Which phase change is exothermic?

Which Phase Change Is Exothermic?

Answers

Answer 1

Answer:

B. Solidification

Hope this helped! :)

Answer 2
c. Melting ! pls lmk if that was correct !:)

Related Questions

A chemical breaks down in a flow-balanced, steady-state CFMR according to first-order reaction kinetics. At steady state, the upstream and downstream concentration of the chemical are 15 mg/L and 5 g/m3. Water is being treated at a rate of 0.42 m3/sec. The volume of the tank is 500,000 liters. Assuming a first-order reaction, what is the rate constant

Answers

Answer:

[tex]k =0.101 \ min^{-1}[/tex]

Explanation:

From the given information:

The initial concentration of a chemical [tex]C_{AO} = 15 \ mg/L[/tex]

The final concentration is [tex]C_A = 5 \ g/m^3[/tex] = 5 mg/L

Volume flow rate [tex]V_o = 0.42 \ m^3/sec[/tex]

Volume of the tank V = 500 000 L = 500 m³

The time t is determined by using the formula:

[tex]t= \dfrac{V}{V_o}[/tex]

[tex]t= \dfrac{500 \ m^3}{0.42 \ m^3/sec}[/tex]

t = 1190.47 sec

t ≅ 19.8 min

The rate of the decay constant is:

[tex]kt= \dfrac{C_{AO}-C_{A}}{C_A} \\ \\ k = \dfrac{1}{19.8}( \dfrac{15-5}{5})[/tex]

[tex]k =0.101 \ min^{-1}[/tex]

How long did it take to get the Hubble Telescope into space?

Answers

2 years! Let me know if it’s wrong or correct.

What is the volume of 45 g of Hydrogen gas (H2) at STP?

Answers

Volume>500•L
hope this helps!!!

For the following exothermic reaction system at equilibrium:
H2O(g) CO(g) CO2(g) H2(g)
Choose the changes that will increase the value of K.
a. Decrease the volume (constant T)
b. Add H2O(g) (constant T)
c. Remove H2(g) (constant T)
d. Add a catalyst (constant T)
e. Add CO2(g) (constant T)
f. Increase the temperature
g. Decrease the temperature

Answers

Answer:

See explanation.

Explanation:

Hello there!

In this case, for the chemical reaction:

[tex]H_2O(g) CO(g)\rightleftharpoons CO_2(g) H_2(g)[/tex]

It is widely known that the the only factor altering the equilibrium constant is the temperature because of its thermodynamic definition:

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

Which is temperature dependent on the denominator and on the Gibbs free energy of reaction. In such a way, the answers can be just f and g, as the other factors modify Q (reaction quotient) rather than K. Thus, we can discuss about f and g:

f. This would increase K if the Gibbs free energy of reaction is positive (nonspontaneous).

g. This would increase K if the Gibbs free energy of reaction is negative (spontaneous).

It is important to discuss those two because the Gibbs free energy is not given.

Regards!

1 interpret geochemistry in your words. 2. how can you explain that the solar system (sun, all planets and satellites) has all been formed from a special nebula ?​

Answers

Explanation:

(I only know this thing vaguely lol)

1.) It's the study of the chemistry that is happening here on earth that is not bounded by a laboratory.

2.) The early gas clouds compressed and formed a star we now call the sun and the massive gravitational pull of this star grabbed nearby debris and the debris formed and compressed into the planets and moons that we know today.

Complete the sentence using the correct word: conduction,
convection or thermal energy.
The method of heat transfer that occurs when particles move
through a fluid is called

Answers

Answer:

Convection

Explanation:

Convection definition:

the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

The method of heat transfer that occurs when particles move through a fluid is called convection.

Convection relies on the principle of fluid flow, where hotter particles become less dense and rise while cooler particles sink due to their increased density.

This movement creates a continuous circulation of the fluid, enabling the transfer of thermal energy. As the hot particles rise, they carry their thermal energy with them, and as the cooler particles sink, they absorb heat from their surroundings.

Convection is also observed in natural phenomena such as ocean currents, air currents, and even the movement of magma in the Earth's mantle.

To learn more about the convection, follow the link:

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Consider 4 g N2O5, in a test tube. [Given: Ar(N) = 14, Ar(O) = 16]
What is the percentage oxygen in N2O5? (Give your answer in 4 significant figures)​

Answers

Answer:

74.08%

Explanation:

We'll begin by calculating the mass of

Oxygen in 4 g of N₂O₅. This can be obtained as follow:

Molar mass of N₂O₅ = (14×2) + (16×5)

= 28 + 80

= 108 g/mol

Mass of oxygen in N₂O₅ = 5 × 16 = 80 g

Mass of oxygen in 4 g of N₂O₅

= 80 / 108 × 4

= 2.963 g

Finally, we shall determine the percentage of oxygen in 4 g of N₂O₅. This can be obtained as follow:

Mass of oxygen = 2.963 g

Mass of N₂O₅ = 4 g

Percentage of oxygen =?

