All categories

2 years ago

What is the change in entropy of the lead when 2.0 kg of molten lead at its melting point temperature solidifies.

1 answer:

7 0

Answer: The change in entropy of the lead when 2.0 kg of molten lead at its melting point temperature solidifies is 20 cal/K.

Explanation:

$Pb(l)\rightleftharpoons Pb(s)$

$\Delta S=\frac{q}{T}$

${\text{Change in entropy}}=\frac{heat}{Temperature}$

T is the temperature at which the process is carried out, here the temperature is constant, 327.5°C = $(273+327.5)K=600.5K$ ,because only phase change occurs.

q = heat given in the process = $m\times L_f$

m = mass of lead = 2.0 kg

$L_f$ = latent heat of fusion of lead = 5.9 kcal/kg

$\Delta S=\frac{2kg\times 5.9kcal/kg}{600.5K}$

$\Delta S=0.02 kcal/K=20cal/K$

Thus the change in entropy of the lead when 2.0 kg of molten lead at its melting point temperature solidifies is 20 cal/K.

You might be interested in

___ is anything that has mass and volume<br>Pls help

aliina [53]

Matter is anything that has mass and volume

8 0

3 years ago

Read 2 more answers

Naturally occurring zirconium exists are five isotopes. axe with a mass of 89.905 u(51.45%); Zr with a mass of 90.906 u (11.22%)

Anton [14]

Isotope 1: 89.905 * 51.45 = 4625.61225 / 100 = 46.2561225
Isotope 2: 90.906 * 11.22 = 1019.96532 / 100 = 10.1996532
Isotope 3: 91.905 * 17.15 = 1576.17175 / 100 = 15.7617075
Isotope 4: 93.906 * 17.38 = 1632.08628 / 100 = 16.3208628
Isotope 5: 95.908 * 2.08 = 268.5424 / 100 = 2.685424

46.2561225 + 10.1996532 + 15.7617075 + 16.3208628 + 2.685424 = 91.22377
actual mass Zr = about 91.22

8 0

3 years ago

Each of the following values was read on an instrument of measuring device. In each case the last digit was estimated. Tell what

Drupady [299]

Answer:

Explanation:

6 0

2 years ago

Given the partial equation:

Nikolay [14]

Answer : The balanced chemical equation in acidic medium will be,

$IO_3^-(aq)+2Sn^{2+}(aq)+6H^+(aq)\rightarrow I^-(aq)+2Sn^{4+}(aq)+3H_2O(l)$

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

Rules for the balanced chemical equation in acidic solution are :

First we have to write into the two half-reactions.

Now balance the main atoms in the reaction.

Now balance the hydrogen and oxygen atoms on both the sides of the reaction.

If the oxygen atoms are not balanced on both the sides then adding water molecules at that side where the less number of oxygen are present.

If the hydrogen atoms are not balanced on both the sides then adding hydrogen ion $(H^+)$ at that side where the less number of hydrogen are present.

Now balance the charge.

The given chemical reaction is,

$IO_3^-(aq)+Sn^{2+}(aq)\rightarrow I^-(aq)+Sn^{4+}(aq)$

The oxidation-reduction half reaction will be :

Oxidation : $Sn^{2+}\rightarrow Sn^{4+}$

Reduction : $IO_3^-\rightarrow I^-$

First balance the main element in the reaction.

Oxidation : $Sn^{2+}\rightarrow Sn^{4+}$

Reduction : $IO_3^-\rightarrow I^-$

Now balance oxygen atom on both side.

Oxidation : $Sn^{2+}\rightarrow Sn^{4+}$

Reduction : $IO_3^-\rightarrow I^-+3H_2O$

Now balance hydrogen atom on both side.

Oxidation : $Sn^{2+}\rightarrow Sn^{4+}$

Reduction : $IO_3^-+6H^+\rightarrow I^-+3H_2O$

Now balance the charge.

Oxidation : $Sn^{2+}\rightarrow Sn^{4+}+2e^-$

Reduction : $IO_3^-+6H^++4e^-\rightarrow I^-+3H_2O$

The charges are not balanced on both side of the reaction. Thus, we are multiplying oxidation reaction by 2 and the adding both equation, we get the balanced redox reaction.

Oxidation : $2Sn^{2+}\rightarrow 2Sn^{4+}+4e^-$

Reduction : $IO_3^-+6H^++4e^-\rightarrow I^-+3H_2O$

The balanced chemical equation in acidic medium will be,

$IO_3^-(aq)+2Sn^{2+}(aq)+6H^+(aq)\rightarrow I^-(aq)+2Sn^{4+}(aq)+3H_2O(l)$

5 0

3 years ago

1.0 gallon to mm<br>N.B 1 gallon=3.8L

I am Lyosha [343]

Answer:

Gallon (US) to Milliliter Conversion Table

Gallon (US) [gal (US)] Milliliter [mL]

1 gal (US) 3785.411784 mL

2 gal (US) 7570.823568 mL

3 gal (US) 11356.235352 mL

5 gal (US) 18927.05892 mL

4 0

2 years ago