Energy problem - ice melted by burning ethanol

In summary, we are given the question of how many grams of ice at 0°C can be melted by the heat produced when 10.0g of ethanol is burned. We are provided with the combustion reaction and the heat of formation, and we need to find the mass of ice melted using the equation m(ice) = q/L_f * m(ethanol). The correct answer is 802g.
  • #1
philtered
8
0

Homework Statement


How many grams of ice at 0°C could be melted by the heat produced when 10.0g of ethanol is burned?

Homework Equations


So I wrote out the combustion reaction:
C2H5OH +3O2 ---> 2CO2 + 3H2O

The Attempt at a Solution


First I though I had to find heat of formation for that reaction, which I found to be -1235.6kJ (So this would be the heat given off when ethanol is burned correct?)
Hf=products-reactants
Hf=[-393.6(2)+-242(3)]-[-277.6+0]
Hf=-1235.6kJ

I wasn't sure if I had to use that number or if I had to just pull the Hf number off my chart for ethanol (-277.6kJ)

I have the answer given to me, but I'm stuck at converting my kJ to g of water. (Answer is 802g)

Tried: 1235.6kJ[1mol/6.03kJ][18.02g/1mol]
 
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  • #2
You need to constants. The latent heat of fusion of ice (let us denote it by [tex]L_{f}[/tex]) and the energy released by burning a unit mass of ethanol (let us denote it by [tex]q[/tex]). Then, you simply have:

Heat needed to melt mass [tex]m(\texrm{ice})[/tex] = [tex] L_{f} \cdot m(\textrm{ice})[/tex]

Heat released by burning mass [tex]m(\textrm{ethanol})[/tex] = [tex]q \cdot m(\textrm{ethanol})[/tex]

These are equal, so, you have an equation for [tex]m(\textrm{ice})[/tex]:


[tex]
m(\textrm{ice}) = \frac{q}{L_{f}} m(\textrm{ethanol})
[/tex]
 
  • #3
Thanks for the help. It worked out with that. Also the q value I was using was wrong, had forgot to take into account the 10g of ethanol being burned.
 
  • #4
cool. am i right to assume you're a chem student?
 
  • #5
Yeah I am. Right now just the high school course, next year I'm doing Physics with a minor in Chem
 

What is the "energy problem"?

The "energy problem" refers to the global issue of balancing the demand for energy with the need for sustainable and renewable sources of energy. It also includes the negative impacts of using non-renewable energy sources, such as fossil fuels, on the environment and human health.

How does burning ethanol contribute to the melting of ice?

When ethanol is burned, it releases carbon dioxide into the atmosphere. This carbon dioxide contributes to the greenhouse effect, trapping heat and causing global temperatures to rise. As a result, ice caps and glaciers melt at a faster rate, leading to rising sea levels and other environmental consequences.

What is the relationship between melting ice and sea level rise?

As ice melts, the water from the melted ice flows into the oceans, causing sea levels to rise. This can have significant consequences for coastal communities and ecosystems, as well as exacerbate the impacts of natural disasters like hurricanes and storm surges.

What are the potential solutions to the energy problem?

There are many potential solutions to the energy problem, including increasing the use of renewable energy sources like wind and solar power, improving energy efficiency, and implementing sustainable practices in industries such as transportation and agriculture. It will also require a global effort to reduce our dependence on fossil fuels and transition to cleaner and more sustainable forms of energy.

How can individuals contribute to solving the energy problem?

Individuals can play a crucial role in solving the energy problem by making small but impactful changes in their daily lives. This includes reducing energy consumption, using public transportation or electric vehicles, supporting and investing in renewable energy, and advocating for sustainable policies and practices. Every small action adds up to make a significant difference in combating the energy problem.

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