Percentage of oxygen = mass of oxygen / mass of N₂O₅ × 100

Percentage of oxygen = 2.963 / 4 × 100

Percentage of oxygen = 74.08%

How many molecules of O2 will be required to produce 28.8 g of water?

Answers

I think 1.67 x 10^20

find the pH of a 0.00476M HCI solution​

Answers

Ans:2.3

Explanation:

pH = -log[H+(aq)]

= -log[0.00476]

=2.3

As HCl solution is monobasic. Each molecule ionizes in water to form ONE hydrogen ion. So the H+(aq) is equal to its molarity.

2.3 is he pH of a 0.00476 M HCI solution and this value tells that solution is acidic in nature.

How we calculate pH of any solution?

pH of any solution can be define as the negative log of the concentration of the H⁺ ions.

In the question given that:

Concentration of HCl solution = 0.00476 M

Concentration of H⁺ ions is equal to concentration of HCl solution as it completely ionize into their ions. So, pH can be calculated as:

pH = -log[H⁺] = -log[0.00476] = 2.3

Hence, pH of the solution is 2.3.

To know more about pH, visit the below link:

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A sample of nitrogen gas is stored in a 0.500 L flask at 101.3 atm. The gas is transferred to a 0.750
L flask. What is the pressure of nitrogen in the second flask if the temperature remains constant?

Answers

Answer:

67.5 atm

Explanation:

To answer this problem we can use Boyle's law, which states that at constant temperature the pressure and volume of a gas can be described as:

P₁V₁=P₂V₂

In this case:

P₁ = 101.3 atm

V₁ = 0.500 L

P₂ = ?

V₂ = 0.750 L

We input the data:

101.3 atm * 0.500 L = P₂ * 0.750 L

And solve for P₂:

P₂ = 67.5 atm

explain how convection currents affect sea breezes and land breezes.
pls help

Answers

In the evening , air above the land, being more heated, expands, rises up and the colder air from above the sea surface blows towards the land to take its place. This sets up he convection currents which forms the sea breeze.

There are 3 ways that heat travels: conduction, convection, and radiation. Convection happens in fluids. What happens is that as a fluid heats up, it expands. Since it has expanded, it is less dense than the fluid next to it, so it rises above it. In the atmosphere, with sea and land breezes, as either the ground or sea is warmer than the other, it heats the air above it. This air rises above the cooler air next to it. The cooler air then moves in to take the place of the warmer air that just rose up. This air then is warmed by the ground or water beneath it, so it then rises, and so on.

what is the difference between transmutation and natural radioactivity​

Answers

Answer:

o diferença chave entre a radioatividade e a transmutação é que a radioatividade se refere à transmutação natural, enquanto a transmutação se refere à mudança de um elemento químico em outro por meios naturais ou artciais.Tanto a radioatividade quanto a transmutação são processos químicos que envolvem a mudança de núcleos atômicos para formar um novo elemento químico a partir de um elemento químico existente. A radioatividade é um tipo de processo de transmutação

Explanation:

mais informação em; ahttps://pt.strephonsays.com/radioactivity-and-transmutation-9500

How many grams of KCl will be formed from 0.500 grams of KClO3?

Answers

Answer:

0.31g KCl

Explanation:

Before we can start, we have to wonder, how many moles of KCl is formed from KClO3? To figure that out we have to make a balanced equation.

KClO3 -> KCl + O2

How do I know it makes O2? Looking back at the problem they're asking for KCl, which has less ions than KClO3 so it must have been broken down. So we can say it's a decomposition type of reaction. We can't just slap on O3, we know oxygen is one of our diatomic elements that usually exists as O2 so we'll put it down as O2 and balance our equation.

2KClO3 -> 2KCl + 3O2

Now that we know every 2 moles of KClO3 makes 2 moles of KCl, this is our mole to mole ratio. Knowing the ratio between the 2 compounds in our problem is the stepping stone from converting from grams KClO3 -> moles KClO3 -> moles KCl -> grams KCl.

