Answer:
Heat of sublimation of Li(s) = 160.5 kJ/mol
Explanation:
Given that:
[tex]\mathtt{2Li(s) + \dfrac{1}{2} I_2(g) \to 2LiI(s)}[/tex]
ΔH = –292 kJ
The heat of formation for the above reaction = –292 kJ × 2 = -584 kJ/mol
[tex]\mathtt{Li^+_{(g)} + I^-_{(g)} \to LiI_{(s)}}[/tex]
The lattice energy of LiI(s) = -753 kJ/mol
[tex]\mathtt{Li(g)\to Li^+(g) + e^- }[/tex]
The ionization energy of LiI(s) = +520 kJ/mol
[tex]\mathtt{I_2_{(g)} \to 2I_{(g)} }[/tex]
The Bond Energy of I₂(g) = 151 kJ/mol
[tex]\mathtt{I_{(g)} + e^- \to I^-_{(g)}}[/tex]
The electron affinity of I(g) = -295 kJ/mol
Heat of sublimation: Sublimation is the process of changing of a solid matter into gas without passing through the liquid stage, Now, the molar heat of sublimation is the amount of energy that must be added to a mole of solid to turn it directly into a gas without any interference through the liquid phase provided the pressure is constant.
From the above reactions: The heat of sublimation of Li(s) can be calculated by the sum total of the following.
[tex]\mathtt{Li_{(s)} + \dfrac{1}{2} I_2_{(g)} \to LiI_{(s)} \ \ -292 kJ/mol} \\ \\\mathtt{I_{(g)} \to \dfrac{1}{2} I2(g) \ \ -75.5 kJ/mol} \\ \\ \mathtt{I^-(g) \to I(g) + e^- \ \ +295 kJ/mol} \\ \\ \mathtt{LiI(s) \to Li^+_{(g)} + I^-_{(g)} \ \ +753 kJ/mol} \\ \\ \mathtt{Li^+_{(g)} + e^- \to Li(s) \ \ -520 kJ/mol} \\ \\[/tex]
[tex]\mathtt{Li(s) \to Li(g)}[/tex] = (-292 +(-75.5)+295+753+(-520)) kJ/mol
[tex]\mathtt{Li(s) \to Li(g)}[/tex] = 160.5 kJ/mol
Heat of sublimation of Li(s) = 160.5 kJ/mol
I'll GIVE BRAINLIEST: In a redox reaction, CO is changed to CO2. How many electrons must be lost or gained by C and why?
Answer:
C is gaining 2 electrons
Explanation:
O has a 2- charge so for CO to pick up another O atom would add 2 more electrons.
Answer:
C gains 2 electrons
Explanation:
In the redox reaction, CO is changed into CO2 which means there is an additional oxygen. Oxygen loses 2 of its electrons in order to neutralize. So, C must be gaining 2 electrons in order to make the bond.
name of the compound Br8P4
Answer:
4-phospho,Bromooctane
Ag2S + Al(s) = Al2S3 + Ag(s) (unbalanced)
1) What would the overall potential for this cell be?
2) Write the standard cell notation for an electrochemical cell consisting of an anode and cathode of the same types as in this experiment, connected through a salt bridge.
