Polonium is a rare element with 33 radioisotopes. The most common one, 210Po, has 82 protons and 128 neutrons. When 210Po decays, it emits an alpha particle, which is a helium nucleus (2 protons and 2 neutrons). 210Po decay is tricky to detect because alpha particles do not carry very much energy compared to other forms of radiation. For example, they can be stopped by a single sheet of paper or a few inches of air. That is one reason why authorities failed to discover toxic amounts of 210Po in the body of former KGB agent Alexander Litvinenko until after he died suddenly and mysteriously in 2006. What element does an atom of 210Po change into after it emits an alpha particle?

Answer:

Here's how I would explain it.

Explanation:

Think of it this way.

When you mix solutions of silver nitrate and sodium chloride, you get an immediate precipitate of silver chloride. The equation is

Ag⁺(aq) + Cl⁻(aq) ⟶ AgCl(s)

Now, take some AgCl and stir it vigorously with water.

You won't see much happening, because the AgCl is has such a low solubility. Not much of it will go into solution. And yet, a small amount of it does dissolve until the solution is saturated.

The concentration of AgCl in the saturated solution is

about 0.000 01 mol·L⁻¹.

I hope you will agree that this is a dilute solution even though it is saturated with AgCl.

Answer:

marie curie

Explanation:

It is Marie Curie who is a famous scientist for her research on radioactivity...

The density of NO2 in a 4.50 L tank at 760.0 torr and 25.0 °C is approximately 1.64 g/L.

To calculate the density of NO2 in a 4.50 L tank at 760.0 torr and 25.0 °C, we can use the ideal gas law and the molar mass of NO2. The ideal gas law equation is PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature. Rearranging the equation, we have n = PV/RT. First, we need to calculate the number of moles of NO2 in the tank. We can calculate this by dividing the pressure in torr by the ideal gas constant (0.08206 L atm/K mol), multiplied by the temperature in Kelvin. Then we can divide the calculated number of moles by the volume of the tank to get the molar concentration. Finally, we can divide the mass of NO2 by the volume of the tank to get the density. Using this method, the density of NO2 in the 4.50 L tank at 760.0 torr and 25.0 °C is approximately 1.64 g/L (Option A).

Answer:

metals as they have free electrons

Answer:

The answer is metals

Explanation:

Metals, for example mercury (Hg), iron (Fe) and copper (Cu), have metallic bonds. In this kind of bond the electrons are deslocalized. That means that electrons moves from one atom to another, by forming a "sea of electrons". Several properties of metals, such as electrical and thermal conductivity, are explained by this model of chemical bond.

Answer:

At-207 (meaning At with the number on the top left being 207 and the number at the bottom left being 85.

Explanation:

The sum of the mass numbers has to equal on both sides, so we need 211 = 4+a

a=207

The sum of the atomic numbers as to equal on both sides, so 87=2+b

b=85

The element is determined by the mass number.

Answer:

[tex]\boxed{\text{B.}}[/tex]

Explanation:

B.

[tex]\rm C$_7$H_{16}$ + 11O$_2$ $\longrightarrow \,$ 7CO$_2$ + 8H$_2$O[/tex]

BALANCED. 7C, 16H, and 22O on each side of equation.

A.

[tex]\rm C$_7$H$_{16}$ + 5O$_2$ $\longrightarrow \,\rm 6CO$_2$ + 4H$_2$O[/tex]

NOT BALANCED. 7C on left and 6C on right.

C.

[tex]\rm C$_7$H$_{16}$ + 14O$_2$ $\longrightarrow \,$ 7CO$_2$ + 5H$_2$O[/tex]

NOT BALANCED. 16H on left and 10H on right.

D.

[tex]\rm C$_7$H$_{16}$ + 22O$_2$ $\longrightarrow \, $ 14CO$_2$ + 16H$_2$O[/tex]

NOT BALANCED. 7C on left and 14C on right.

Answer:

33 degrees

Explanation:

The critical angle for a light ray moving from a denser medium with refractive index [tex]n_1[/tex] to a second medium with refractive index [tex]n_2[/tex] is given by

[tex]\theta_c = sin^{-1} (\frac{n_2}{n_1})[/tex]

In this case, the critical angle occurs when light moves from diamond to water. The index of refraction of the two materials are:

[tex]n_d = 2.42[/tex] for diamond

[tex]n_w = 1.33[/tex] for water

So the critical angle is

[tex]\theta_c = sin^{-1} (\frac{1.33}{2.42})=sin^{-1}(0.550)=33.3^{\circ}[/tex]

Answer:The second law

Answer:

second

Explanation:

Answer:

C) 4.8 L NH₃.

Explanation:

N₂(g) + 3H₂(g) → 2NH₃(g),

It is clear that 1.0 moles of N₂ react with 3.0 moles of H₂ to produce 2.0 moles of NH₃.

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

1.0 mol of N₂ represents → 22.4 L.

??? mol of N₂ represents → 2.4 L.

∴ 2.4 L of N₂ represents = (1.0 mol)(2.4 L)/(22.4 L) = 0.1071 mol.

1.0 mol of N₂ produce → 2.0 mol of NH₃, from stichiometry.

0.1071 mol of N₂ produce → ??? mol of NH₃.

∴ The no. of moles of NH₃ = (2.0 mol)(0.1071 mol)/(1.0 mol) = 0.2142 mol.

1.0 mol of NH₃ represents → 22.4 L, at STP.

0.2142 mol of NH₃ represents → ??? L.

∴ The no. of liters of NH₃ will be produced = (0.2142 mol)(22.4 L)/(1.0 mol) = 4.789 L ≅ 4.8 L.

So, the right choice is: C) 4.8 L NH₃.

Final answer:

Using Avogadro's law and the stoichiometry of the chemical equation for the production of ammonia, 2.4L of nitrogen gas will produce 4.8L of ammonia gas at standard temperature and pressure (STP).

Explanation:

According to Avogadro's law, equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. Therefore, we can use the balanced chemical equation N2(g) + 3 H2(g) → 2 NH3(g) to determine the volume of ammonia produced by the reaction. The equation tells us that one volume of nitrogen reacts with three volumes of hydrogen to produce two volumes of ammonia. Since we are assuming standard temperature and pressure (STP), we can directly relate the volumes of gases involved in the reaction.

If 2.4L of N2 are reacted with an excess of hydrogen, according to the stoichiometry of the reaction, it would produce twice the volume of NH3 because for every one volume of N2, two volumes of NH3 are produced. Therefore, 2.4L of N2 would produce 4.8L of NH3. Accordingly, the correct answer is C) 4.8L NH3.

Answer:

Part A: 6HClO₄(aq) + Fe₂O₃(s) → 2Fe(ClO₄)₃(aq) + 3H₂O(l).

Part B: H₂SO₄(aq) + Sr(s) → SrSO₄(s) + H₂(g).

Part C: H₃PO₄(aq) + 3KOH(aq) → K₃PO₄(aq) + 3H₂O(l).

Explanation:

Part A: complete HClO₄(aq) + Fe₂O₃(s)→ Express your answer as a balanced chemical equation. Identify all of the phases in your answer.

6HClO₄(aq) + Fe₂O₃(s) → 2Fe(ClO₄)₃(aq) + 3H₂O(l).

It is clear that 6 mol of HClO₄ (in aqueous phase) react with 1 mol of Fe₂O₃ (in solid phase) to produce 2 mol of Fe(ClO₄)₃ (in aqueous phase) and 3 mol of H₂O (in liquid phase).

Part B: H₂SO₄(aq) + Sr(s) → Express your answer as a balanced chemical equation. Identify all of the phases in your answer.

H₂SO₄(aq) + Sr(s) → SrSO₄(s) + H₂(g).

It is clear that 1 mol of H₂SO₄ (in aqueous phase) reacts with 1 mol of Sr (in solid phase) to produce 1 mol of SrSO₄ (in solid phase) and 1 mol of H₂ (in gas phase).

Part C: H₃PO₄(aq) + KOH(aq) → Express your answer as a balanced chemical equation.

H₃PO₄(aq) + 3KOH(aq) → K₃PO₄(aq) + 3H₂O(l).

It is clear that 1 mol of H₃PO₄ (in aqueous phase) react with 3 mol of KOH (in aqueous phase) to produce 1 mol of K₃PO₄ (in aqueous phase) and 3 mol of H₂O (in liquid phase).

Answer:

as the world is changing we change also

Explanation:

We must always check and recheck are a hypothesis

Answer:

Explanation:

Because sometimes in the details of an experiment there are details hidden away that no one has thought to exploit.

I like to use Cancer as an example. Most cancers have drugs associated with them that are actually poisons (although  scientists are getting much, much better in reducing side effects).

