Which of the following is an exothermic reaction?

a solid to a liquid

a gas change to a liquid

a liquid to a gas

a solid to a gas

Answers

Answer 1
i’m pretty sure it’s b !
Answer 2

Answer:

liquid to gas

Explanation:

when boiling water when evaporating heat is given out


Related Questions

3. The name of the functional group in the following compound
CH3 - CH2 - CH2 - CH-CH2 - CH3
1
CH3 – CH2
a. Methyl
b. Ethyl
C. Propyl
d. Isopropy!

Answers

Answer: a.) Methyl would be the answer.

Explanation:

Compare Dalton’s and Democritus’ ideas.

Answers

Answer:

please give me brainlist and follow

Explanation:

The key difference between Democritus and Dalton atomic theory is that the Democritus atomic theory is an ancient theory that scientists later refined and elaborated whereas Dalton atomic theory is a comparatively modern, scientific theory that we cannot discard due its important statements.

Help please thank youu

Answers

Answer:

The KE increases.

Explanation:

KE=1/2(mv²)

So, as the velocity increases, kinetic energy also increases.

which bond does water atom share​

Answers

Answer:

Covalent bonds

Explanation:

A water molecule consists of two atoms of hydrogen linked by covalent bonds to the same atom of oxygen. Atoms of oxygen are electronegative and attract the shared electrons in their covalent bonds.

visible light travels from place to place as a

Answers

Answer:

Light can travel in three ways from a source to another location: (1) directly from the source through empty space; (2) through various media; (3) after being reflected from a mirror.

Explanation:

Lab: Measuring pH Table or
Lab Report please ( just link it ) please

Answers

Answer:

sorry my phone died lol but here are the answers

<3

A 0.6467-g portion of manganese dioxide was added to an acidic solution in which 1.1701 g of a chloride-containing sample was dissolved. Evolution of chlorine took place as a consequence of the following reaction: After the reaction was complete, the excess was collected by filtration, washed, and weighed, and 0.3104 g was recovered. Express the results of this analysis in terms of percent aluminum chloride.

Answers

Answer:

29.39% of AlCl₃ in the sample

Explanation:

Based on the reaction:

MnO₂(s) + 2Cl⁻ + 4H⁺ → Mn²⁺ + Cl₂(g) + 2H₂O

We can find the amount of chloride in solution with the amount of MnO₂ that reacted as follows:

Initial mass MnO₂ = 0.6467g

Recovered mass = 0.3104g

Mass that reacted = 0.6467g - 0.3104g = 0.3363g

Moles MnO₂ -Molar mass: 86.9368g/mol-:

0.3363g * (1mol / 86.9368g) = 3.868x10⁻³ moles MnO₂

Moles Cl⁻:

3.868x10⁻³ moles MnO₂ * (2mol Cl⁻ / 1mol MnO₂) = 7.737x10⁻³ moles Cl⁻

Moles of AlCl₃ and mass -Molar mass AlCl₃: 133.34g/mol-:

7.737x10⁻³ moles Cl⁻ * (1mol AlCl₃ / 3mol Cl⁻) = 2.579x10⁻³ moles AlCl₃

2.579x10⁻³ moles AlCl₃ * (133.34g / mol) =

0.3439g of AlCl₃ are present in the sample.

The percent is:

0.3439g of AlCl₃ / 1.1701g * 100 =

29.39% of AlCl₃ in the sample

The dehydration of the alcohol functional group is a widely used reaction in organic chemistry. The mechanism is generally accepted to always operate via an ______ step-wise process. The _____ mechanism process will always produce (after dehydration) a ________________ style alkene as major product. The driving force for the production of this ________________ style alkene product is generally going to be determined by stability of the ________ ____________.

Answers

Answer:

EliminationEliminationZaitsevZaitsevCarbocation

Explanation:

The mechanism is generally accepted to always operate via an ELIMINATION step-wise process. The ELIMINATION mechanism process will always produce (after dehydration) a ZAITSEV style alkene as major productThe driving force for the production of this ZAITSEV style alkene product is generally going to be determined by stability of the CARBOCATION

Elimination mechanism is the removal of two substituents  from a molecule in either a one- or two-step mechanism

Carbocation is a molecule containing a positive charged carbon atom and three bonds

The mechanism is generally accepted to always operate via an elimination step-wise process. The elimination mechanism process will always produce (after dehydration) a Zaitsev style alkene as major product. The driving force for the production of this Zaitsev style alkene product is generally going to be determined by stability of the carbocation.

What is dehydration?

Dehydration is a process in which a water molecule releases from the given compound to form an unsaturated compound.

Dehydration process of alcohol is done by the elimination reaction in which water molecule eliminate and due to this dehydration we get an unsaturated product alkene. This dehydration process is go through the formation of carbocation which in turn forms the product. Stability of the product is determined by the Zaitsev rule and according to this rule most substituted product is the major and stable product.

Hence correct options are: Elimination, elimination, Zaitsev, Zaitsev and carbocation.

To know more about Zaitsev rule, visit the below link:
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If objects with a greater mass have greater gravitational pull, why is our solar
system, Sun, planets and asteroids, NOT pulled into Alpha Centauri A?

Answers

Answer:

It's too far away

Explanation:

According to classical mechanics, gravitational pull is inversely proportional to the distance squared; as the distance increases, the gravitational pull decreases at a faster and faster rate. Since Alpha Centauri A is a few lightyears (Tens of trillions of kilometers away), without even needing to calculate the force of gravity, it is very miniscule.

What type of Weathering is important to sand storms on Mars? Physical or
Chemical?

Why would 3D printing be important on Mars and why would you use material from the surface of Mars.

We could "print" things that we need on Mars.
We could print things that we need on Mars and use material that is already on the planet
It would be so cool
The cost would be less expensive.

Answers

Answer:

1. Physical Weathering

2. Option B

Explanation:

1. Physical weathering

On Mars, there are two types of weathering agents a) wind and b) acid fog. Thus, they will carry out only physical weathering

2. Option B

3D can be used to produce things that are required on the Mars and also the locally available raw material can be used for printing thereby saving the cost.

What will be the pH of a buffer solution containing an acid of pKa7.5, with an acid concentration exactly one fourth of that of the conjugate base

Answers

Answer: pH of buffer solution is 8.1

Explanation:

The formula for the Henderson–Hasselbalch equation is:

[tex]pH=pK_a+\log\frac{[A^-]}{[HA]}[/tex]

[tex]pH[/tex] is the concentration of [tex][H^+][/tex]

[tex]pK_a[/tex] is the acid dissociation constant,

[tex]A^-[/tex] and [tex]HA[/tex] are concentrations of the conjugate base and starting acid.

Putting in the values we get:

[tex]pH=7.5+\log\frac{x}{\frac{x}{4}}[/tex]

[tex]pH=8.1[/tex]

Thus pH of buffer solution is 8.1

A student dissolves 10.7 g of lithium chloride (LiCl) in 300. g of water in a well-insulated open cup. He then observes the temperature of the water rise from 22.0 °C to 28.6 °C over the course of 3.8 minutes. Use this data, and any information you need from the ALEKS Data resource:
LiCl(s) rightarrow Li+(aq) + Cl-(aq)
You can make any reasonable assumptions about the physical properties of the solution. Note for advanced students: it's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the known and published values for this reaction.
1) Is this reaction exothermic, endothermic, or neither?
2) If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.
3) Calculate the reaction enthalpy delta Hrxn per mole of LiCl.

Answers

Answer:

1) Exothermic.

2) [tex]Q_{rxn}=-8580J[/tex]

3) [tex]\Delta _rH=-121.0kJ/mol[/tex]

Explanation:

Hello there!

1) In this case, for these calorimetry problems, we can realize that since the temperature increases the reaction is exothermic because it is releasing heat to solution, that is why the temperature goes from 22.0 °C to 28.6 °C.

2) Now, for the total heat released by the reaction, we first need to assume that all of it is absorbed by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:

[tex]Q_{rxn}=-m_{Total}C(T_2-T_1)\\\\Q_{rxn}=-(300g+10.7g)*4.184 \frac{J}{g\°C} (28.6\°C-22.0\°C)\\\\Q_{rxn}=-8580J[/tex]

3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case LiCl, we proceed as follows:

[tex]\Delta _rH=\frac{Q_{rxn}}{n_{LiCl}} \\\\\Delta _rH=\frac{-8580J}{10.7g*\frac{1mol}{150.91g} }*\frac{1kJ}{1000J} \\\\\Delta _rH=-121.0kJ/mol[/tex]

Best regards!

One liter of gas A at 1.0 atm pressure has a temperature of 25°C while the same volume and pressure of gas B has a temperature of 50°C. What else do you know about these two gases?

A) There are twice as many moles of gas B than gas A.
B) Gas A has twice the molar mass of gas B.
C) Gas A has more kinetic energy than gas B.
D) Gas B has more kinetic energy than gas A.

Answers

Answer:

b

Explanation:

What type of chemical reaction is this?

2Na + 2H20 - 2NaOH + H2

Answers

Single replacement reaction

What happens if more solute is added to a saturated solution?

Answers

Answer:

A saturated solution is a mixture in which the maximum amount of a given solute has been dissolved into the solvent. ... At this point adding more solute will not change the concentration of the solution; adding more solute will simply result in more solid at the bottom of the solution.

Answer:

will not change

Explanation:

A saturated solution is a mixture in which the maximum amount of a given solute has been dissolved into the solvent. ... At this point adding more solute will not change the concentration of the solution; adding more solute will simply result in more solid at the bottom of the solution.

2. Some nitrogen at a pressure of 35.75 p.s.i is in a 100 L container. If the container's volume is reduced to 2250 ml then what is the resulting pressure?​

Answers

Answer:

1455.6

Explanation: you first convert 2250ml to l by dividing by 1000 so you get 2.25l then you use Boyles law which is p1v1=p2v2 then insert values

35.75*100=p2*2.25 then divide both sides by 2.25 then you get 1455.6

These properties best describe which body (Gases Surface, 75%H, 25% He, Zones)
(18 Points)

Planet

or

Sun
NO LINKS

Answers

Answer:sun

Explanation:The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by ... When hydrogen fusion in its core has diminished to the point at which the Sun is no longer in . Sunlight on the surface of Earth is attenuated by Earth's atmosphere, so that less power arrives

1.Are forests a renewable or non-renewable resource? Give reasons for both possibilities

Answers

Answer:

Forests are renewable

Explanation:

Forests can grow again, but it takes forever to grow a new one so it shouldn't be taken for granted! You can remake a whole new forest, but it will take around 50 years and a lot of animals will die without them before that time comes!

But then again, it could be a non-renewable resources; because it takes so long to grow a new one!

Hope this helps!

. Which one is NOT an INDICATOR that a chemical has occurred
A) Gas is produced
B) Precipitate is produced
C) Change in energy
D) Change in mass

Answers

Ima guess D) change in mass

Cosmic rays are

A. High energy radiation produced in the ozone layer.
B. High energy radiation produced by the earth’s core.
C. None of these.
D. High energy radiation produced by the sun.

Answers

A. High energy radiation produced in the ozone layer. (:

I have a lab report I have to do for Chemistry on Edge, the lab is on Enthalpy.
please let me know if you need further information.

Answers

Answer:

I need further information.

Explanation:

Extra information is needed for you to know the correct information.

What is Enthalpy?

It is a thermodynamic quantity that is equal to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.

Enthalpy is nothing but energy and they are of 4 types in thermodynamics-

1. Internal Energy, U

2. Heat enthalpy, H

3. Helmholtz enthalpy, A

4. Gibb's Free enthalpy, G

The total energy of a system cannot be measured directly because the internal energy contains components that are unknown, not easily accessible, or are not of interest in thermodynamics. Generally, a change in enthalpy is the expression for measurements at constant pressure because it simplifies the information of energy transfer.

Therefore, Extra information is needed for you to know the correct information.

Learn more about Enthalpy, here:

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What is the value for AG at 5000 K if AH = -220 kJ/mol and S= -0.05 kJ/(mol-K)?

A. -195 kJ
B. -470. kJ
C. 30 kJ
D. 470 kJ

Answers

Answer:

C. 30 kJ

Explanation:

Hello there!

In this case, in agreement to the thermodynamic definition of the Gibbs free energy, in terms of enthalpy of entropy:

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

It is possible to calculate the required G by plugging in the given entropy and enthalpy as shown below:

[tex]\Delta G=-220kJ/mol-5000K*-0.05kJ/mol*K\\\\\Delta G=30kJ/mol[/tex]

Therefore, the answer is C. 30 kJ .

Best regards!

How much energy ( in joule ) does the Sun emit in one day (24 hours)? I've previously answered with 3.32, but it was incorrect. Please help thanks.

Answers

It is about 3.86 which is 10⁶⁶ watts

Answer:

410 quintillion Joules or 430,000,000,000,000,000,000 Joules

Rusting is a chemical reaction between Iron metal [Fe(s)] and oxygen gas [O2(g)] in a slightly acidic environment. Rusting is actually a multi-step reaction, however it has the net overall reaction of:

4Fe+3O2--->2FeO3

If 100.0 g of iron metal are converted into rust, how many moles of rust will have formed? (Assume unlimited oxygen gas.)
*Hint* You already converted 100.0 g of Fe into moles of Fe in a previous question, start there.

Answers

Answer:

0.895 mole of Fe₂O₃.

Explanation:

We'll begin by calculating the number of mole in 100 g of Fe. This can be obtained as follow:

Molar mass of Fe = 56 g/mol

Mass of Fe = 100 g

Number of mole of Fe =?

Mole = mass / molar mass

Number of mole of Fe = 100 / 56

Number of mole of Fe = 1.79 mole

Finally, we shall determine the number of mole of Fe₂O₃ produced by the reaction of 100 g (i.e 1.79 moles) of Fe. This can be obtained as follow:

4Fe + 3O₂ — > 2Fe₂O₃

From the balanced equation above,

4 moles of Fe reacted to produce 2 moles of Fe₂O₃.

Therefore, 1.79 moles of Fe will react to produce = (1.79 × 2)/4 = 0.895 mole of Fe₂O₃.

Thus, 0.895 mole of Fe₂O₃ was obtained from the reaction.

Which one is it for a brialiest

Answers

I’m confused about the question

if a gas sample has a pressure of 30.7 kPa at 273 K, what does the temperature have to decrease to lower the pressure to 28.4 kPa?​
253K
268K
262K

Answers

253 K

P1/T1 = P2/T2

P1 = 30.7 kPa
T1 = 273 K
P2 = 28.4 kPa

Solve for T2 —> T2 = P2T1/P1
T2 = (28.4 kPa)(273 K) / (30.7 kPa) = 253 K

Which of the following must be overcome by a rocket's thrust?

Answers

Answer:

the payloads weight

Explanation:

a p e x on the ground stream

Answer:

The payload's weight

Explanation:

i just took the test on a pex :)

A buffered solution _______. Select the correct answer below: fails to keep hydronium and hydroxide ion concentrations nearly constant when strong acids or bases are added. maintains a constant or nearly constant pH when small amounts of strong acids or bases are added. acts to keep the hydroxide ion concentration nearly constant. acts to keep the hydronium ion concentration nearly constant.

Answers

I believe it is the second one

The correct option for the given question about Buffer Solution is Option B) which is maintains a constant or nearly constant pH when small amounts of strong acids or bases are added.

What is a Buffer Solution?When a little quantity of acid or base is diluted or added, the buffer solution undergoes very slight variations in its hydrogen ion concentration (pH). pH may be maintained in buffer solutions, which are mixtures of a weak acid and its conjugate base or a weak base and its conjugate acid.Acidic and alkaline buffers are the two main groups into which buffer solutions are commonly categorized.A weak acid and its salt are combined with a strong base to create an acidic buffer, which has an acidic pH.A weak base, its salt, and a strong acid are combined to create an alkaline buffer, which has a basic pH.

Thus we conclude that when weak acids or bases are supplied in small amounts, the pH remains steady or almost constant.

Learn more about Buffer Solution here:

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Which metals will switch in this single replacement reaction Zn + MgO -->

a. Mg and Zn

b. Zn and O

c. Mg and O

d. This is not a single replacement reaction

Answers

Answer:

D

Explanation:

Magnesium is more reactive than zinc so no reaction will take place

Which salt preparation uses a burette and a pipette

Answers

potassium chloride from potassium hydroxide and hydrochloric acid

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