Which of these is true concerning an endothermic reaction? *
When a system absorbs more energy than it releases and has a negative AH.
When a system absorbs more energy than it releases and has a positive AH.
When a system releases more energy than it absorbs and has a negative AH.
When a system releases more energy than it absorbs and has a positive AH.

Answer:

B. Prominences are composed of cool, dense gas.

C. Prominences can disturb radio communications on Earth.

D. Prominences cycle over an 11-year period.

E. Prominences are loop shaped.

Explanation:

Prominence is the release of high energy particles or dense gases in the form of a loop shape from the surface of the sun. It is cooler and flows out into the Sun's hot atmosphere known as corona.

Once formed, prominence can be quiescent in the space for some period of time before it erupt and get ejected. This eruption and ejection can lead to coronal mass ejections which extends over a very long distance.

When compared to the Sun's temperature, prominences are cooler.

Answer:

B C E

Explanation:

Answer:

5 electron groups, see saw

Explanation:

During the formation of SF4, the sulfur atom usually bonds with each of four fluorine atoms where 8 of valence electrons are used. The four fluorine atoms have 3 lone pairs of electrons in its octet which will further utilize 24 valence electrons. In addition, two electrons are present as a lone pair on the sulfur atom. We can determine sulfur’s hybridization state by counting of the number of regions of electron density on sulphur (the central atom in the molecule). When bonding takes place there is a formation of 4 single bonds to sulfur and it has 1 lone pair. Looking at this, we can say that the number of regions of electron density is 5. The hybridization state is sp3d.

SF4 molecular geometry is seesaw with one pair of valence electrons. The molecule is polar. The equatorial fluorine atoms have 102° bond angles instead of the actual 120° angle. The axial fluorine atom angle is 173° instead of the actual 180° bond angle.

Answer:

Option B is correct.

0.119 mole of Kr has a mass of 10.0 g

Explanation:

The complete Question was ontained online, albeit, it was incomplete, even from the online source. But the solution is possible based on the part of the question obtained.

Complete Question

Which of the following Noble Gases has a mass of 10.0 g?

A. 2.02 mol Ne B. 0.119 mol Kr C.

Solution

Number of moles = (Mass)/(Molar Mass)

Mass = (Number of moles) × (Molar mass)

Checking the options, one at a time,

A. 2.02 moles of Neon

Number of moles = 2.02 moles

Molar Mass of Neon = 20.1797 g/mol

Mass = 2.02 × 20.1797 = 40.762994 g ≠ 10.0 g

Not the answer.

B. 0.119 moles of Krypton

Number of moles = 0.119 moles

Molar Mass of Krypton = 83.798 g/mol

Mass = 0.119 × 83.798 = 9.971962 g ≈ 10.0 g

This is definitely the answer.

Hope this Helps!!!

Answer: 0.119 mol Kr

Explanation:

Answer:A

Explanation:

Answer: A

Explanation:

In solid form, ionic compounds do not conduct electricity. Ionic compounds will conduct electricity when melted to their liquid state. This is due to the electrons being locked in place when in solid form, but liquid form allows for the electrons to move freely.

Answer:

P IBr: 15.454atm

I₂: 0.923 atm

P Br₂: 0.923atm

Explanation:

Basados en la reacción:

I₂(g) + Br₂(g) ⇄ 2 IBr(g)

La constante de equilibrio, Keq, es definida como:

[tex]Keq = \frac{P_{IBr}^2}{P_{I_2}P_{Br_2}}[/tex]

Se cumple la relación de Keq = 280 cuando las presiones están en equilibrio

Usando PV = nRT, la presión inicial de IBr es:

P = nRT / V; 0.500mol*0.082atmL/molK*423.15K / 1.00L = 17.3 atm

Siendo las presiones en equilibrio:

P IBr: 17.3 - 2X

P I₂: X

P Br₂: X

Donde X representa el avance de reacción.

Remplazando en Keq:

280 = (17.3 - 2X)² / X²

280X² = 4X² - 69.2X + 299.29

0 = -276X² - 69.2X + 299.29

Resolviendo para X:

X = -1.174 → Solución falsa. No existen presiones negativas

X = 0.923 → Solución real

Así, las presiones parciales en equilibrio de cada compuesto son:

P IBr: 17.3 - 2X = 15.454atm

P I₂: X = 0.923atm

P Br₂: X = 0.923atm

Answer:

[tex]p_{I_2}=0.926atm\\p_{Br_2}=0.926atm\\p_{IBr}=15.5atm[/tex]

Explanation:

Hello,

In this case, given the initial load of 0.500 mol of IBr in the 1.00-L, we compute its initial concentration:

[tex][IBr]_0=\frac{0.500mol}{1.00L}=0.500M[/tex]

Hence, by knowing the original reaction, we should invert it as IBr will produce iodine and bromine considering the initial load:

[tex]2IBr(g)\rightleftharpoons I_2(g) + Br_2(g)[/tex]

Therefore, the equilibrium constant should be inverted:

[tex]K'=\frac{1}{Keq}=\frac{1}{280}=3.57x10^{-3}[/tex]

So we write the law of mass action:

[tex]K'=\frac{[I_2][Br_2]}{[IBr]^2}[/tex]

That in terms of the change [tex]x[/tex] due to the reaction extent turns out:[tex]3.57x10^{-3}=\frac{(x)(x)}{(0.500-2x)^2}[/tex]

In such a way, solving by using solver or quadratic equation we obtain:

[tex]x_1=-0.0339M\\x_2=0.0267M[/tex]

Clearly, the solution is 0.0267M, thus, the equilibrium concentrations are:

[tex][I_2]=x=0.0267M[/tex]

[tex][Br_2]=x=0.0267M[/tex]

[tex][IBr]=0.5M-2x=0.5M-2*0.0267M=0.447M[/tex]

Thus, with the given temperature (150+273.15=423.15K), we compute the partial pressures by using the ideal gas equation:

[tex]p_{I_2}=[I_2]RT=0.0267\frac{mol}{L} *0.082\frac{atm*L}{mol*K}*423.15K\\\\p_{I_2}=0.926atm\\\\p_{Br_2}=[Br_2]RT=0.0267\frac{mol}{L} *0.082\frac{atm*L}{mol*K}*423.15K\\\\p_{Br_2}=0.926atm\\\\p_{IBr}=[IBr]RT=0.447\frac{mol}{L} *0.082\frac{atm*L}{mol*K}*423.15K\\\\p_{IBr}=15.5atm[/tex]

Best regards.

Answer:

-304.1

I had this question and that’s what I got

Answer:

-867.7

Explanation:

yeah

Answer: 1- gas 2- solid

Explanation:

Answer: 2.13

Explanation: i crawled so you could run :)

Answer: The inner layers are core, radiative zone, and convective zone. The putter layers a photosphere, the chromosphere, the transition region and the corona

Answer:

Oxygen is the limiting reactant.

Explanation:

Hello,

In this case, given the reaction:

[tex]C_2H_6O(g) + 3O_2(g)\rightarrow 2CO_2(g) + 3H_2O(g)[/tex]

Hence, given the masses of both ethanol and oxygen, we are able to compute the available moles ethanol by:

[tex]n_{C_2H_6O}^{available}=0.461g*\frac{1mol}{46g}=0.01mol C_2H_6O[/tex]

Next, we compute the moles of ethanol that react with the 0.640 grams of oxygen considering their 1:3 molar ratio in the chemical reaction:

[tex]n_{C_2H_6O}^{consumed\ by\ O_2}=0.64gO_2*\frac{1molO_2}{32gO_2}*\frac{1molC_2H_6O}{3molO_2} =0.0067molC_2H_6O[/tex]

In such a way, since there are 0.01 available moles of ethanol but just 0.0067 moles are reacting, we evidence ethanol is in excess, therefore the oxygen is the limiting reactant.

Best regards.

Answer:

Oxygen O₂ will be the limiting reagent.

Explanation:

C₂H₆O(g) + 3 O₂(g) ⇒ 2 CO₂(g) + 3 H₂O(g)

First of all you must know by stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction) how much mass of each compound reacts. First of all, being:

the molar mass of each reagent is:

Then, since 1 mol of C₂H₆O and 3 moles of O₂ react by stoichiometry, the amount of mass that reacts is:

Now you apply a rule of three as follows: if 46 g of C₂H₆O reacts with 96 g of O₂ by stoichiometry, 0.461 g of C₂H₆O with how much mass of O₂ will they react?