But the main purpose until recently is an example of survival of the fittest. Think Darwin.  The drug kills off the cancer cells that are most easily killed off. That leaves the slower growing more deadly forms of the cancer behind and they finish the job, because there is nothing to control them, nor is anything competing with them.

Without finding this out, biologists would be at a loss of where to turn. Oncologists repeat the same treatment hundreds of times until the have a feel for how the cancer works. Then they are better equipped to tackle the problem a new.

Answer:

[tex]p = \boxed{\text{593 torr}}[/tex]

Explanation:

For this question, we must use Dalton's Law of Partial Pressures:

The partial pressure of a gas in a mixture of gases equals its mole fraction times the total pressure:

[tex]p = \chi p_{\text{tot}}[/tex]

Data:

χ = 0.7808

[tex]p_{\text{tot}} = \text{ 760 torr}[/tex]

Calculation:

[tex]p = 0.7808 \times \text{ 760 torr}\\\\p= \boxed{\textbf{593 torr}}[/tex]

The partial pressure of nitrogen in the air, when the atmospheric pressure is 760 torr, is 593.4 torr. This is calculated using the given formula and the mole fraction of nitrogen.

The mole fraction of nitrogen (N₂) in the air is 0.7808 or 78.08%. This means that 78.08% of the molecules in the air are nitrogen. When talking about the partial pressure of gases, it means the contribution of that gas to the total pressure of the mixture. The partial pressure of any gas can be calculated using the formula P = (Patm) X (percent content in mixture). In this case, the atmospheric pressure (Patm) is 760 mm Hg, or torr. To find the partial pressure of nitrogen (N₂), multiply the atmospheric pressure by the mole fraction of nitrogen. So, Pₙ₂ = (760 torr) X (0.7808) = 593.4 torr. Therefore, when the atmospheric pressure is 760 torr, the partial pressure of nitrogen in the air is 593.4 torr.

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Answer:

Kelvin

Explanation:

Answer:

[tex]\boxed{\text{112 K}}[/tex]

Explanation:

A) Know

p₁ = Initial pressure;          p₂ = final pressure

V₁ =Initial volume;             V₂ = final pressure

T₁ = Initial temperature

B) Find

T₂ = final temperature

C) Strategy

Use the Combined Gas Laws Equation:

[tex]\dfrac{p_{1}V_{1}}{T_{1}} = \dfrac{p_{2}V_{2}}{T_{2}}[/tex]

It contains symbols for all the knowns and the unknown.

D) Calculations

(i) Data:

p₁ = 3.5 atm; p₂ = 1.5 L

V₁ = 3.2 L;     V₂ = 2.6 L

T₁ = 323 K     T₂ = ?

(ii) Calculation

[tex]\dfrac{3.5\times3.2}{323} = \dfrac{1.5\times 2.6}{T_{2}}\\\\0.0347 = \dfrac{3.90}{T_{2}}\\\\T_{2} = \dfrac{3.90}{0.0347} = \boxed{\textbf{112 K}}[/tex]

Bubbling And Fizzing

Answer:

Signs of chemical reactions are, if gas or bubbles are present, if a color changes occurs, or if a precipitate is formed, that could indicate that a chemical reaction has occurred.

Explanation:

Answer:

3) ester

Explanation:

Esterification is the process in which alkanol and alkanoic acids reacts in the presence of a catalyst and heat. The product is usually an ester(alkanoate) and water.

For the reaction between ethanoic acid and 1-butanol, the product is butylethanoate and water as shown below:

               CH₃COOH + C₄H₈OH → CH₃COOC₄H₈ + H₂O

Answer:

The acid dissociation constant, _Ka__, is a quantitative measure of acid strength

Explanation:

Answer:

16.0%.

Explanation:

Volume percent of a substance is the ratio of the substance volume to the solution volume multiplied by 100.

V % of ethanol = (volume of ethanol / volume of the solution) x 100.

volume of ethanol = 90.0 mL, volume of the solution = 550.0 mL.

∴ V % of ethanol = (90.0 mL / 550.0 mL) x 100 = 16.36% ≅ 16.0%.

Answer:

Explanation:

1) Since the average kinetic energy of a gas is only dependent on its temperature, you conclude that, at the same temperature of 70°C, the average kinetic energy of He atoms is the same that the average kinetic energy of NH₃ molecules: 7.1 × 10⁻²¹ J / molecule.

