Which one is it for a brialiest
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.
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!
What would you call the bright blue liquid?
PLEASE HELP!!!!!!!
Answer:
2nd option
Explanation:
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.
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.
What keeps the Earth orbiting on its current path
in our solar system?
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?
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
different between intermolecular and intra molecular dehydration
Answer: Intermolecular bonds are the forces between the molecules. Intramolecular are the forces within two atoms in a molecule.
Explanation:
The iodide in a sample that also contained chloride was converted to iodate by treatment with an excess of bromine: The unused bromine was removed by boiling; an excess of barium ion was then added to precipitate the iodate: In the analysis of a 1.54-g sample, 0.0596 g of barium iodate was recovered. Express the results of this analysis as percent potassium iodide.
Answer: The percentage of potassium iodide in the sample is 2.63 %.
Explanation:
The chemical equation for the reaction of iodide ions with bromine gas follows:
[tex]I^-+3Br_2+3H_2O\rightarrow 6Br^-+IO_3^-+6H^+[/tex] (i)
The chemical equation for the reaction of iodate ions with barium ions follows:
[tex]Ba^{2+}+2IO_3^-\rightarrow Ba(IO_3)_2[/tex] ......(ii)
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of barium iodate = 0.0596 g
Molar mass of barium iodate = 487.13 g/mol
Using equation 1:
[tex]\text{Moles of barium iodate}=\frac{0.0596 g}{487.13 g/mol}\\\\\text{Moles of barium iodate}=1.22\times 10^{-4} moles[/tex]
By Stoichiometry of the reaction (ii):
1 mole of barium iodate is produced by 2 moles of iodate ions
So, [tex]1.22\times 10^{-4} moles[/tex] of barium iodate will be produced by [tex]\frac{2}{1}\times 1.22\times 10^{-4} =2.44\times 10^{-4}moles[/tex] of iodate ions
By the stoichiometry of the reaction (i):
1 mole of iodate ions are produced by 1 moles of iodine ions
So, [tex]2.44\times 10^{-4} moles[/tex] of iodate ions will be produced by [tex]\frac{1}{1}\times 2.44\times 10^{-4} =2.44\times 10^{-4}moles[/tex] of iodine ions
Moles of potassium iodide = Moles of iodide ions = [tex]2.44\times 10^{-4}[/tex]
Since, the molar mass of potassium iodide = 166 g/mol
Using equation 1:
[tex]\text{Mass of potassium iodide}=2.44\times 10^{-4}mol\times 166 g/mol\\\\\text{Mass of potassium iodide}=0.0405 g[/tex]
To calculate the percentage by mass of a substance, the equation used is:
[tex]\text{Percent by mass}=\frac{\text{Mass of a substance}}{\text{Mass of solution}}\times 100[/tex]
Mass of a solution = 1.54 g
Mass of potassium iodide = 0.0405 g
Using above equation:
[tex]\text{Percent potassium iodide}=\frac{0.0405 g}{1.54g}\times 100\\\\\text{Percent potassium iodide}=2.63\%[/tex]
Hence, the percentage of potassium iodide in the sample is 2.63 %.
Expressing the results of potassium iodide in percentage = 2.63%
The chemical reaction of iodine ions with Bromine gas can be expressed as :
I⁻ + 3Br₂ + 3H₂O -- > 6Br⁻ + IO₃ + 6H⁺ ----- ( 1 )
Chemical reaction between iodate ions with barium ions can be expressed as : Ba²⁺ + 2IO⁻₃ ------> Ba ( IO₃ )₂ --------- ( 2 )
Step 1 : Calculate the number of Barium iodate moles
mass of Barium iodate = 0.0596 g
molar mass of Barium iodate = 487.13 g/mol
from equation ( 1 )
moles of Barium iodate = ( 0.0596 ) / ( 487.13 ) = 1.22 * 10⁻⁴ moles
also from equation ( 1 ) the moles of potassium iodide = moles of iodide ions
= 2.44 * 10⁻⁴
molar mass of potassium iodide = 166 g/mol
Next step : Determine the mass of potassium iodide
moles of potassium * molar mass
= 2.44 * 10⁻⁴ * 166 g/mol = 0.0405 g
Final step : Determine the percentage of potassium iodide in the solution
Percentage = ( mass of potassium iodide / mass of solution ) * 100
= ( 0.0405 / 1.54 ) * 100
= 2.63%
Hence we can conclude that potassium iodide in percentage = 2.63%
Learn more : https://brainly.com/question/3388761
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.
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.
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.
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:
https://brainly.com/question/3393755
#SPJ3
What is the source of Earth's magnetic field according to what you have read in chapter 222
Answer:
Scientists know that today the Earth's magnetic field is powered by the solidification of the planet's liquid iron core. The cooling and crystallization of the core stirs up the surrounding liquid iron, creating powerful electric currents that generate a magnetic field stretching far out into space.
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.
It is about 3.86 which is 10⁶⁶ watts
Answer:
410 quintillion Joules or 430,000,000,000,000,000,000 Joules
Atoms of which elements form bonds without satisfying the octet rule?
Answer:
Helium and hydrogen......
A car generates 2552 N and weighs 2250 kg. What is its rate of acceleration
2 m/s ^2
0.88m/s^2
5,742,000m/s^2
1.13m/s^2
Answer:
[tex]a=1.134\frac{m}{s^2}[/tex]
Explanation:
Hello there!