[tex]mass of O_{2} =\frac{0.461 grams of C_{2}H_{6} O*96 grams ofO_{2} }{46 grams of C_{2}H_{6} O}[/tex]

mass of O₂= 0.962 grams

But 0.962 grams of O₂ are not available, 0.640 grams are available. Since you have less mass than you need to react with 0.461 g of C₂H₆O, oxygen O₂ will be the limiting reagent.

Answer: molecules get closer

Explanation:

Condensation is the process in which molecules of a gas slow down, come together, and form a liquid. When gas molecules transfer their energy to something cooler, they slow down and their attractions cause them to bond to become a liquid

hope this helps

pls mark me brainliest

Answer:

D. The molecules get closer together and move more slowly.

Answer:

Option B, Capillary action

Explanation:

Water molecules attach with the molecules of the surface of the container in which they are kept. This is because of the cohesive force within the molecules of water and adhesive force between the molecules of water and other substances.

The water rises up in a capillary tube because of water molecules adhere at the edges thereby creating a meniscus in the upside turned direction. The surface is kept intact by the surface tension

Now capillary action specifically occurs when adhesion to the surface of the container is higher than the cohesion between the water molecules.  

Hence, option B is correct

Answer:

2L

Explanation:

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

2H2 + O2 —> 2H2O

1 mole of a gas occupy 22.4L.

1 mole of O2 occupy 22.4L.

2 moles of H2O occupy = 2 x 22.4 = 44.8L.

From the balanced equation above,

22.4L of O2 produced 44.8L of H2O.

Therefore, 1L of O2 will produce = 44.8/22.4 = 2L.

Therefore, 1L of O2 will produce 2L of H2O.

Answer:

An organ

Explanation:

An organ is one or more tissues that work together to form a specific function.

- Hope that helps! Please let me know if you need further explanation.

Answer: The rate at which a vibration occurs that constitutes a wave, either in a material (as in sound waves), or in an electromagnetic field (as in radio waves and light), usually measured per second. Also it is measured in Hertz.

Explanation:

Answer frequency is the number of occurrences of a repeating event per unit of time. Frequency is measured in Hertz. Unit frequency is measured as the number of wave cycles that occur in one second.

The unit of frequency measurement is hertz

Explanation:

Answer:

Ideal Gas Law

PV = nRT

Explanation:

Pressure is proportional to temperature;

The heat of the fire would cause increased pressure inside the closed aerosol vessel, eventually resulting in explosion of the vessel, once the temperature rises enough.

Answer:

neutral, acidic, basic

Explanation:

Know the acidity rules. Sorry I just saw this!

- Hope that helps! Please let me know if you need further explanation.

Answer:

What ever you want. I made it like this because it would make the most logical sense with a mix of the Dot system.

Explanation:

Since the question says to explain yourself, and to predict, really any answer would be correct since it sounds like it's not asking for a correct answer, but more of an answer that would make sense to you and explain it. That's really what chemistry is, a bunch of educated responses and guesses with confidence.

Answer:

n= 0.03 moles

Explanation:

Using the ideal gas law:

PV=nRT

nRT=PV

n= PV/RT

 n: moles

 P: pressure in atm

 V= volume in L

 R= Avogadro's constant = 0.0821

 T= Temperature in K => ºC+273.15

n= (0.925 atm)(0.80 L) / (0.0821)(300.15 K)

n= 0.03 moles

Answer:

[tex]x = 6.634\times 10^{23}\,atoms[/tex]

Explanation:

The quantity of atoms within the mass of copper is determined by multiplying the quantity of moles by the Avogadro's Number:

[tex]x = \left(\frac{70\,g}{63.546\,\frac{g}{mol}} \right)\cdot \left(6.022\times 10^{23}\,\frac{atoms}{mol} \right)[/tex]

[tex]x = 6.634\times 10^{23}\,atoms[/tex]

Answer:

6.64x10^23 atoms.

Explanation:

From Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This implies that 1 mole of Cu also contains 6.02x10^23 atoms.

1 mole of Cu = 63.5g

If 63.5g of Cu contains 6.02x10^23 atoms,

Then 70g of Cu will contain = (70x6.02x10^23) /63.5 = 6.64x10^23 atoms.