2) Now, you can use the equation that relates the average kinetic energy with the mean-square speed:

Where:

You need to use the atomic mass of helium to find the mass (average) of one atom of helum:

        m = 4.003 g/ mol / (6.022 × 10²³ atoms/mol)

        m = 6.647 × 10⁻²⁴ g = 6.647 10 ⁻²⁷ kg / atom

3) Solve for v², substitute, and compute:

Note: since He is a monoatomic molecule, kg/atom = kg/molecule.

            = 2.14 × 10⁶ m²/s² ← answer

Answer:

[tex]\boxed{\text{[PCl$_{5}$] = 0.0077 mol/L; [PCl$_{3}$] = [Cl$_{2}$] = 0.117 mol/L}}[/tex]

Explanation:

The balanced equation is

PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)

You don't give the volume of the flask, so I assume it is 1 L.

We can set up an ICE table to organize our calculations.

[tex]\begin{array}{lccccc} & \text{PCl}_{5} & \rightleftharpoons & \text{PCl}_{3} & + & \text{Cl}_{2} \\\text{I/mol}\cdot\text{L}^{-1}: & 0.125 & & 0 & & 0 &\\\text{C/mol}\cdot\text{L}^{-1}: & -x & & +x & & +x &\\\text{E/mol}\cdot\text{L}^{-1}:& 0.125-x & & x & & x &\\\end{array}[/tex]

[tex]K_{\text{c}} = \dfrac{\text{[PCl$_3$][Cl$_2$]}}{\text{[PCl$_5$]}} = \dfrac{x^{2}}{0.125-x} = 1.80[/tex]

Check for negligibility

[tex]\dfrac{0.125}{1.80} = 0.0674 < 400.[/tex]

x is not negligible, so we must solve a quadratic.

[tex]x^{2} = 1.80(0.125 - x)\\x^{2} = 0.225 - 1.80x\\x^{2} + 1.80x - 0.225 = 0\\[/tex]

Solve for x.

x = 0.1173

[PCl₅] = 0.125 - x = 0.125 – 0.1173 = 0.0077 mol·L⁻¹

[PCl₃] = x = 0.117 mol·L⁻¹

 [Cl₂] = x = 0.117 mol·L⁻¹

[tex]\boxed{\textbf{[PCl$_{5}$] = 0.0077 mol/L; [PCl$_{3}$] = [Cl$_{2}$] = 0.117 mol/L}}[/tex]

Check:

[tex]\dfrac{0.117^{2}}{0.0077} = 1.80\\\\\dfrac{0.0138}{0.0077} = 1.79[/tex]

Close enough. It checks.

In a chemical reaction when the reactants split to form two or more products are called a decomposition reaction. It is generally a breakdown of the reactants to yield products.

The concentrations of [tex]\rm PCl_{5}[/tex]  is 0.0077 mol/L, [tex]\rm PCl_{3}[/tex] and [tex]\rm Cl_{2}[/tex]  is 0.177 mol/L.

The balanced equation given is:

[tex]\rm PCl_{5} (g) \rightleftharpoons \rm PCl_{3} (g) + Cl_{2} (g)[/tex]

See the ICE table for the equation in the attached image below.

According to the table:

[tex]Kc = \dfrac{[\rm PCl_{3}] [Cl_{2}]}{[\rm PCl_{5}]}[/tex]

[tex]1.80 =\dfrac { x^{2} }{0.125 - x}[/tex]

Check the value for the negligibility:

[tex]\dfrac{0.125 }{1.80} = 0.0674 < 400[/tex]

From above it can be stated that it is not negligible and will be solved by the quadratic equation:

[tex]\begin{aligned}x^{2} &= 1.80 (0.125 - x)\\\\x^{2} &= 0.225 - 1.80x\\\\0 &= x^{2} + 1.80 x - 0.225\end{aligned}[/tex]

Solving further for x:

x = 0.1173

For gases:

[tex]\begin{aligned} \rm [PCl_{5}] &= 0.125 - x \\\\\rm [PCl_{5}] &= 0.125 - 0.1173 \\\\&= 0.0077 \;\rm mol L^{-1}\end{aligned}[/tex]

And,

[tex]\begin{aligned} \rm [PCl_{3}] &= 0.117 \;\rm mol L^{-1}\\\\\rm [Cl_{2}] &= 0.117 \;\rm mol L^{-1} \end{aligned}[/tex]

Therefore, the concentration of each gases are [tex]\rm PCl_{5}[/tex] is 0.0077 mol/L, [tex]\rm PCl_{3}[/tex] and [tex]\rm Cl_{2}[/tex] is 0.177 mol/L.