1. Let's first convert grams KClO3 -> moles KClO3

[tex]0.500g KClO3 x \frac{1 mol}{123g KClO3} = 0.0041 mol KClO3[/tex]

2. Convert moles KClO3 -> moles of KCl using our mole to mole ratio

[tex]0.0041 mol KClO3 x \frac{2 mol KCl}{2 mol KClO3} = 0.0041 mols KCl[/tex]

3. Convert moles KCl -> grams KCl

[tex]0.0041 mol KCl x\frac{75g KCl}{1 mol} = 0.31g KCl[/tex]

A jet is goes from 180km/s to 139km/s in 22 seconds. What is it's acceleration?
14. V=
15. Vp =
16. t=
17a=

Answers

180 km/s V= 25



explanation: i had the same assignment

calculate the mass of butane needed to produce 65.5 g of carbon dioxide

Answers

You take the mass of carbon dioxide, 56.8g, divide by its molar mass, 44.01g/mol, to produce the moles of carbon dioxide. This is multiplied by the molar ratio of butane/CO2, (2/8) = 1/4, which gives the moles of butane required to produce the carbon dioxide.

The mass of a substance is the product of the moles and the molar mass. 65.5 g of carbon dioxide will be able to produce 21.62 grams of butane.

What is mass?

The mass of a reactant or a product is estimated by the number of moles and the molar mass of the substance.

The combustion reaction of methane is shown as,

2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O

Given,

Molar mass of butane = 58.12 g/mol

Mass of carbon dioxide = 65.5 g

Molar mass of carbon dioxide = 44.01 g/mole

Moles of carbon dioxide are calculated as,

Moles = mass ÷ molar mass

= 65.5 ÷ 44.01

= 1.488 moles

From the above reaction, two moles of butane produce eight moles of carbon dioxide. So, 1.488 moles of carbon dioxide will be produced from,

2 × 1.488 ÷ 8 = 0.372 moles

The moles of butane required is 0.372 moles

The mass of butane from moles is calculated as,

Mass = moles × molar mass

= 0.372 × 58.12 g/mole

= 21.62 gms

Therefore, 21.62 gm of butane is required to produce 65.5 g of carbon dioxide.

Learn more about mass here:

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how many grams of ammonia produced from 1000 grams of N2?

Answers

Answer:

N2 + 3H2 ———> 2NH3

As we know 1000 grams ammonia is 58.82 moles so according to unitary method,

2 mole NH3 formed by 1 mole N2 hence 58.82 NH3 will be given by 29.41 moles N2.

No. Of moles = given mass/molar mass

Implies that

Mass of nitrogen required = 29.41*28 = 823.48 grams.

Explanation:

Arenediazoniums can undergo electrophilic aromatic substitutions with a wide variety of activated aromatic compounds to yield new azo dyes.

a. True
b. False

Answers

B false
I did this last year and it’s false


Graphite is one of the allotropes of carbon
a) Define the term allotropy
b) Identify the other allotrope of carbon
c) State two uses of graphite ​

Answers

Answer:

When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite. Every carbon atom is covalently bonded at the four corners of the tetrahedron to four other carbon atoms.

Why is soap able to break down oils and fats?

Answers

Answer:

When you build up a soapy lather, the molecules help lift the dirt, oil and germs from your skin

Explanation:

Soap molecules have one end that bonds with water and the other end that bonds with oils and fats .

Hope this helped!!

3 Zn + 2 H3PO4 → 3 H2 + Zn3(PO4)2

How many grams of Zn are needed in order to produce 0.15 g of H2?

Answers

Answer: 4.87 g

Explanation:

We know that for every 3 moles of zinc that are consumed, 3 moles of hydrogen are produced (we can reduce this to the number of moles of zinc consumed = moles of hydrogen produced)

We know that the formula mass of hydrogen is 2(1.00794)=2.01588 g/mol, so in 0.15 g, there is about 0.15/2.01588 = 0.074409191023275 moles.

This means that about 0.074409191023275 moles of zinc are needed, and since the atomic mass of zinc is 65.409 g/mol, the answer is (0.074409191023275)(65.409)=4.87 g

Identify the reaction type of the chemical reaction below. Check all that apply.
Mg (s)+2 HCl (aq) MgCl 2 (aq)+H 2 (g)

Answers

Answer:

The type of reaction is a single-replacement reaction.

Explanation:

Mg switches places with H, leaving H by itself.

What type of ions have names ending in -ide?
O only cations
O. only anions
O only metal ions
O only gaseous ions

Answers

Answer:

Only anions

Explanation:

Polyatomic positive ions often have common name ending with the suffix anions

How many molecules of carbon tetrafluoride, CF4, are in 176 grams of CF4?

Answers

Answer:

1.2*10^24 molecules of CF4

Explanation:

the molar mass of cf4 is 88.0043 g/mol

176/88.0043 = 2 moles of CF4

Then multiply by avogadro's number (6.022*10^23) to get the number of molecules

2*6.022*10^23 = 1.2*10^24 molecules of CF4

There are 1.204 × 10²⁴ molecules of carbon tetrafluoride in 176 grams of CF4.

