College Physics

100 grams of molten lead (600oC) is used to make musket balls. If the lead shot is allowed to cool to room temperature (21oC), what is the change in entropy (in J/K) of the lead? (For the specific heat of molten and solid lead use 1.29 J/g oC; the latent heat of fusion and the melting point of lead are 2.45 x 104 J/kg and 327oC.)

  1. 👍 0
  2. 👎 0
  3. 👁 678
  1. For each incremental heat loss dQ, there is an entropy loss of the lead that is equal to dQ/T, where T must be in Kelvin. Compute the total entropy loss in three steps:
    (1) liquid lead cooling from 873 to 600 C
    (2) molten lead turning to solid at a contant temperature of 600 K while the heat of fusion is transferred away, and
    (3) solid lead cooling from 600 K to 294 K.

    You are supposed to use the same specific heats for the liquid and solid lead in this case; this is an approximation. Call the specific heat of both C.

    Entropy loss is:
    (1) Integral of dQ/T from T = 873 to 600 = M C ln(873/600), where M is the mass and C is the specific heat,PLUS
    (2) Integral of dQ/T as the lead freezes, M*Qf/600, where Qf is the latent heat of fusion, PLUS
    (3) Integral of dQ/T from T=600 to T = 294 K, = M C ln(600/400)

    Now just add up the numbers. Use numeric values for M, Qf and C.

    1. 👍 0
    2. 👎 1
  2. Check your given specific heat of lead. Yours appears to be off by a factor of about ten. I get 0.127 J/g*K for the solid and 0.120 J/g*K for the liquid, from various web sites.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    Excess lead (II) nitrate solution is added to 1.30 g of zinc powder and the mixture is stirred. When the reaction is finished the lead formed is filtered, dried and weighted. It has a mass of 3.31 g. What is the percentage yield

    asked by chem_cg on July 11, 2017
  2. science

    A 15.0 gram lead ball at 25.0°C was heated with 40.5 joules of heat. Given the specific heat of lead is 0.128 J/g∙°C, what is the final temperature of the lead?

    asked by Suizaranne on February 6, 2013

    The specific heat capacity (cp) of lead is 0.13 J/g °C. How much heat (in J) is required to raise the temperature of 15 grams of lead from 22 °C to 37 °C? a. 2.0 b. -0.13 c. 0.13 d. 29

    asked by GRACE on May 9, 2010
  4. chemistry

    When aqueous solutions of sodium sulfate and lead (II) nitrate are mixed lead sulfate precipitates out of soultion. Calculate the mass of lead (II) sulfate that should form when 1.25 L of 0.0500 M Pb(NO3)2 and 2.00 L of 0.0250 M

    asked by Bella on February 21, 2012
  1. Physics

    A lead bullet of mass 50 grams is fired with a velocity of 200m/s into a lead block of mass 950 grams. Given that the lead block can move freely, calculate the kinetic energy after impact and the loss of energy.

    asked by Williams on May 30, 2015
  2. chemistry

    In the 1970s, when lead was widely used in "ethyl" gasoline, the blood level of the average American contained 0.25 ppm lead. The danger level of lead poisoning is 0.80 ppm. (a) What percent of the average person was lead? (b) How

    asked by Hannah on March 19, 2012
  3. geometry

    Four metal balls fit snugly inside a cylindrical can. A geometry student claims that two extra balls of the same size can be put into the can, provided all six balls can be melted down and the molten liquid poured into the can. Is

    asked by Piggy on March 2, 2012
  4. chemistry

    Lead is often found in Earth's crust as several lead compounds. Calculate the mass in kilograms of the amount of each of the following lead compounds that contains 4500kg of lead. 1)PbCO3 (cerussite) 2) PbSO4(anglesite)

    asked by rachel on October 26, 2010
  1. Physics

    How much energy is needed to melt 0.225 kg of lead so that it can be used to make a lead sinker for fishing? The sample has an initial temperature of 27.3 degrees celsius and is poured in the mold immediately after it has melted.

    asked by Kim on March 30, 2010
  2. Chemistry

    A lead atom has a mass of 3.40×10−22 g. How many lead atoms are in a cube of lead that has a volume of 1.40 cm^3 if the density of lead is 11.3 g/cm^3?

    asked by Vy on March 7, 2011
  3. Reading

    45. 'lead (led). n 1. Position at the front 2. initiative 3. One that leads. 4. Indication or clue. 5. A principal role in a dramatic production ‘lead (led) v. 1 to guide on a way by going in advance. 2. To direct on a course.

    asked by BARNETTA on August 15, 2015
  4. Physics

    You have a 2.00 kg block of lead. Lead melts at 327.5°C. CPb = 130.0 , and Hf for lead is 2.04 × 104 J/kg. Say you start at room temperature (25.0°C). How much heat must you transfer to melt all the lead?

    asked by Pat on March 18, 2012

You can view more similar questions or ask a new question.