Learn more about the concentration of the gases here:

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Answer:

Here you go buddy. Good Luck

Explanation:

Chemical formula of a compound tells us about the number of atoms of elements that are present in a compound.

For the given options:

1. Nitric acid

This is an acid in which one hydrogen, 1 nitrogen and 3 oxygen atoms are present. The chemical formula for this compound is [tex]HNO_3[/tex]

2. Sulfurous acid

This is an acid in which two hydrogen, 1 sulfur and 3 oxygen atoms are present. The chemical formula for this compound is [tex]H_2SO_3[/tex]

3. Hypochlorous acid

This is an acid in which one hydrogen, 1 chlorine and 1 oxygen atoms are present. The chemical formula for this compound is [tex]HClO[/tex]

4. Ammonia

This is an acid in which three hydrogen and 1 nitrogen atoms are present. The chemical formula for this compound is [tex]NH_3[/tex]

5. Sulfuric acid

This is an acid in which one hydrogen, 1 sulfur and 4 oxygen atoms are present. The chemical formula for this compound is [tex]H_2SO_4[/tex]

Answer:

- 228.6 kJ/mol.

Explanation:

∵ ΔGrxn = ∑ΔGf, products - ∑ΔGf, reactants

4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O,  

∴ ΔGrxn = [6(ΔGf, H₂O) + 4(ΔGf, NO)] - [4(ΔGf, NH₃) + 5(ΔGf, O₂)]

ΔGrxn = – 957.9 kJ, ΔGf, H₂O = ??? KJ/mol, ΔGf, NO = 86.71 kJ/mol, ΔGf, NH₃ = - 16.66 kJ/mol, ΔGf, O₂ = 0.0 kJ/mol.

∴ – 957.9 kJ = [6(ΔGf, H₂O) + 4(86.71 kJ/mol)] - [4(- 16.66 kJ/mol) + 5(0.0 kJ/mol)].

– 957.9 kJ = 6(ΔGf, H₂O) + 346.8 kJ/mol + 66.64 kJ/mol

– 957.9 kJ = 6(ΔGf, H₂O) + 413.8 kJ/mol

6(ΔGf, H₂O) = – 957.9 kJ - 413.8 kJ/mol = - 1372 kJ/mol.

∴ ΔGf, H₂O = (- 1372 kJ/mol)/6 = - 228.6 kJ/mol.

The correct answer would be B. high concentration of hydroxyl ions, as bleach has a basic pH of about 13.

Hope this helps:)

A solution's hydronium ion concentration must fall as the concentration of hydroxide ions rises. In this instance, [H3O+] [OH-], and the remedy is regarded as basic. A high concentration of hydroxyl ions would expect bleach to have.

The chemical term for the diatomic anion OH is hydroxide. Other names for hydrogen dioxide include hydroxyl, hydroxyl radical, and hydroxide ion. It is made up of an atom of hydrogen and one of oxygen that are joined together by a covalent bond. A negative electric charge is present in the hydrogen.

A diatomic anion with the chemical formula OH is hydrogen oxide. It has a negative electric charge and is made up of two atoms of oxygen and hydrogen that are bound together by a single covalent bond.

A basic solution and a large concentration of hydroxide ions are indicated by a low pOH value.

Thus, option B is correct.

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Answer:

[tex]\boxed{\text{(E) }1.0 \times 10^{-3} \text{ mol/L and pH = 3}}[/tex]

Explanation:

1. Calculate the concentration of hydronium ion

We can use an ICE table to organize the calculations.

                      HA + H₂O ⇌ H₃O⁺ + A⁻

I/mol·L⁻¹:     0.100                  0        0

C/mol·L⁻¹:       -x                    +x      +x

E/mol·L⁻¹:   0.100 - x              x         x

[tex]K_{\text{a}} = \dfrac{\text{[H}_{3}\text{O}^{+}]\text{A}^{-}]} {\text{[HA]}} = 1.0 \times 10^{-5}\\\\\dfrac{x^{2}}{0.100 - x} = 1.0 \times 10^{-5}\\\\\\\text{Check for negligibility of }x\\\\\dfrac{ 0.100 }{1.0 \times 10^{-5}} = 10 000 > 400\\\\\therefore x \ll 0.100\\\\\\x^{2} = 0.100 \times 1.0\times 10^{-5} = 1.00 \times 10^{-6}\\\\x = \sqrt{1.00 \times 10^{-6}} = 1.0\times 10^{-3}\\\\\rm [H$_{3}$O$^{+}$]= x mol$\cdot$L$^{-1}$ = 1.0 $\times$ 10$^{-3}$ mol$\cdot$L$^{-1}$[/tex]