HOW TO CALCULATE NUMBER OF MOLECULES:

The number of molecules in a substance can be calculated by multiplying the number of moles in the substance by Avogadro's number:

no. of molecules = no. of moles × 6.02 × 10²³

The number of moles in CF4 can be calculated as follows:

moles of CF4 = mass of CF4 ÷ molar mass of CF4.

Molar mass of CF4 = 12 + 19(4)

Molar mass of CF4 = 88g/mol

moles of CF4 = 176g ÷ 88g/mol

moles of CF4 = 2mol

No. of molecules = 2 × 6.02 × 10²³

no. of molecules = 12.04 × 10²³

no. of molecules = 1.204 × 10²⁴

Therefore, there are 1.204 × 10²⁴ molecules of carbon tetrafluoride in 176 grams of CF4.

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i killed someone now what?? police are surrounding my house im hiding in my closet i don't know why im on this app but maybe i can get some help cause it isn't a joke

Answers

what’s your address i’ll send the police to help you

When doing the experiment where you compress the air in the syringe, you are collecting 5 data points. Each time you are to decrease the volume by _____ mL

Answers

This question is incomplete, the missing diagram is uploaded along this question below.

Answer:

Each time you are to decrease the volume by 4 mL

Explanation:

From the image, we can see that the volumes of each syringes are displayed;

the first syringe reads 22

the second  syringe reads 18

the third syringe reads 14

the fourth syringe reads 10

and the fifth syringe reads 6

Thus, if we notice the consecutive reading on the syringes, we will notice that each successive step reduces the volume by 4 mL

Therefore, Each time you are to decrease the volume by 4 mL

37.4 g of aluminum chloride reacts with bromine gas to yield aluminum bromide and chlorine gas. How many liters of bromine gas is needed to completely react with aluminum chloride? Assume both gases are at STP.

Answers

Answer:

9.43 L Br₂ (g)

Explanation:

First, write a balanced reaction equation. Then use dimensional analysis to convert from grams of aluminum chloride to moles of aluminum chloride (with molar mass from the periodic table), from moles of aluminum chloride to moles of bromine gas (using the balanced equation), and from moles of bromine gas to liters of bromine gas (remember at STP, 1 mol = 22.4 L). See the attached image for the work out. Finally, account for sig figs to get 9.43 L of bromine gas

If 0.8675 g of KHP requires 24.56 mL of an NaOH solution to reach the equivalence
point in the titration, what is the concentration of the NaOH?

Answers

Answer:

[tex]M_{base}=0.173M[/tex]

Explanation:

Hello there!

In this case, since the titration of acids like KHP with bases like NaOH are performed in a 1:1 mole ratio, it is possible for us to know that their moles are the same at the equivalence point, and the concentration, volume and moles are related as follows:

[tex]n_{acid}=M_{base}V_{base}[/tex]

Thus, by solving for the volume of the base as NaOH, we obtain:

[tex]M_{base}=\frac{n_{acid}}{V_{base}} \\\\M_{base}=\frac{0.8675g*\frac{1mol}{204.22g} }{0.02456L} \\\\M_{base}=0.173M[/tex]

Best regards!

Question 6 of 30 Carbon dioxide subliming is an example of which of the following?​

Answers

Answer:

dry ice or solid carbon(iv)oxide

Explanation:

carbon(iv)oxide that sublimes is known as dry ice or solid CO2 and it is used to refrigerate food instead of ordinary ice which will just melt when exposed to hot conditions and there4 will lead to the destruction of food. dry ice will sublime the moisture from the food there4 keeping out any moisture

giving brainliest!
links=reported

Answers

Answer:

C₃H₈O

Explanation:

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

Mass of Carbon (C) = 0.599 g

Mass of Hydrogen (H) = 0.134 g

Mass of Oxygen (O) = 0.266 g

Empirical formula =?

The empirical formula of the compound can be obtained as follow:

C = 0.599 g

H = 0.134 g

O = 0.266 g

Divide by their molar mass

C = 0.599 / 12 = 0.050

H = 0.134 / 1 = 0.134

O = 0.266 / 16 = 0.017

Divide by the smallest

C = 0.050 / 0.017 = 3

H = 0.134 / 0.017 = 8

O = 0.017 / 0.017 = 1

Empirical formula => C₃H₈O

Which process directly moves nutrients from plants to animals?
A. Feeding
B. Breathing
C. Photosynthesis
D. Mineralization

Answers

Answer:

Dude its A.Feeding

Explanation:

Its common scene that when u eat you are getting nutrient directly from the food. Come on Sponge Bob Me Boy

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