Flag Thermal Physics> amount of water availabe by melting ice b...
question mark

A person is stuck in Antarctica in a ship wreck. He doesnt have any drinking water available.
He finds an ethylene (CH2=CH2) cylinder containing 4.2 g of ethylene. He decides to burn this
ethylene to melt 1kg of ice at 10oC.
When a mole of ethylene is combusted it releases 340 kcal of
energy. Assuming, no heat is lost to the environment, the amount of water available for drinking is...
(in ml).

Sourav Goyal , 13 Years ago
Grade 10
anser 1 Answers
Askiitians Tutor Team

Last Activity: 5 Months ago

To determine how much water can be produced from burning ethylene, we first need to calculate the energy released from the combustion of the ethylene and then see how much ice can be melted with that energy. Let's break this down step by step.

Understanding Ethylene Combustion

Ethylene (C2H4) combusts in the presence of oxygen to produce carbon dioxide and water. The combustion reaction can be summarized as follows:

C2H4 + 3 O2 → 2 CO2 + 2 H2O

From the problem, we know that burning one mole of ethylene releases 340 kcal of energy. First, we need to find out how many moles of ethylene are in the 4.2 g cylinder.

Calculating Moles of Ethylene

The molar mass of ethylene (C2H4) is calculated as follows:

  • Carbon (C): 12.01 g/mol × 2 = 24.02 g/mol
  • Hydrogen (H): 1.008 g/mol × 4 = 4.032 g/mol
  • Total molar mass = 24.02 g/mol + 4.032 g/mol = 28.052 g/mol

Now, we can calculate the number of moles of ethylene in 4.2 g:

Number of moles = mass (g) / molar mass (g/mol)

Number of moles = 4.2 g / 28.052 g/mol ≈ 0.149 moles

Energy Released from Combustion

Next, we calculate the total energy released from burning 0.149 moles of ethylene:

Total energy = moles × energy per mole

Total energy = 0.149 moles × 340 kcal/mole ≈ 50.6 kcal

Melting Ice with the Released Energy

To melt ice, we need to know how much energy is required to convert ice at 0°C to water at 0°C. The latent heat of fusion for ice is approximately 80 kcal/kg. Therefore, to melt 1 kg of ice, we need:

Energy required = mass × latent heat of fusion

Energy required = 1 kg × 80 kcal/kg = 80 kcal

Comparing Energy Values

Now, we compare the energy released from the combustion of ethylene (50.6 kcal) with the energy required to melt 1 kg of ice (80 kcal). Since 50.6 kcal is less than 80 kcal, we cannot melt the entire 1 kg of ice. Instead, we can determine how much ice can be melted with the available energy.

To find out how much ice can be melted with 50.6 kcal:

Mass of ice melted = energy available / latent heat of fusion

Mass of ice melted = 50.6 kcal / 80 kcal/kg ≈ 0.6325 kg

Converting Mass of Water to Volume

Since the density of water is approximately 1 g/ml, we can convert the mass of water melted into volume:

Volume of water (ml) = mass of water (g)

Given that 0.6325 kg of ice melts into 0.6325 kg of water, we convert this to grams:

0.6325 kg = 632.5 g

Thus, the volume of water available for drinking is:

Volume = 632.5 ml

Final Result

In summary, by burning the ethylene, the person can produce approximately 632.5 ml of water from melting ice. This calculation highlights the importance of energy conversion and the practical applications of chemistry in survival situations.

star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments