Question

A 21.6-kg cube made from aluminum is at its melting temperature of 660℃. If you were to add 8000 kJ worth of energy as heat, what percent of the block melts? You might need the following: α = 23.0 ✕ 10-6 K-1 , β = 69.0 ✕ 10-6 K-1 , c = 900 J/kgK, LF = 3.98 ✕ 105 J/kg

Answer 1

The percentage of block melts is 93.1 %

Step-by-step explanation:

Let the block melted be m₁

Given: LF = 3.98 * 10⁵ J/kg

Amount of heat added , Q = 8000 KJ = 8×10⁶ J

Using:

Q = m₁×LF

8×10⁶ = m₁ * 3.98 * 10⁵

m₁ = 20.1 kg

So, the percentage of block melts , % = m₁/m * 100

% = 20.1 /21.6 * 100 = 93.1 %

The percentage of block melts is 93.1 %