For vessel,
Heat energy needed = mcΔt
= 50x400x(30-5)
= 50x400x25
= 500000J  (i)

For water,
Energy needed = 250x4200x(30-5)
=250x4200x25
=26250000  (ii)

For ice,
Let the mass be m
Energy needed to melt = m x 336000
= 336000m  (iii)
Energy needed after melting = m x 4200x(5-0)
= m x 4200x5
= 21000m  (iv)

From (i), (ii), (iii) and (iv)
500000+26250000 = 336000m+21000m
26750000 = 357000m
m = 26750000/357000
m = 74.929
m = 74.93g

∴ Mass of ice needed = 74.93g