How long should you hold the iron on the hair to heat the strand and set the base ?


A) 5 seconds
B) 15 seconds
C) 30 seconds
D) 1 minute

Entropy is INCREASING when a snowman melts, a document goes through paper shredder, silver tarnishes, while it is DECREASING when dissolved sugar precipitates, water vapor forms droplets and water cools down.

Entropy can be defined as the degree of randomness or disorder of a particular system.

Entropy is equal to zero (0) for a perfectly ordered system.

Heat increases the entropy of the system because more energy excites the molecules and it increases the amount of random activity.

Moreover, the cooling decreases the entropy of the system because molecules are more ordered and it decreases the amount of random activity.

In conclusion, entropy is INCREASING when a snowman melts, a document goes through paper shredder, silver tarnishes, while it is DECREASING when dissolved sugar precipitates, water vapor forms water droplets and the water cools down.

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Answer:

1. The coefficients are: 1, 3, 2

2. From the balanced equation, we obtained the following:

3 moles oxygen, O2 reacted.

2 moles of Hydrogen sulfide, H2S reacted.

2 moles of water were produced.

2 moles of sulphur dioxide, SO2 were produced.

Explanation:

1. Determination of the coefficients of the equation.

This is illustrated below:

P2O5(s) + H2O(l) <==> H3PO4(aq)

There are 2 atoms of P on the left side and 1 atom on the right side. It can be balance by putting 2 in front of H3PO4 as shown below:

P2O5(s) + H2O(l) <==> 2H3PO4(aq)

There are 2 atoms of H on the left side and 6 atoms on the right side. It can be balance by putting 3 in front of H2O as shown below:

P2O5(s) + 3H2O(l) <==> 2H3PO4(aq)

Now the equation is balanced.

The coefficients are: 1, 3, 2.

2. We'll begin by writing the balanced equation for the reaction. This is given below:

2H2S(g) + 3O2(g) => 2H2O(l) + 2SO2(g)

From the balanced equation above,

3 moles of oxygen, O2 reacted with 2 moles of Hydrogen sulfide, H2S to produce 2 moles of water, H2O and 2 moles of sulphur dioxide, SO2.

Answer:

Alternative C would be the correct choice.

Explanation:

The other three choices are not related to the given circumstances. So that option C would be the appropriate choice.

Answer:

Option B. 30 KJ.

Explanation:

The following data were obtained from the question:

Temperature (T) = 5000 K

Enthalpy change (ΔH) = – 220 kJ/mol

Change in entropy (ΔS) = – 0.05 KJ/mol•K

Gibbs free energy (ΔG) =...?

The Gibbs free energy, ΔG can be obtained by using the following equation as illustrated below:

ΔG = ΔH – TΔS

ΔG = – 220 – (5000 x – 0.05)

ΔG = – 220 – (– 250)

ΔG = – 220 + 250

ΔG = 30 KJ

Therefore, the Gibbs free energy, ΔG is 30 KJ.

Answer:

The drawing that represents the result of placing all three liquids into the same graduated cylinder will have the liquid arranged one on top of the other from top to bottom in the order of A, C, B.

Explanation:

The image with the options is not provided in this question, but I can answer this fairly so that you can pick from the question, the correct drawing.

We know that two or more immiscible liquids contained together in a container will always separate in the order of their density from top to bottom, with the densest at the bottom, and the least densest at the top. In this case, liquid A is the least densest, and liquid B is the densest. Liquid A will stay on top, and liquid B will be at the bottom. Liquid C will be in between liquid A and liquid B.

Answer:

Sb

Explanation:

The periodic trend for atomic radius is that it decreases from left to right and increases from top to bottom, therefore the elements with the larger atomic radius will be the ones which are closest to the bottom left corner of the periodic  table. Since all of these elements are in the same group, the one with the largest atomic radius will be the one at the "bottom", and that is Sb.