Answer:
1. 0.97 V
2. [tex]Al_(_s_)/Al^+^3~_(_a_q_)~//~Ag^+~_(_a_q_)/Ag_(_s_)[/tex]
Explanation:
In this case, we can start with the half-reactions:
[tex]Ag^+~_(_a_q_)->~Ag_(_s_)[/tex]
[tex]Al_(_s_)~->~Al^+^3~_(_a_q_)[/tex]
With this in mind we can add the electrons:
[tex]Ag^+~_(_a_q_)+~e^-~->~Ag_(_s_)[/tex] Reduction
[tex]Al_(_s_)~->~Al^+^3~_(_a_q_)+~3e^-~[/tex] Oxidation
The reduction potential values for each half-reaction are:
[tex]Ag_2S~+~e^-~->~Ag_(_s_)~+~S^-^2~_(_a_q_)[/tex] - 0.69 V
[tex]Al^+^3~_(_a_q_)+~2e^-~->~Al_(_s_)[/tex] -1.66 V
In the aluminum half-reaction, we have an oxidation reaction, therefore we have to flip the reduction potential value:
[tex]Al_(_s_)~->~Al^+^3~+~2e^-~[/tex] +1.66 V
Finally, to calculate the overall potential we have to add the two values:
1.66 V - 0.69 V = 0.97 V
For the second question, we have to keep in mind that in the cell notation we put the anode (the oxidation half-reaction) in the left and the cathode (the reduction half-reaction) in the right. Additionally, we have to use "//" for the salt bridge, therefore:
[tex]Al_(_s_)/Al^+^3~_(_a_q_)~//~Ag^+~_(_a_q_)/~Ag_(_s_)[/tex]
I hope it helps!
Scientists from different fields are trying to understand how the global climate is reacting to the changes caused in nature, and by human activities. They have come up with conflicting interpretations. Which of these is the most likely outcome of differences in interpretations made by scientists on the issue of global climate?
Answer:
New ideas would be created and tested
Explanation:
All old ideas would be discarded.
Scientific evidence would be weakened.
New ideas would be created and tested.
The limitations of science would be evident.
In science, old ideas are usually improved or modified and not entirely discarded. The old ideas form the basis for new ideas after extensive reviews. Differences in the interpretations made by scientists on any particular phenomenon give rooms for reviews. The reviews often generate new ideas or hypotheses and these can be tested using relevant experimental procedures according to the scientific method.
Hence, the correct answer would be that new ideas would be created and tested.
Examine the given reaction. NH4NO3(s) → NH4+(aq) + NO3–(aq) ΔH° = 25.45 kJ/mol ΔS° = 108.7 J/mol·K Which of the given is correct about the ΔG° at 25 °C?
A)+4,360 J
B)−6,942 J
C)−4,360 J
D)+6,942 J
Answer:
B)−6,942 J /mol
Explanation:
At constant temperature and pressure, you cand define the change in Gibbs free energy, ΔG, as:
ΔG = ΔH - TΔS
Where ΔH is enthalpy, T absolute temperature and ΔS change in entropy.
Replacing (25°C = 273 + 25 = 298K; 25.45kJ/mol = 25450J/mol):
ΔG = ΔH - TΔS
ΔG = 25450J/mol - 298K×108.7J/molK
ΔG = -6942.6J/mol
Right solution is:
B)−6,942 J /molIf the temperature of a gas increased from 100K to 200K and the volume of a gas decreased from 20L to 10L, what is the new pressure I’d the original pressure was 100 kPa?
Answer:
400 kPa
Explanation:
using General Gas Law
[tex] \frac{100 \times 20}{100} = \frac{p \times 10}{200} [/tex]
[tex]p = 400[/tex]
The concept combined gas law is used here to determine the new pressure of the gas. The pressure of the gas obtained is 400 kPa.
What is combined gas law?The equation connecting the volume, pressure and temperature of a gas can be represented mathematically by an equation called the combined gas law. In this equation the temperature should be always in Kelvin.
The combined gas law is also defined as the ideal gas law without Avogadro's law. It is the combination of Boyle's law, Charles's law and Gay-Lussac's law. The equation is given as:
PV/T = k
Here 'P' is the pressure, 'V' is the volume, 'T' is the temperature and 'k' is a constant. The equation for two gases of different volumes and temperature is:
P₁V₁ / T₁ = P₂V₂ / T₂
Then P₂ = P₁V₁T₂ / T₁V₂
Here the new pressure P₂ is:
P₂ = 100 × 20 × 200 / 100 × 10
P₂ = 400 kPa.
Thus the new pressure is 400 kPa.
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Which of the following results in a decrease in the entropy?
