Which equation shows a physical change?
A.Pb(NO3)2 (aq) + 2KI(aq) → 2KNO3(aq) + PbI2(s)
B. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
C.2H2O(l) → 2H2(g) + O2(g)
D.H2O(g) → H2O(s)

Answers

Answer 1

Answer:

The correct option is D

Explanation:

A physical change is a change in which no new substance is formed and can be easily reversible.

Of the options provided, option D is correct because gaseous water (steam) can be converted to solid water (ice) through freezing and can be reversed by heating up the solid water. Thus, this process does not involve the formation of any new substance.

Note that the processes of freezing and heating described must pass through the liquid phase.


Related Questions

At constant pressure for which of the reactions shown below should Delta H be greater than Delta E°?
1.2 SO2(g) + O2(g) - 2 SO3(g)
II. C5H12(9) + 8 O2(g) - 5 CO2(g) + 6 H20(1)
III. H2(g) + Br2(g) → 2 HBr(9),
IV. N204(9) - 2 NO2(g)

Answers

Answer: [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]

Explanation:

The realtion between enthalpy change and internal energy change is:

[tex]\Delta H=\Delta E+\Delta n_gRT[/tex]

where,

=  enthalpy of the reaction

= internal energy of the reaction

[tex]\Delta n_g[/tex] = change in the gaseous moles of the reaction = Moles of product - Moles of reactant

R = gas constant

T = temperature

1. [tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]

[tex]\Delta n_g[/tex] = 2-3 = -1

2. [tex]C_5H_{12}(g)+8O_2(g)\rightarrow 5CO_2(g)+6H_2O(l)[/tex]

[tex]\Delta n_g[/tex] = 5-9 = -4

3. [tex]H_2(g)+Br_2(g)\rightarrow 2HBr(g)[/tex]

[tex]\Delta n_g[/tex] = 2-2 = 0

4. [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex]

[tex]\Delta n_g[/tex] = 2-1 = 1

Thus reaction . [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]

At constant pressure the given reaction that shows ΔH would be greater than ΔE is;

IV); N₂0₄(g) 2NO₂(g)

In chemistry, he meaning of ΔH and ΔE are;

- ΔH means the change in enthalpy, which is heat content.

- ΔE means the change in energy of a system.

Now, for a closed system the relationship between ΔH and ΔE is given by;

ΔH = ΔE + PΔV

where PΔV = ΔnRT

Thus; ΔH = ΔE + ΔnRT

where Δn = number of moles of product in the gaseous state - number of moles of reactants.

Thus, if Δn is negative, then ΔE would be greater than ΔH but if Δn is positive, then ΔH would be greater than ΔE

I) 2SO₂(g) + O₂(g) ⇒ 2SO₃(g)

number of moles of product = 2

number of moles of reactants = 2 + 1 = 3

Δn = 2 - 3

Δn = -1 and so ΔE would be greater than ΔH

II) C₅H₁₂(g) + 8O₂(g) ⇒ 5CO₂(g) + 6H₂0(l)

number of moles of product = 5 (6 is not used because water is in liquid and not gas)

number of moles of reactants = 8 + 1 = 9

Δn = 5 - 9

Δn = -4 and so ΔE would be greater than ΔH

III) H₂(g) + Br₂(g) → 2HBr(g)

number of moles of product = 2

number of moles of reactants = 1 + 1 = 2

Δn = 2 - 2

Δn = 0 and so ΔE would be equal to ΔH

IV) N₂0₄(g) → 2NO₂(g)

number of moles of product = 2

number of moles of reactants = 1

Δn = 2 - 1

Δn = +1 and so ΔH would be greater than ΔE

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GIVING BRAINLIEST! Please answer with 5-7 sentences.

Describe exothermic reactions in terms of energy.

Answers

Answer:Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light. In an exothermic reaction, energy is released because the total energy of the products is less than the total energy of the reactants.

Explanation:lol

What is the frequency of a photon that has a wavelength of 754 um? ​

Answers

Answer:

Explanation:

What is the frequency of a photon that has a wavelength of 754 um? ​

which of the following disease is not transmitted by mosquito
(a) Dengue (b) Malaria (c)Bain fever (d)Pneumonia​

Answers

pneumonia is not transmitted by mosquito

what
your events made Gautam Buddha to
go in search of the truth?​

Answers

Answer:

The Buddha (also known as Siddhartha Gotama or Siddhārtha Gautama[note 3] or Buddha Shakyamuni) was a philosopher, mendicant, meditator, spiritual teacher, and religious leader who lived in Ancient India (c. 5th to 4th century BCE).[5][6][7][note 4] He is revered as the founder of the world religion of Buddhism, and worshipped by most Buddhist schools as the Enlightened One who has transcended Karma and escaped the cycle of birth and rebirth.[8][9][10] He taught for around 45 years and built a large following, both monastic and lay.[11] His teaching is based on his insight into duḥkha (typically translated as "suffering") and the end of dukkha – the state called Nibbāna or Nirvana.

The Buddha was born into an aristocratic family in the Shakya clan but eventually renounced lay life. According to Buddhist tradition, after several years of mendicancy, meditation, and asceticism, he awakened to understand the mechanism which keeps people trapped in the cycle of rebirth. The Buddha then traveled throughout the Ganges plain teaching and building a religious community. The Buddha taught a middle way between sensual indulgence and the severe asceticism found in the Indian śramaṇa movement.[12] He taught a spiritual path that included ethical training and meditative practices such as jhana and mindfulness. The Buddha also critiqued the practices of Brahmin priests, such as animal sacrifice.

A couple of centuries after his death he came to be known by the title Buddha, which means "Awakened One" or "Enlightened One".[13] Gautama's teachings were compiled by the Buddhist community in the Suttas, which contain his discourses, and the Vinaya, his codes for monastic practice. These were passed down in Middle-Indo Aryan dialects through an oral tradition.[14][15] Later generations composed additional texts, such as systematic treatises known as Abhidharma, biographies of the Buddha, collections of stories about the Buddha's past lives known as Jataka tales, and additional discourses, i.e, the Mahayana sutras.

Explanation:

Which of the following biogeochemical cycles does not contain a molecule in a gaseous state?

Answers

The phosphorus cycle does not have a gaseous component. The inorganic form of phosphorus, phosphate, enters the soil from the weathering of rocks.

In bulk, jelly beans cost 18 cents per ounce.
What is the cost of the jelly beans in dollars per pound?

Answers

Explanation:

One pound is equal to 16 ounces. One pound of jelly beans cost $2.88p

Answer:

$2.88

Explanation:

Introduction:
Briefly describe the physical behavior you investigated.
What is the exploration about?
What are you trying to discover?
Relate to any previous work.
Use new vocabulary words, if you can.

Answers

Answer: im not sure if this is the best answer but i wrote, "This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Explanation: hope this helps.

This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

Thus, For persons with autism, life can be incredibly stressful at times, and their behaviour may be an indication of their utter exasperation or suffering in reaction to a variety of pressures.

Some people struggle with the idea of time and sequencing, thus this can involve onerous tasks, meeting new people, experiencing unpleasant sensory stimuli, a change in routine, switching activities, or having to wait for anything.

The individual may have realized how effective their actions could be in influencing their environment. A behaviour that was initially a reaction to physical discomfort or frustration may later develop into a strategy for evading a request or getting rid of an uncomfortable circumstance.

Thus, This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."

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The question is Incomplete, the complete question is:

Briefly describe the physical behavior?

What is the exploration about?

What are you trying to discover?

Relate to any previous work.

Use new vocabulary words, if you can.

In the exploration, I was a bird trying to eat bugs placed in different backgrounds. Each bug was adifferent color, and the color either matched or stood out against the background. What I wastrying to discover was how creatures adapted to their environment and if blending in with theirenvironment helped them or hindered them. I discovered that yes, blending in with theenvironment helps creatures survive.

What type of weathering causes mineral. composition of rocks to change?
A:chemical weathering
B:General weathering
C:Mechanical weathering
D:Permeable weathering

Answers

I think d sorry if i’m wrong!

Answer:

Chemical weathering

Explanation:

which of these is the smallest unit?
ds
ks
cs
ms

Answers

Answer:

ks

Explanation:

Is it right

Perform the following calculation with the
correct number of significant figures.
12.62 +2.3 + 0.34 = ?

Answers

the answer is 15.26.

Please help!!!Which statement accurately describes relationship between weight and mass? If the picture is black just don’t answer

Answers

Answer:

A

Explanation:

Mass is a raw measurement, weight is effected by gravity

A. Weight is an objects mass multiplied by the amount of gravitational force acting on that object.
The formula for weight is:
W=mg
Which is weight equals mass x gravity

What is the percent yield for carbon dioxide if 10.0 grams of carbon
monoxide yielded 12.81 grams of carbon dioxide from the reaction
below?
2 CO + O2 → 2 CO2

Answers

The percent yield : 81.5%

Further explanation

Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

2CO+O₂⇒2CO₂

mol CO(MW=28,01 g/mol)

[tex]\tt \dfrac{10}{28.01}=0.357[/tex]

mass CO₂ (theoretical)(MW=44,01 g/mol)

[tex]\tt 0.357\times 44.01=15.712~g[/tex]

the percent yield :

[tex]\tt \dfrac{12.81}{15.712}\times 100\%=81.5\%[/tex]

you can answer this for free but im not asking im just saying- why does baby donald trump cartoon with out the funny faces look like boss baby- please dont tell me boss baby is donald trump it would ruin me

Answers

Answer:

who knows..

Explanation:

Answer:

oh wow- i-

Explanation:

What is the answer please help

Answers

Answer: C

Explanation:

there should be 2 molecules which leaves A and C. But there should be 1 white circle and 3 black circles which means C is the right answer

The answer to your question is C

A student measures out exactly 0.0970 g of salicylic acid and carries out an aspirin synthesis using salicylic acid, acetic anhydride, heat, and an acid catalyst. Salicylic acid is the limiting reagent in this reaction, which yields 0.1030 g of aspirin. What is the percent yield for the reaction?

Answers

Answer: 106.19%

Explanation:

percent yield = actual/theo * 100%

our theoretical yield is the limiting reagent and then we have our actual given

.1030/.0970* 100% = 106.19%

The percent yield of prepared aspirin is 102.84%.

What is percent yield?

Percent yield is defined as the ratio of actual yield to the theoretical yield  multiplied by 100. If the actual and theoretical yield are same then the percent yield is 100%.If actual yield is less than the theoretical yield then the percent  yield is less than 100%.Reason of this condition arising is the incompletion of reaction  or loss of sample during recovery process.

In cases where percent yield is over 100% it indicates that more sample is recovered than the predicted amount.This condition arises when there are other simultaneous reactions taking place leading to the formation of product. It can also arise if there is incomplete removal of impurities from the sample .

By using the formula of percent yield , yield of aspirin is calculated as,

0.1030/0.1264 ×100=81.48%.

Thus, the percent yield of aspirin is 81.48%.

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In an atomic model, what particals are found inside the nucleas of an atom. Thanks

Answers

Answer:

protons and nuetrons

Explanation: protons have a positive charge and nuetrons which have no charge together the make up the middle of an nuclues in a atom. i may be incorrect please tell me if i am


Which type of drug commonly marketed to consumers does not require a prescription?

A. antidepressant
B. blood pressure medication
C. pain reliever

Answers

C. pain reliever
ex. tylenol, aleve, etc.

Answer:

pain reliever

Explanation:

Cu+2AgNO 3 Cu(NO 3 ) 2 +2Ag what are the reactants

Answers

Answer:

Cu + 2AgNo3 is the reactants

Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other is empty. What will happen when the valve is opened? (3 points)

a
Oxygen molecules will remain in their original jar because of the very high density of the oxygen molecules.

b
Oxygen molecules will remain in their original jar because there is enough space in the original jar.

c
Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.

d
Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.

Answers

Answer:

d) Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.

Explanation:

Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.

Intermolecular forces hold the molecules of matter together in a particular state of matter.

Gases have the weakest intermolecular forces between them. As such, the molecules of gases are isolated from each other and they move at very high velocities.

Due to weak intermolecular forces between the molecules of oxygen gas, when the valve between the two jars is opened, oxygen gas spreads evenly throughout the both jars.

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What is the correct formula that would result from the combination
of the two ionic species?

Answers

The correct formula : BeSO₄

Further explanation

Chemical formula shows the composition number of the constituent atoms

Polyatomic ion consists of 2 or more ions

The equal charge of the two ions will cancel each other out, while the different charges of the two ions will be crossed each other

Be²⁺ (monatomic ion) has a positive charge of +2, while SO₄²⁻ (polyatomic ion) has a negative -2 charge, so that the two charges with the same magnitude but with different charges cancel each other out so that the compound form is BeSO4

Calculate the average atomic mass of an element containing 39.9% of atoms with a mass of 69 amu and 60.1% of atoms with a mass of 71 amu. Show your work for credit and round your answer to one decimal place.

Answers

Answer:

70.202 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Abundance (A%) = 39.9%

Mass of A = 69 amu

Isotope B:

Abundance (B%) = 60.1%

Mass of B = 71 amu

Average atomic mass =?

The average atomic mass of the element can be obtained as follow:

Average atomic mass = [(Mass of A × A%)/100] + (Mass of B × B%)/100]

= [(69 × 39.9)/100] + [(71 × 60.1)/100]

= 27.531 + 42.671

= 70.202 amu

Therefore, the average atomic mass of the element is 70.202 amu

State what would most likely happen to the rate of enzyme action if the temperature were reduced by 10 degrees. Support your answer.

Answers

Answer:

Explanation:afa

Which layer of the sun is responsible for producing the light shown in the picture above? Radiative zone Convective zone Photosphere Chromosphere

Answers

Answer:

Answer Expert Verified

The lights shown in the figure comes from the outermost layer of the Sun. This layer is called photosphere. This is the layer from where the light of the Sun is radiated, before travelling through space and reaching us.

Answer:

That guy is wrong, I believe it is c

Explanation:

Choose the most electronegative atom from the following: K, Mg, As, CI
Potassium (K)
Chlorine (CI)
Arsenic (As)
Magnesium (Mg)

Answers

Answer:

Cl

Explanation:

Electronegativity increases as you move up and to the right of the periodic table. For example, Florine is the most electronegative element.

What mass of Cu(s) is electroplated by running 19.5 A of current through a Cu2 (aq) solution for 4.00 h

Answers

Answer:

92.46 g

Explanation:

The reaction is

[tex]Cu^{2+}+2e^-\rightarrow Cu[/tex]

I = Current = 19.5 A

t = 4 hours = [tex]4\times 60\times 60=14400\ \text{s}[/tex]

F = Faraday constant = 96485.33 C/mol

Molar mass of copper = 63.546 g/mol

Charge is given by

[tex]Q=It\\\Rightarrow Q=19.5\times 14400\\\Rightarrow Q=280800\ \text{C}[/tex]

Moles of electrons is given by

[tex]\dfrac{Q}{F}=\dfrac{280800}{96485.33}\\ =2.91\ \text{mol}[/tex]

Moles of copper is

[tex]\dfrac{1}{2}\times \dfrac{Q}{F}=\dfrac{1}{2}\times 2.91\\ =1.455\ \text{mol}[/tex]

Mass of copper would be

[tex]\text{Moles}\times \text{Molar mass of copper}=1.455\times 63.546\\ =92.46\ \text{g}[/tex]

The mass of copper electroplated is 92.46 g.

During a chemical reaction, how do the substances that form differ from the substances that react?

Answers

What the guy above me said

In which of the following elements is the least
amount of energy required to remove the most
loosely bound electron from an atom in the gaseous
state?
A) Sr
B) Ar
C) Al
D C

Answers

Answer:

A) Sr

Explanation:

Strontium will require the least amount of energy to remove the most loosely bound electrons from its atom in gaseous state.

This parameter is known as the ionization energy. It is defined as the readiness of an atom to lose an electron.

Metals in group 1 and 2 generally have very low ionization energy due to their large electropositivity The more electropositive a metal is, the lower its ionization energy. This is the reason why strontium will have the least ionization energy.

Which of these are properties of metals? Select all that apply.
A. ductile
B. semiconductors
C. shiny
D. gases at room temperature
E. malleable​

Answers

Answer:

E,A,D i beleve

Explanation:

im pretty sure thats what it is

A 1.59 mol sample of Kr has a volume of 641 mL. How many moles of Kr are in a 4.41 L sample at the same temperature and pressure?

Answers

Answer:

The correct answer is 10.939 mol ≅ 10.94 mol

Explanation:

According to Avogadro's gases law, the number of moles of an ideal gas (n) at constant pressure and temperature, is directly proportional to the volume (V).

For the initial gas (1), we have:

n₁= 1.59 mol

V₁= 641 mL= 0.641 L

For the final gas (2), we have:

V₂: 4.41 L

The relation between 1 and 2 is given by:

n₁/V₁ = n₂/V₂

We calculate n₂ as follows:

n₂= (n₁/V₁) x V₂ = (1.59 mol/0.641 L) x 4.41 L = 10.939 mol ≅ 10.94 mol

The number of moles is 10.94 mol.

The calculation is as follows:

As per the Avogadro gases law, the no of moles at the same pressure & temperature should be proportional to the volume.

The following formula should be used:

[tex]n_1\div V_1 = n_2\div V_2\\\\n_2= (n_2\div V_1) \times V_2\\\\ = (1.59 mol\div 0.641 L) \times 4.41 L[/tex]

= 10.939 mol

= 10.94 mol

Therefore we can conclude that the number of moles is 10.94 mol.

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