In this case, by considering the physical definition of force in terms of mass and acceleration:
[tex]F=m*a[/tex]
Given the generated force and the involved mass, we can compute the required acceleration as shown below:
[tex]a=\frac{F}{m}\\\\a=\frac{2552N}{114kg}[/tex]
Yet it is necessary to break out Newtons to:
[tex]a=\frac{2552\frac{kg*m}{s^2} }{114kg}\\\\a=1.134\frac{m}{s^2}[/tex]
Best regards!
Which of the following must be overcome by a rocket's thrust?
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 :)
visible light travels from place to place as a
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:
1. (An example of non-point-source pollution is
A. Wastewater from a leaking pipe.
B. Fertilizer runoff from lawns.
C. Oil from a leaking underground tank.
D. Chemicals released from a paper mill
Answer:
i think the answer is c.
Explanation:
is sublimation a chemical change or chemical property or physical change?
Answer:
Physical Change
Explanation:
Sublimation is a physical change. When a substance sublimes, it changes from a solid to a gas without going through the liquid phase.
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!
Answer: a.) Methyl would be the answer.
Explanation:
. 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
As mentioned in the kinetic molecular theory, what is the main reason that the volume of gas particles can be considered zero?
a)The bonds present in gas particles are stronger than other bonds, pulling atoms in closer to each other, causing a shorter bond length which greatly decreases the volume.
b)When atoms enter the gas phase, they are less affected by gravity, which lowers their mass and in turn, their volume.
c)The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained.
Answer:
The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained
Explanation:
Which of the following forces has the smallest energy per bond?
A) iconic bonds
B) covalent bonds
C) hydrogen bonds
D) dispersion bonds
......A) iconic bonds........
The attractive forces existing between the molecules of a substance are known as the intermolecular forces. Among the given forces dispersion bonds has the smallest energy per bond. Thus option D is correct.
What is Dispersion forces?The forces which are found in nonpolar molecules like O₂, N₂, Cl₂ etc. as well as in monoatomic gases such as 'He', 'Ne' etc. are called dispersion forces or London forces.
The London force is found to be the weakest intermolecular force and it is known to operate in all types of molecules. This force is also called the induced dipole - induced dipole attraction.
This force is generally resulted from the movement of electron cloud which creates a temporary instantaneous dipole. This distorts the arrangement of electrons of other atoms or molecules which are close to it and also induces a dipole in them.
In this way a large number of nonpolar molecules become polar temporarily and they are attracted by weak attractive forces. The dispersion bonds are easy to form and break.
The dispersion force is the weak attractive force and has the smallest energy per bond.
Thus the correct option is D - Dispersion bonds.
To know more about the dispersion bonds, visit;
https://brainly.com/question/30402657
#SPJ6
Compare Dalton’s and Democritus’ ideas.
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.
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.
A. High energy radiation produced in the ozone layer. (:
A 0.10M NH3 solution is 1.3% ionized, calculate the hydrogen ion concentration
Answer:NH3 + H2O <==> NH4+ + OH-
0.10 x 0.013 = 0.0013 M (this is the hydroxide concentration)
Kw = [H+] [H-]
1.00 x 10^-14 = (x) (0.0013)
x = 7.7 x 10^-12 M
Explanation:
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 ________ ____________.
Answer:
EliminationEliminationZaitsevZaitsevCarbocationExplanation:
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 CARBOCATIONElimination 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:
https://brainly.com/question/10099008
When NH3(g) reacts with O2(g) to form N2O(g) and H2O(l), 342 kJ of energy are evolved for each mole of NH3(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation.
Answer: [tex]2NH_3(g)+2O_2(g)\rightarrow N_2O(g)+3H_2O(l)+684kJ[/tex]
Explanation:
The skeletal thermochemical equation for the reaction is:
[tex]NH_3(g)+O_2(g)\rightarrow N_2O(g)+H_2O(l)+342kJ[/tex]
The balanced thermochemical equation for the reaction is:
[tex]2NH_3(g)+2O_2(g)\rightarrow N_2O(g)+3H_2O(l)+684kJ[/tex]
When 1 mole of [tex]NH_3[/tex] reacts with oxygen , heat released = 342 kJ
Thus when 2 moles of [tex]NH_3[/tex] reacts with oxygen , heat released = [tex]\frac{2}{1}\times 342 kJ=684kJ[/tex]
which bond does water atom share
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.
Nitric oxide (NO) reacts with oxygen gas to produce nitrogen dioxide. A gaseous mixture contains 0.66 g of nitric oxide and 0.58 g of oxygen gas. After the reaction is complete, what mass of nitrogen dioxide is formed? Which reactant is in excess? How do you know? Suppose you actually recovered 0.91 g of nitrogen dioxide. What is your percent yield?
Answer:
NO is the limiting reagent.
In this reaction 0.886 mole of NO2 is produced
Explanation:
The chemical equation for this reaction is
2NO(g) + O2(g) → 2NO2(g)
In this limiting reagent reaction, 2 moles of NO reacts with one mole of O2 to produce 2 mole of 2NO2
0.886 mole of NO * (2 mole of NO2/2 mole of NO) = 0.886 mole of NO2
0.503 mole of O2 * (1 mole of NO2/1 mole of O2) = 1.01 mole of NO2
Hence, NO is the limiting reagent.
In this reaction 0.886 mole of NO2 is produced