2. Calculate the pH

[tex]\text{pH} = -\log{\rm[H_{3}O^{+}]} = -\log{1.0 \times 10^{-3}} = \boxed{\mathbf{3}}[/tex]

the answer is in the picture

Answer: 2HCL (aq) + ZN(s) ZnCl2(s) = H2(g)

Explanation:

Answer:

Explanation:

A hydrocarbon with a double bond in its carbon skeleton is an alkene and has the general form:

This is, the number of hydrogen atoms is twice the number of carbon atoms.

On the other hand, alkanes have only single bonds, and the compounds with a triple bond in its carbon skeleton are alkynes.

Review each choice:

1) C₃H₈:

2) C₂H₆

3) CH₄

4) C₂H₄

So, this is the correct answer.

5) C₂H₂

Answer:

The wood

Explanation:

The block of wood shall float in the water while the iron key would sink due to the weight.

The iron key is easier to find in the bathtub as it will sink due to its density, while the wood floats. This behavior is explained by Archimedes' principle concerning buoyant force and the displacement of water.

Between the iron key and the piece of wood, the iron key would be easier to find because it would sink to the bottom of the bathtub due to its higher density compared to water. Objects denser than water, such as iron, will not float and instead displace a volume of water equal to their own volume as they sink. This concept is explained by Archimedes' principle, which states that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Since iron is much denser than water, it displaces a small volume of water before reaching the bottom of the tub. On the other hand, wood is less dense than water and therefore floats on the surface. This is because the wood displaces a volume of water equal to its weight before it is completely submerged, allowing it to float.

In the bathtub experiment mentioned in the question, marbles were dropped into a partially filled bathtub sink to the bottom. While part of their weight is supported by the buoyant force, the downward force on the bottom of the tub increases by exactly the weight of the marbles because the water displaced by the marbles has to go somewhere, exerting an equal force downward.

Answer:

4909.486Kj/mol

Explanation:

the heat would be required to change steam at 100°c to water at 100°c then change the water at that temperature to water at 0°c then change water at 0°c to ice at 0°c then ice at 0°c to ice at -15°c

Answer : The heat released is, 319.28 kJ

Solution :

The conversions involved in this process are :

[tex](1):H_2O(g)(100^oC)\rightarrow H_2O(l)(100^oC)\\\\(2):H_2O(l)(100^oC)\rightarrow H_2O(l)(0^oC)\\\\(3):H_2O(l)(0^oC)\rightarrow H_2O(s)(100^oC)\\\\(4):H_2O(s)(0^oC)\rightarrow H_2O(s)(-15^oC)[/tex]

Now we have to calculate the enthalpy change.

[tex]\Delta H=n\times \Delta H_{condensation}+[n\times c_{p,l}\times (T_{final}-T_{initial})]+n\times \Delta H_{freezing}+[n\times c_{p,s}\times (T_{final}-T_{initial})][/tex]

where,

[tex]\Delta H[/tex] = enthalpy change = ?

Mass of water = 105 g

Moles of water = [tex]\frac{\text{Mass of water}}{\text{Molar mass of water}}=\frac{105g}{18g/mole}=5.83mole[/tex]

[tex]c_{p,s}[/tex] = specific heat of solid water = [tex]36.4J/(mol.^oC)[/tex]

[tex]c_{p,l}[/tex] = specific heat of liquid water = [tex]75.4J/(mol.^oC)[/tex]

[tex]\Delta H_{freezing}[/tex] = enthalpy change for freezing = enthalpy change for fusion = - 6.01 KJ/mole = - 6010 J/mole

[tex]\Delta H_{condensation}[/tex] = enthalpy change for condensation = enthalpy change for vaporization = -40.67 KJ/mole = -40670 J/mole

Now put all the given values in the above expression, we get

[tex]\Delta H=5.83mole\times -40670J/mole+[5.83mole\times 75.4J/(mol.^oC)\times (0-100)^oC]+5.83mole\times -6010J/mole+[5.83mole\times 36.4J/(mol.^oC)\times (-15-0)^oC][/tex]

[tex]\Delta H=-319285.78J=-319.28KJ[/tex]     (1 KJ = 1000 J)

Negative sign indicates that the heat is released during the process.

Therefore, the heat released is, 319.28 KJ