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.
Answers
Answer:
A system absorbs more energy than it releases and has a positive AH
Explanation:
Answer:
Explanation:
Endothermic (endo = into + thermic = heat) means that heat energy is going into a system.
The products will have more energy than the reactants and ΔH will be positive.
A is wrong, because ΔH is positive.
C and D are wrong, because the system absorbs more energy than it releases.
Related Questions
The Ka of acetic acid (CH3COOH) is 1.8 x10-5.
Calculate the pH of a 3.0 M solution of acetic acid.
Answers
Answer: 2.13
Explanation: i crawled so you could run :)
Give the molecular geometry and number of electron groups for sf4. give the molecular geometry and number of electron groups for . square planar, 6 electron groups square pyramidal, 6 electron groups t-shaped, 5 electron groups octahedral, 6 electron groups seesaw, 5 electron groups
Answers
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.
Why might you have difficulty determining the pH of bleach using ph strips?
Answers
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.
Which statements describe gridlines on a map? Select three options. They are measured in degrees. They set up a reference system. They make straight lines on a globe. They run north to west and south to east. They divide Earth into four equal parts.
Answers
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
PLEASE ANSWER ASAP- 2 MIN LEFT
A pH of 7 indicates that a solution is ___________ ; a ph <7 would mean the solution is ____________________; and a pH >7 is a(n) ---------- solution.
Answers
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.
Which statements describe prominences? Check all that apply.
Prominences are dark, cool areas on the surface of the Sun.
Prominences are composed of cool, dense gas.
Prominences can disturb radio communications on Earth.
Prominences cycle over an 11-year period.
Prominences are loop shaped.
Prominences appear in groups.
Answers
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:
Which phrase describes a volcano that is not expected to erupt again?
quiet volcano
extinct volcano
dormant volcano
explosive volcano
Answers
Calculate the hyrdrogen ion concentration [h+] for the aquesous solution in which [oh-] is 1 x 10-2 mol/l.Is the solution acidic,basic,or neutral? Show your work
Answers
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.
water is a highly polar molecule with strong hydrogen bonding. one of the results of this is that water can climb up a narrow tube. the phenomenom is known as:
A. catapult action (aka trebuchet onfire)
B. capillary action
C. carpel tunnel syndrom
D. capitalization
Answers
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
PLEASE HELP
Consider the chemical equations shown here.
3 equations. 1: upper N upper O gas plus upper O subscript 3 gas right arrow upper N upper O subscript 2 gas plus upper O subscript 2 gas. Delta H subscript 1 equals 198.9 kilojoules. 2: StartFraction 3 over 2 EndFraction upper O gas right arrow upper O subscript 3 gas. Delta H subscript 2 equals 142.3 kilojoules. 3: upper O gas right arrow one half upper O subscript 2 gas. Delta H subscript 3 equals negative 247.5 kilojoules.
What is DeltaHrxn for the reaction shown below?
NO(g)+O(g)->NO2(g)
Answers
Answer:
-304.1
I had this question and that’s what I got
Answer:
-867.7
Explanation:
yeah
How many copper atoms are in a 70g copper
Answers
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
I need help. Please give a detailed answer:
Hydrogen cyanide (HCN) is a colorless gas. It is poisonous and smells like almonds. Draw a Lewis structure for this compound, explain why you drew the Lewis structure the way that you did, and predict the shape of the molecule.
Answers
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.
ionic compounds conduct electricity in the solid state true or false
Answers
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.
(Multiple Choice, 30 pts)
A student thinks that halogens are highly reactive because their electrons are weakly attracted to their nuclei. Which is evidence that disputes this student's idea?
A. Halogens react with alkali metals.
B. Halogens cannot react with noble gases.
C. Halogens tend to attract electrons when bonding.
D. Halogens have a full octet of electrons.
Answers
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:
How many moles are in 100g of carbon dioxide?
A.2.27 mol
B.3.51 mol
C. 2.36 mol
D. 1.49 mol
Answers
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!
What are the four main parts of the Sun? *
Answers
Answer: The inner layers are core, radiative zone, and convective zone. The putter layers a photosphere, the chromosphere, the transition region and the corona
Particles of the substance have the most kinetic energy when the substance is(a)_______. The part of the graph that represents where the substance has the least amount of potential energy is labeled(b)_______.
multiple choice answers available.
(a)
1. A gas
2. A solid
3. Melting
4. vaporizing
(b)
1. Solid
2. Vaporizing
3. melting
4.liquid
5.gas
Answers
Answer: 1- gas 2- solid
Explanation:
how many number of electrons are in nitrogen and aluminium in their ionic States?
Answers
And each group (column) after that countdown to zero charge, once you have zero charge you know that you’re in the noble gases.
So, nitrogen in group (column) 15, also know as column 5A. This column has for the most part a charge of -3.
Aluminum is in group (column) 13, they have a charge of +3 typically.
I hope that helps.
If O2(g) reacts with H2(g) to produce H2O, what is the volume of H2O obtained from 1 L of O2?
Hint: Write a balanced equation first!
Answers
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.
A 0.80 L sample of gas has a temperature of 27°C and a pressure of 0.925 atm. How many moles of gas are present?
Answers
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
En la reacción I2(g) + Br2(g) « 2 IBr(g), Keq = 280 a 150°C. Suponga que se permite que 0.500 mol de IBr en un matraz de 1.00 L alcancen el equilibrio a 150°C. ¿Cuáles son las presiones parciales de equilibrio de IBr, I2 y Br2?
Answers
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.
Gas Laws
Assignment Active
Applying Gas Laws to Aerosol Can D
(国座
Explain why it is not a good idea to throw an
aerosol can into a fire. Which gas law applies?
DONE
Answers
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.
C2H6O(g) + 3O2(g) 2CO2(g) + 3H2O(g) Inside the piston of an automobile engine, 0.461 g of ethanol (C2H6O) gas reacts with 0.640 grams of oxygen gas to produce carbon dioxide and water, according to the balanced equation shown above. What is the limiting reagent?
Answers
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:
C: 12 g/moleH: 1 g/moleO: 16 g/molethe molar mass of each reagent is:
C₂H₆O: 2*12 g/mole + 6* 1 g/mole + 16 g/mole= 46 g/moleO₂: 2*16 g/mole= 32 g/moleThen, since 1 mol of C₂H₆O and 3 moles of O₂ react by stoichiometry, the amount of mass that reacts is:
C₂H₆O: 1 mole* 46 g/mole= 46 gO₂: 3* 32 g/mole= 96 gNow 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.
A group of tissues working together is?
Answers
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.
Which of the following Noble Gases has a mass of 10.0 g?
Answers
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:
Which statement describes a gas condensing into a liquid?
A.
The atoms in the molecules get heavier so they move less.
B.
The molecules break into smaller pieces that take up less space.
C.
The molecules stick together to make bigger molecules.
D.
The molecules get closer together and move more slowly.
Answers
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.
PLEASE HURRY
Which substance loses electrons in a chemical reaction?
A.the one that is oxidized, which is the oxidizing agent
B.the one that is reduced, which is the reducing agent
C.the one that is oxidized, which is the reducing agent
D.the one that is reduced, which is the oxidizing agent
Answers
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:
Molecules have Question 1 options: A) both potential and kinetic energy. B) neither kinetic nor potential energy. C) only kinetic energy. D) only potential energy.
Answers
Answer:A
Explanation:
Answer: A
Explanation:
According to one acid-base theory a molecule acts as an acid when the molecule
Answers
What is frequency and what unit is it measured in?
Answers
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:
