A heat transfer of 8.0×105 J is required to convert a block of ice at -15 ∘C to water at 15 ∘C. How to find the mass?

Specific heat capacity for water, c(water) = 4.184 J/(mol °C)
Specific heat capacity for ice, c(ice) = 2.010 J/(mol °C)
Specific latent heat of fusion for water at 0°C, Lf = 334 J/g

Let m g be the mass of the block of ice.

Energy required for raising temperature = m c ΔT
Energy required for melting = m Lf

Energy required to convert the block of ice from -15°C to 0°C
= m × 2.010 × [0 - (-15)] (J)
= 30.15m J

Energy required to convert the block of ice to water at 0°C
= m × 334 J
= 334m J

Energy required to convert the water from o°C to 15°C
= m × 4.184 × (15 - 0) J
= 62.76m J

Total energy required = 8 × 10⁵ J
30.15m + 334m + 62.76m = 8 × 10⁵
426.91m = 8 × 10⁵
m = 1870

Mass of the block of ice = 1870 g

E = mi*(ci*ΔT1+cw*ΔT2+333)
mi = 8*10^5/(2.19*15+4.186*15+333) = 1866.4 grams