How Much Energy Does Dropping a Hot Copper Cylinder into Water Transfer?

In summary, the final temperature of the system is 100°C and the total energy transferred to the water as heat is 94.031 kJ.
  • #1
sciontc03
10
0
A 125 g copper bowl contains 235 g of water, both at 20.0°C. A very hot 300 g copper cylinder is dropped into the water, causing the water to boil, with 5.05 g being converted to steam. The final temperature of the system is 100°C. Neglect energy transfers with the environment.
How much energy is transferred to the water as heat?

I found the heat for the steam, bowl, water, and part of the cylinder except for the initial temp of the cylinder. I don't know where to go from there.
Qs= 11.39kJ
Qw=78.772kJ
Qb=3.86kJ
Please help.
 
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  • #2
The total heat transferred to the water is the sum of the heats of the steam, bowl and part of the cylinder. This is equal to 94.031 kJ.
 
  • #3


Based on the given information, we can calculate the initial temperature of the copper cylinder by using the conservation of energy equation: Qs + Qw + Qb = Qc, where Qc is the heat transferred to the copper cylinder.

Qc = m x c x ΔT (mass x specific heat capacity x change in temperature)

Qc = (300g)(0.385 J/g°C)(Tf - Ti)

Qc = 115.5Tf - 115.5Ti

We know that the final temperature (Tf) is 100°C, and the initial temperature (Ti) is unknown. We also know that the heat for the steam (Qs) is 11.39 kJ, the heat for the water (Qw) is 78.772 kJ, and the heat for the bowl (Qb) is 3.86 kJ.

Substituting these values into the conservation of energy equation, we can solve for the initial temperature of the copper cylinder:

11.39 kJ + 78.772 kJ + 3.86 kJ + 115.5Tf - 115.5Ti = 0

115.5Tf - 115.5Ti = -94.022 kJ

Since we know the final temperature (Tf) is 100°C, we can solve for the initial temperature (Ti):

115.5(100) - 115.5Ti = -94.022 kJ

11550 - 115.5Ti = -94.022 kJ

115.5Ti = 11644.022 kJ

Ti = 100.7°C

Therefore, the initial temperature of the copper cylinder was 100.7°C before it was dropped into the water.

To calculate the total energy transferred to the water as heat, we can use the specific heat capacity of water (4.184 J/g°C) and the change in temperature (80°C):

Qw = m x c x ΔT

Qw = (235g)(4.184 J/g°C)(80°C)

Qw = 7817.04 J = 7.817 kJ

So, the total energy transferred to the water as heat is 7.817 kJ.
 

Related to How Much Energy Does Dropping a Hot Copper Cylinder into Water Transfer?

1. How does energy transfer occur?

Energy transfer occurs when energy is transferred from one object to another through different mechanisms, such as heat, light, or motion. This transfer can happen through direct contact or through waves and particles.

2. What is the law of conservation of energy?

The law of conservation of energy states that energy cannot be created or destroyed, but can only be transferred or converted from one form to another. This means that the total amount of energy in a closed system remains constant.

3. What are the different types of energy transfer?

The different types of energy transfer include conduction, convection, radiation, and mechanical energy transfer. Conduction is the transfer of heat or electricity through direct contact, convection is the transfer of heat through the movement of fluids, radiation is the transfer of energy through electromagnetic waves, and mechanical energy transfer is the transfer of energy through movement or force.

4. How do energy transfers affect the environment?

Energy transfers can have both positive and negative effects on the environment. For example, the emission of greenhouse gases from energy production can contribute to global warming, while the use of renewable energy sources can help reduce pollution and lessen the impact on the environment.

5. How can we increase the efficiency of energy transfer?

There are several ways to increase the efficiency of energy transfer, such as using more efficient technologies, reducing energy waste, and implementing conservation measures. By using energy-efficient devices and practices, we can minimize the amount of energy lost during transfer and make the best use of the energy we have.

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