Heating ice
Increasing mass
Cooling a liquid
Dissolving salt in water
Answer:
cooling a liquid
Explanation:
Temperature is lowered and the energy of molecules, and therefore number of available configuration , is lowered
The thermal energy present in the system for the product formation is entropy. Cooling a liquid can decrease the entropy of the thermodynamic system. Thus, option C is correct.
What is entropy?Entropy is the energy and the heat present in the reactant of the thermodynamic system that is associated with the randomness and disorder of the particle matter in the reaction system.
Entropy is dependent on factors like dissolution, temperature, randomness, kinetic energy, etc. The entropy increases with an increase in the dissolution and tempearture.
The process of cooling liquid lowers the temperature which in turn decreases the kinetic energy and randomness of the molecules and at last, the entropy decreases.
Therefore, the cooling of the liquid decreases the entropy.
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List down the observations made by Rutherford during the gold foil experiment.
Answer:
1) The volume occupied by an atom is composed of mainly empty space
2) Atoms have a very small, relatively dense, central nucleus that is positively charged
3) The region around the nucleus of an atom are orbited by negatively charged electrons in a the same fashion planets orbit around the Sun.
Explanation:
The selection of gold for the gold foil experiment was due to its ability to be rolled into extremely thin sheets such that it was expected for alpha particle to perforate or pass through the foil.
ХА
19
Which two major parts of the Earth system does this photo most clearly
show?
O A. Atmosphere
B. Biosphere
c. Cryosphere
PREVIOUS
Answer:
B. Biosphere.
Explanation:
Mention the four characterstics of warm blooded animals.
Answer:
The four characrteristics of warm blooded animals are÷
Explanation:
i=They can keep its body temperature the same no matter what the outside temperature .
ii=They can maintain a constant body temperature.
iii=They obtain energy from food consumption.
iv=They maintain their body temperature higher than environment.
Answer:
i) Their body temperature remain constant in any climate.
ii) They obtain energy from food consumption
I only know this much:)
describe how thin layer chromatography is used in the isolation and extraction of lipids
Thin layer chromatography(TLC) works with the principle of separation through adsorption.
It is used in the isolation and extraction of lipids through the following steps:
apply the lipid samples spots in the bottom of the plate.also apply sample solution to the marked spotpour the mobile phase into the TLC chamber and use a moist filter paper to cover it. this is done to maintain equal humidity.then place the plate in the TLC chamber and close it with a lid.the plate is immersed into the solvent (mobile phase) for its development. this is done, keeping in mind that the sample spot should be above the solvent.once the sample spots are developed, they are removed and dried.this is later viewed using the UV light chamber to see the isolation of the lipid sample.Learn more here:
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full form of soil pH
Answer:
PH STANDS FOR POTENTIAL OF HYDROGEN .
It represents the ratio of Hydronium ions (H3O) to Hydroxide ions (OH). It is a measure of acidity and alkalinity of a solution.
FOLLOW MEExplain how the energy of a toy car is transformed as it slides down a ramp. Give evidence that the energy of the car remains the same at all points on the ramp. (30 points)
Answer:
As the car starts to slide down the ramp, it is kinetic energy and when it's on the top of the ramp, it is potential energy. We can see that the energy is now being transferred through the car and ramp.
Am I correct?
(Plz don’t used this for points or typing random things…plz don’t)
Answer and Explanation:
The answers would be:
A. Domestic cats live in about 34% of homes in the United States. (Statistical statements are, most of the time, facts and not an opinion)
C. Modern domestic cats are closely related to Near Eastern wildcats. (Fact)
D. Cats eat rodents that can spread disease. (Fact)
The above statements are facts because they don't make a judgement or show a position on the topic, only show what is known and proven to be true.
B and E are incorrect because they take a side of the topic, in which someone else might disagree with the opinion. These opinions aren't proven to be true.
#teamtrees #PAW (Plant And Water)
I hope this helps!
Which of the following is the correct chemical formula for Ca and F? CaF Ca2F CaF2
Answer:
CaF2
Explanation:
Calcium fluoride is a solid formed by the chemical combination of Calcium (Ca) and Fluorine (F). Two molecules of fluorine (F2) and one molecule of Calcium (Ca) are needed to form the Calcium Fluoride molecule.