Answer:

0.81167 amu

Explanation:

Number of protons=42

Number of neutrons = 54

Mass of all the 42 protons = 42× 1.00728= 42.30576 amu

Mass of all 54 neutrons= 54 × 1.008665 = 54.46791 amu

Calculated mass of protons and neutrons in Mo-96 nucleus= 42.30576 amu + 54.46791 amu= 96.77367 amu

Actual mass of Mo-96 nucleus= 95.962 amu

Therefore mass defect of Mo-96 nucleus= 96.77367 amu - 95.962 amu = 0.81167 amu

Answer:

Bleaching Powder's chemical formula is CaOCl2 and is called Calcium Oxychloride. It is prepared on dry slaked lime by chlorine gas. 2. ... It gives calcium chloride, chlorine and water when bleaching powder reacts with hydrochloric acid.

Explanation:

Answer:

Part C: P2 = 0.30 atm

Part D: V1 = 16.22 L.

Explanation:

Part C:

Initial pressure (P1) = 2.67 atm

Initial volume (V1) = 5.54 mL

Final pressure (P2) =.?

Final volume (V2) = 49 mL

The final pressure (P2) can be obtained as follow:

P1V1 = P2V2

2.67 x 5.54 = P2 x 49

Divide both side by 49

P2 = (2.67 x 5.54)/49

P2 = 0.30 atm

Therefore, the final pressure (P2) is 0.30 atm

Part D:

Initial pressure (P1) = 348 Torr

Initial volume (V1) =?

Final pressure (P2) = 684 Torr

Final volume (V2) = 8.25 L

The initial volume (V1) can be obtained as follow:

P1V1 = P2V2

348 x V1 = 684 x 8.25

Divide both side by 348

V1 = (684 x 8.25)/348

V1 = 16.22 L

Therefore, the initial volume (V1) is 16.22 L

1. 21.67g/ml

2. aluminium

Explanation:

1. density = mass/volume

385.8/17.8= 21.67ml

2. 1g/ml=0.1g/cm^3

21.67g/ml = 2.167g/cm^3

..... substance is probably aluminium

1.  the density of the metal is 21.67g/ml

2.  This metal is most likely aluminum

1.

[tex]density = mass \div volume[/tex]

[tex]385.8\div 17.8= 21.67ml[/tex]

2.

1g/ml=0.1g/cm^3

So,  

21.67g/ml = 2.167g/cm^3

Therefore,  substance is probably aluminum

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Answer:

Following are the answer to this question:

Explanation:

The value of pH solution is =5.17 So, the p^{OH}:

[tex]p^{OH}[/tex]=14-56.17

      =8.823

The volume of the [tex]NH_{3}[/tex] = 40.00 ml  

convert into the liter= 0.040L

The value of the concentrated [tex]NH_{3}[/tex] =0.10 M

The volume of the [tex]NH_{4}Cl[/tex]= 50.00 ml

convert into the liter= 0.050L

 The value of concentrated [tex]NH_{4}Cl[/tex]= 0.10 M

The volume of the [tex]H_{2}So_{4}[/tex]= 30 ml

convert into the liter= 0.030L  

The value of concentrated [tex]H_2So_4[/tex]=0.05 M

Calculating total volume=(0.40+0.050+0.030)

                                       =0.120 L

calculating the new concentrated value of [tex]NH_3[/tex] = [tex]\frac{0.10\times 0.040}{0.120}= 0.33 \ M[/tex]

calculating the new concentrated value of [tex]NH_4Cl[/tex]= [tex]\frac{0.050\times 0.10}{0.120}= 0.04166 \ M[/tex]calculating the new concentrated value of [tex]H_2So_4= \frac{0.030\times 0.05}{0.120}= 0.0125 \ M[/tex] when 1 mol [tex]H_2So_4[/tex] produced 2 mols [tex]H^{+}[/tex] so, 0.0125 in [tex]H_2So_4[/tex]produced:

[tex]=4 \times (2 \times 0.0125) \ mol H^{+}\\\\= 0.025 mol H^{+}[/tex]

create the ICE table:    

[tex]NH_3 \ \ \ \ \ \ \ \ + H^{+} \ \ \ \ \ \ \longrightarrow NH_4^{+}[/tex]                    

I (m)       0.033(m)            0.025                       0.04166

C            -0.025                 -0.025                       + 0.025  

E            8.3\times 10^{-3}     0                    0.0667

now calculating pH:

when ph= 8.83:

[tex]P^{H}= p^{kb}|+ \log\frac{[NH_4^{+}]}{[NH_3]}\\\\8.83=p^{kb}+\log\frac{0.0667}{8.3 \times 10^{-3}}\\\\p^{kb}=8.83-0.9069\\\\ \ \ \ =7.7231 \\\\\ The P^{kb} \ for \ NH_3 \ is =7.7231\\\\\ The P^{kb} \ for N^{+}H_4=14-7.7231\\\\\ \ \ \ \ \ =6.2769[/tex]

Answer:

Coordinate or r = (7,9).

Explanation:

Data obtained from the question include the following:

Mid point = (8,7)

Coordinate of S = (9,5)

Coordinate of r =...?

We shall determine the coordinate of r as follow:

Let the coordinate of r be (x2, y2)

Mid point = (x1 + x2)/2 , (y1 + y2)/2

Mid point = (8,7)

Coordinate of S = (9,5)

x1 = 9

y1 = 5

x2 =?

y2 =?

The value of x2 can be obtained as follow:

8 = (x1 + x2)/2

8 = (9 + x2)/2

Cross multiply

9 + x2 = 2 × 8

9 + x2 = 16

Collect like terms

x2 = 16 – 9

x2 = 7

The value of y2 can be obtained as follow:

5 = (y1 + y2)/2

7 = (5 + y2)/2

Cross multiply

5 + y2 = 2 × 7

5 + y2 = 14

Collect like terms

y2 = 14 – 5

y2 = 9

Coordinate of r = (x2, y2)

Coordinate or r = (7,9)

A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation: AB → A + B. Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.

Answer:

New pH = 3.84

Explanation:

First of all we may think that if the buffer has pH 3.98 and we're adding H⁺, pH's buffer will be lower, as the [H⁺] is been increased.

Let's determine the moles of each compound:

0.23 M . 1.3L = 0.299 moles of NaBz

0.38 M . 1.3L = 0.494 moles of HBz

We add 0.058 of HCl, which is the same as 0.058 moles of H⁻

HCl →  H⁺  +  Cl⁻

As we add the moles of protons, these are going to react to the Bz⁻

In the buffer system we have these dissociations:

NaBz  →  Na⁺  +  Bz⁻

HBz →  H⁺  + Bz⁻

So, as we add protons, we have a new equilibrium:

          Bz⁻      +      H⁺       ⇄   HBz    

In    0.299         0.058          0.494

Eq   0.241               -              0.552

Protons are substracted to benzoate, so the [HBz] is now higher than before. We calculate the new pH, with the Henderson Hasselbach equation

pH = pKa + log (Bz⁻/HBz)

pH = 4.20 + log (0.241 / 0.552) → 3.84

The given question is incomplete, the complete question is:

A chemist adds 200.0 ml of a 0.52M barium chlorate (Ba(CIO3)2) solution to a reaction flask. Calculate the mass in grams of barium chlorate the chemist has added to the flask. Round your answer to significant digits.

Answer:

The correct answer is 32 grams.

Explanation:

Based on the given solution, the molarity of barium chlorate solution given is 0.52 M, this shows that the solution will comprise 0.52 moles in 1 L or 1000 ml of the solution.  

Therefore, in 200 ml, it will comprise 0.52/1000 × 200 moles of Ba(ClO₃)₂,  

= 0.52/1000 × 200 = 0.104 moles

The molecular mass of Ba(ClO₃)₂ is 304.23 gram per mole

So, the mass of Ba(ClO₃)₂ in 0.104 moles will be,  

= 304.23 g/mol × 0.104

= 31.639 grams or 32 grams.  

Answer:

The answer to this question is 0.072km/h

Answer:

[tex]\large \boxed{5.1}[/tex]

Explanation:

1. Initial concentrations of reactants

[SO₂] = (3.8 mol)/(75 L) = 0.0507 mol·L⁻¹

 [O₂] = (7.0 mol)/(75 L) = 0.0933 mol·L⁻¹

2. Equilibrium concentration of SO₃

[SO₃] = (1.5 mol)/(75 L) = 0.0200 mol·L⁻¹

3. Set up an ICE table

                      2SO₂     +      O₂     ⇌     2SO₃

I/mol·L⁻¹:     0.0507         0.0933             0

C/mol·L⁻¹:        -2x                -x                +2x

E/mol·L⁻¹:   0.0507-2x    0.0933-x           2x

4. Calculate x

We know the final concentration of SO₃ is 0.0200 mol·L⁻¹, so

2x = 0.0200

x = 0.0100

5. Find the final concentrations of the reactants

Insert the numbers into the ICE table.

                      2SO₂     +       O₂     ⇌     2SO₃

I/mol·L⁻¹:     0.0507         0.0933             0

C/mol·L⁻¹:    -0.0200       -0.0100      +0.0200

E/mol·L⁻¹:     0.0307         0.0833        0.0200

6. Calculate K

[tex]K_{\text{eq}} = \dfrac{\text{[SO$_{3}$]}^{2}}{\text{[SO}_{2}]^{2}\text{[O$_{2}$]}} = \dfrac{0.0200^{2}}{0.0307^{2}\times0.0833} =\mathbf{5.1}\\\\\text{The value of the equilibrium constant is $\large \boxed{\mathbf{5.1}}$}[/tex]

Answer:

There is insufficient information to know direction of these systems

Explanation:

Delta H of a reaction is defined as the amount of energy involved when it occurs. The ΔH < 0 represents the reaction will release energy and ΔH > 0 the reaction will absorb energy.

As you can see, ΔH doesn't give information about the direction of a reaction (Spontaneity). In fact, to know spontaneity of a reaction you must know ΔG involved in this reaction.

As the reactions have ΔH but not ΔG,

Answer:

0.00295M

Explanation:

Mass Concentration = mass/vol

= 0.203 g/ 0.02414 L = 8.409 g/L

But molarity = Mass conc / molar mass

∴ Molar mass(mol/L) = mass conc / molarity

= .84909 / 0.0295

= 285.06 g/mol

If 1 mol of green stock - 285.06g

? mol - 0.203 g

= 0.00071213 g

= 0.00071213 g / .2414L = 0.0095 mol/L.

Answer:

5.643 kJ

Explanation:

The quantity of heat released or absorbed by a substance (Q) is given by the equation:

Q = mcΔT

Where m is the mass of the substance, c is the specific heat of substance and ΔT is the difference between the final temperature and the initial temperature.

Given that:

m = 45 g, Final temperature = 48°C, Initial temperature = 18°C, c = specific heat of water = 4.18 J/g°C

ΔT = Final temperature - Initial temperature = 48°C - 18°C = 30°C

The quantity of heat is:

Q = mcΔT = 45 g × 4.18 J/g°C × 30°C = 5643 J

Q = 5.643 kJ

Answer:

a) [tex]\Delta G=2.6kJ[/tex]

b) [tex]\Delta G=-979.57kJ[/tex]

c) [tex]\Delta G=264.21kJ[/tex]

Explanation:

Hello,

In this case, in each reaction we must subtract the Gibbs free energy of formation the reactants to the Gibbs free energy of formation of the products considering each species stoichiometric coefficients. In such a way, the Gibbs free energy of formations are:

[tex]\Delta _fG_{H_2}=\Delta _fG_{I_2}=0kJ/mol\\\Delta _fG_{HI}=1.3kJ/mol\\\Delta _fG_{CO_2}=-394.4kJ/mol\\\Delta _fG_{CO}=-137.3 kJ/mol\\\Delta _fG_{NH_3}=16.7 kJ/mol\\\Delta _fG_{HCl}=-95.3kJ/mol\\\Delta _fG_{MnO_2}=465.37kJ/mol\\\Delta _fG_{Mn}=0kJ/mol\\\Delta _fG_{NH_4Cl}=-342.81kJ/mol[/tex]

So we proceed as follows:

a)

[tex]\Delta G=2\Delta _fG_{HI}-\Delta _fG_{H_2}-\Delta _fG_{I_2}\\\\\Delta G=2*1.3\\\\\Delta G=2.6kJ[/tex]

b)

[tex]\Delta G=\Delta _fG_{Mn}+2*\Delta _fG_{CO_2}-\Delta _fG_{MnO_2}-2*\Delta _fG_{CO}\\\\\Delta G=0+2*-394.4-465.37-2*-137.3\\\\\Delta G=-979.57kJ[/tex]

c)

[tex]\Delta G=\Delta _fG_{NH_3}+\Delta _fG_{HCl}-\Delta _fG_{NH_4Cl}\\\\\Delta G=16.7-95.3-(-342.81)\\\\\Delta G=264.21kJ[/tex]

Regards.

Answer:

Explanation:

.

Answer:

139.33 g of magnesium chloride, MgCl2.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(aq)

Next, we shall determine the mass of Mg that reacted and the mass of MgCl2 from the balanced equation.

This is illustrated below:

Molar mass of Mg = 24 g/mol

Mass of Mg from the balanced equation = 1 x 24 = 24 g

Molar mass of MgCl2 = 24 + (2x35.5) = 95 g/mol

Mass of MgCl2 from the balanced equation = 1 x 95 = 95 g

From the balanced equation above,

24 g of Mg reacted to produce 95 g of MgCl2.

Finally, we shall determine the mass of MgCl2 produced by reacting 35.2 g of Mg.

This can be obtained as follow:

From the balanced equation above,

24 g of Mg reacted to produce 95 g of MgCl2.

Therefore, 35.2 g of Mg will react to produce = (35.2 x 95)/24 = 139.33 g of MgCl2.

From the calculations made above, 139.33 g of magnesium chloride, MgCl2 were produced.

Answer:

0.792g of triphenyl bromide are produced.

Explanation:

The reaction of triphenyl methanol with HBr is:

triphenyl methanol + HBr → Triphenyl bromide.

Reaction (1:1), 1 mole of HBr reacts per mole of triphenyl methanol.

To know the mass of triphenyl bromide assuming a theoretical yield (Yield 100%) we need to find first limiting reactant:

Moles triphenyl methanol (Molar mass: 260.33g/mol) =

0.220g × (1mol / 260.33g) = 8.45x10⁻³ moles Triphenyl methanol

Moles HBr (Molar mass: 80.91g/mol; 33%=33g HBr/100mL) =

0.60mL ₓ (33g / 100mL) ₓ (1mol / 80.91g) = 2.45x10⁻³ moles HBr

As amount of moles of HBr is lower than moles of triphenyl methanol, HBr is limiting reactant.

As HBr is limiting reactant, moles produced of triphenyl bromide = moles HBr = 2.45x10⁻³ moles

As molar mass of triphenyl bromide is 323.2g/mol, mass of triphenyl bromide is:

2.45x10⁻³ moles × (323.2g / mol) =

Answer:

The pressure of the gas sample will be  0.954 atm.​

Explanation:

Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container, when the temperature is constant. That is, if the pressure increases, the volume decreases; conversely if the pressure decreases, the volume increases.

Boyle's law is expressed mathematically as:

Pressure * Volume = constant

o P * V = k

To determine the change in pressure or volume during a transformation at constant temperature, the following is true:

P1 · V1 = P2 · V2

That is, the product between the initial pressure and the initial volume is equal to the product of the final pressure times the final volume.

In this case:

Replacing:

0.609 atm* 19.9 L= P2* 12.7 L

Solving:

[tex]P2=\frac{0.609 atm* 19.9 L}{12.7 L}[/tex]

P2= 0.954 atm

The pressure of the gas sample will be  0.954 atm.​

Answer:

E. 8.08 x 10⁴.

Explanation:

Hello,

In this case, for the reaction:

[tex]CH_2O(g) + 2H_2(g) \rightleftharpoons CH_4(g) + H_2O(g)[/tex]

We can compute the Gibbs free energy of reaction via:

[tex]\Delta G\°=\Delta H\°-T\Delta S\°[/tex]

Since both the entropy and enthalpy of reaction are given at 298 K (standard temperature), therefore:

[tex]\Delta G\°=-94.9kJ-(298K)(-224.2\frac{J}{K}*\frac{1kJ}{1000kJ} )\\\\\Delta G\°=-28.1kJ[/tex]

Then, as the equilibrium constant is computed as:

[tex]K=exp(-\frac{\Delta G\°}{RT} )[/tex]

We obtain:

[tex]K=exp(-\frac{-28.1kJ/mol}{8.314x10^{-3}\frac{kJ}{mol* K}}*298K )\\\\K=8.08 x10^4[/tex]

For which the answer is E. 8.08 x 10⁴.

Best regards,

Answer:

0.44 moles

Explanation:

Given that :

A mixture of water and graphite is heated to 600 K in a 1 L container. When the system comes to equilibrium it contains 0.17 mol of H2, 0.17 mol of CO, 0.74 mol of H2O, and some graphite.

The equilibrium constant [tex]K_c= \dfrac{[CO][H_2]}{[H_2O]}[/tex]

The equilibrium constant  [tex]K_c= \dfrac{(0.17 )(0.17)}{0.74}[/tex]

The equilibrium constant [tex]K_c= 0.03905[/tex]

Some O2 is added to the system and a spark is applied so that the H2 reacts completely with the O2.

The equation for the reaction is :

[tex]H_2 + \dfrac{1}{2}O_2 \to H_2O \\ \\ 0.17 \ \ \ \ \ \ \ \ \ \to0.17[/tex]

Total mole of water now = 0.74+0.17

Total mole of water now = 0.91 moles

Again:

[tex]K_c= \dfrac{[CO][H_2]}{[H_2O]}[/tex]

[tex]0.03905 = \dfrac{[0.17+x][x]}{[0.91 -x]}[/tex]

0.03905(0.91 -x) = (0.17 +x)(x)

0.0355355 - 0.03905x = 0.17x + x²

0.0355355 +0.13095 x -x²

x² - 0.13095 x - 0.0355355 = 0

By using quadratic formula

x = 0.265  or   x = -0.134

Going by the value with the positive integer; x = 0.265 moles

Total moles of CO in the flask when the system returns to equilibrium is :

= 0.17 + x

= 0.17 + 0.265

= 0.435 moles

=0.44 moles (to two significant figures)

Answer:

0.394 atm

Explanation:

Mathematically, when we increase the pressure of a gas, we are increasing its concentration and when we decrease the pressure, we are decreasing its concentration.l at same temperature

What this means is that pressure and concentration are directly proportional.

Representing concentration by c and pressure by p, we have;

P1/C1 = P2/C2

From the question;

P1 = 0.719 atm

P2 = ?

C1 = 429.7 ppm

C2 = 235.3 ppm

Now, we can rewrite the equation to be;

P1C2/C1 = P2

Substituting the values we have;

0.719 * 235.3/429.7 = 0.394 atm

Answer:

The Lewis structure is attached with the answer -

Explanation:

Lewis structure or Lewis dot diagram are diagrams or representation of showing the bonding between different or same atoms of a molecule in any and also shows lone pairs of electrons that may exist in the molecule as dots.

HBrO₄ is bromine oxoacid which is also known as perbromic acid. It is a unstable inorganic compound.

The Lewis structure is attached in form of image with representation of lone pairs of electrons.

Answer:

0.460 g  

Explanation:

Mass of flask + acid = 98.778 g

Mass of flask            = 98.318 g

Mass of acid             =  0.460 g