Therefore, there are 6.64x10^23 atoms in 70g oh Cu

Answer:

- [tex][H^+]=1x10^{-12}[/tex]

- Basic.

Explanation:

Hello,

In this case, given the concentration of hydroxyl ions, one could compute the pOH as shown below:

[tex]pOH=-log([OH^-])=pOH=-log(1x10^{-2})=2[/tex]

Then, since the pOH and the pH are related by:

[tex]pH+pOH=14[/tex]

One computes the pH:

[tex]pH=14-pOH=14-2=12[/tex]

Now, we compute the concentration of hydronium by:

[tex][H^+]=10^{-pH}=10^{-12}[/tex]

[tex][H^+]=1x10^{-12}[/tex]

Finally, since the pH is greater than 7 (neutral point) we conclude that the solution is basic.

Best regards.

Answer:

A. Hydrogen ion concentration, [H+] is 1x10^–12 mol/L

B. Since the pH is 12, the solution is basic.

Explanation:

Data obtained from the question. This includes the following:

Concentration of Hydroxide ion, [OH-] = 1x10^–2 mol/L

Concentration of Hydrogen ion, [H+] =.?

pH =..?

A. Determination of the hydrogen ion concentration, [H+] .

The hydrogen ion concentration, [H+] can be obtained as follow:

[H+] x [OH-] = 1x10^–14

[OH-] = 1x10^–2

[H+] x 1x10^–2 = 1x10^–14

Divide both side by 1x10^–2

[H+] = 1x10^–14 / 1x10^–2

[H+] = 1x10^–12 mol/L

B. Determination of the pH of the solution.

The pH of the solution can be obtained as follow:

pH = –Log [H+]

[H+] = 1x10^–12 mol/L

pH = –Log 1x10^–12

pH = 12.

Then pH of a solution ranges between 0 and 14.

A pH reading between 0 and 6 is termed an acidic solution, a pH reading of 7 is termed a neutral solution and a pH reading between 8 and 14 indicates an alkaline or a basic solution.

The higher the pH value, the more alkaline or basic the solution becomes.

Since the pH is 12, the solution is basic.

Answer:

4) the one that is reduced, which is the oxidizing agent

Explanation:

An oxidizing agent is one that causes oxidation by gaining electrons from another atom/molecule.

Answer:

c

Explanation:

Answer:

The options that apply to the description of grid-lines of the map are;

They are measured in degrees

They set up a reference system

They divide Earth into four equal parts

FIRST OPTION , SECOND OPTION and FIFTH OPTION are correct.

Explanation:

FIRST OPTION gave the describtion that the grid-lines of the map are measure in degrees,this option is applied to the gridlines on a map because the grid are lined as a result of angular measurement which makes it to makes the unit to be measured degrees and angles.

SECOND OPTION described it as been set up by a reference system which let us know that the area that are plotted were all grid as a result of the size

FIFTH OPTION also applied to the

description of the gridlines on a map because the Earth is divided into 4 equal parts through the Prime Meridian i.e the latitudinal line and longitudinal line .

.

Answer:

They are measured in degrees.

They set up a reference system.

They divide Earth into four equal parts.

Explanation:

i took the test

Answer:

c

Explanation:

¨Halogens being non metals have greater electronegativities hence, attract electrons and making the statement disputed. Nobel gases are highly stable; this explains why they are nonreactive. They do not form chemical bonds because they only have a little tendency to either gain or lose an electron; on the other hand, halogens are reactive because they only need one additional electron to complete their octet. ¨

i found that from another users answer for the same question

Answer:

answer c

Explanation:

Answer:

A

Explanation:

First, let's find the molar mass of CO₂. This is 12 + 2(16) = 44 g/mole.

Now we can write 100g * (1 mole / 44g) = 2.27 mol, or A. Hope this helps!

Answer:

pH test strips will lose colour and their pH sensitivity as strips are made from universal indicator. Universal indicator is composed of phenolphthalein, methyl red, methyl orange and thymol blue.

Explanation:

pH test strips are made from the universal indicator. The universal indicator is composed of phenolphthalein, methyl red, methyl orange, and thymol blue. All of these will react with chlorine in bleach. As a result, they will lose color and pH sensitivity. Due to this, it is difficult to determine the pH of bleach using ph strips.