Answer:
2.45 × 10⁴ J
Explanation:
We can calculate the heat necessary to raise the temperature of 40.0 g of aluminum from 20.0 °C to 700.0 °C using the following expression.
Q = c × m × ΔT
where,
Q = c × m × ΔT
Q = (0.900 J/g.°C) × 40.0 g × (700.0 °C - 20.0 °C)
Q = 2.45 × 10⁴ J
Answer:
We need 40.4 kJ to raise the temperature to 700.0 °C
Explanation:
Step 1: Data given
Mass of aluminium = 40.0 grams
Specific heat of aluminium = 0.900 J/g°C
The initial temperature = 20.0 °C
The final temperature = 700.0 °C
The melting point of aluminium = 660.3 °C
Step 2: Calculate heat needed to raise aluminium from 20.0 °C to 660.3 °C
Q = m*C*ΔT
⇒with Q = the heat needed = TO BE DETERMINED
⇒with m =the mass of aluminium = 40.0 grams
⇒with c = the specific heat of aluminium = 0.90 J/g°C
⇒with ΔT = the change of temperature = T2 - T1 = 660.3 - 20.0 = 640.3 °C
Q = 40.0 * 0.900 * 640.3
Q = 23050.8 J
Step 3: Calculate heat need to melt aluminium
Q = m*ΔHfusion
Q = 40.0 g*398 J/g
Q = 15920 J
Step 4: Calculate heat needed to raise aluminium from 660.3 to 700.0°C
Q = m*C*ΔT
⇒with Q = the heat needed = TO BE DETERMINED
⇒with m =the mass of aluminium = 40.0 grams
⇒with c = the specific heat of aluminium = 0.90 J/g°C
⇒with ΔT = the change of temperature = T2 - T1 = 700 - 660.3 = 39.7 °C
Q = 40.0 * 0.90 * 39.7
Q = 1429.2 J
Step 5: Calculate the total heat needed
Q = 23050.8 + 15920 + 1429.2
Q = 40400 J = 40.4 kJ
We need 40.4 kJ to raise the temperature to 700.0 °C