An ionic bond is formed between the Calcium and Fluorine atoms i.e. electrons are transferred from calcium atoms to fluorine atoms. The calcium ion is a cation with formula; Ca2+ while fluorine is an anion with formula; F-. Hence, it takes two molecules of Fluorine ion (F-) to form a relatively stable and neutral molecule with 1 molecule of Calcium ion (Ca2+).
The specific heat capacity of a pure substance can be found by dividing the heat needed to change the temperature of a sample of the substance by the mass of the sample and by the change in temperature. The specific heat capacity of a certain substance has been measured to be 3.52 J/g °C. Suppose 420.0 g of the substance is heated until the temperature of the sample has changed by 43.8 °C.
Write an equation that will let you calculate the last Q that was needed for this temperature change. Your equation should contain only symbols. Be sure to define each symbol.
Answer:
The answers to your questions are given below.
Explanation:
Data obtained from the question include:
Mass (M) = 420.0 g
Temperature change (ΔT) = 43.8 °C
Specific heat capacity (C) = 3.52 J/g °C
Heat needed (Q) =...?
The heat needed for the temperature change can be obtained by using the following formula:
Q = MCΔT
Where:
Q is the heat needed measured in joule (J).
M is the mass of substance measured in grams (g)
C is the specific heat capacity of the substance with unit J/g °C.
ΔT is the temperature change measured in degree celsius (°C).
Thus, we can calculate the heat needed to change the temperature as follow:
Q = MCΔT
Q = 420 x 3.52 x 43.8
Q = 64753.92 J
Therefore, the heat needed to cause the temperature change is 64753.92 J
Which soil would most likely be found in the Arctic?
Answer:
The answer is B
Explanation:
Gelisols
One day, you decide to pop some popcorn. You put the bag in the microwave, but after a couple of minutes of cooking it is clear the popcorn is not popping. Why did this happen? What steps could you take to help locate the problem?
I'm a hot 15yo boy hml
Answer:
great
On a scale of 1-10 I give you a 10
Explanation:
what about brainliest
Answer: I agree 100%
Explanation: But you may be too hot for me lol.
In science class, Jake mixed water with differing amounts of an unknown liquid. After mixing the liquids, he heated 20 milliliters (ml) of each mixture and observed how quickly it boiled. The table shows his results.
According to the question, each mixture decrease the boiling point of the water.
What is boiling point ?Boiling temperature is defined as the temperature at which liquid change into a vapour at the atmospheric pressure at sea or ocean level.
For example the boiling temperature of water is 100 degree celcius.
Thus, each mixture decrease the boiling point of the water, option "A" is correct.
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are these following a basic radical or acid radical?
1. Chlorate
2. Peroxide
3. Silver
4. Zinc
5. Nitrite
Answer:
chlorate=Acid
peroxide=Acid
silver=Acid
zinc= Basic
nitrite=Acid
Please be I need this quick
2. For each pair of atoms determine which can steal an electron easier (higher electronegativity),
draw a picture of Bohr's model, and explain why:
a. Oxygen and Fluorine
b. Sodium and Potassium
c. Boron and Calcium
Answer: Option (A) is the correct answer.
Explanation:
An atom who has seven valence electrons in its ground state will have the following electronic configuration in its sub shells as 2, 7.
Thus, there will be in total 9 electrons and it is known that fluorine has atomic number 9.
Whereas sodium has 2, 8, 1 electrons in its sub-shell.
Calcium has 2, 8, 8, 2 electrons in its sub-shell and oxygen has 2, 6 electrons in its sub-shell.
Thus, we can conclude that out of the given options, fluorine is the element whose atom in the ground state has seven valence electrons.
PLEASE PLEASE HELP!! A pipe drips at 155mL/day- convert this rate to gallons/day (1gal=3.785L)
1 mL =[tex]10^{-3}[/tex] L
so $155$ mL =$155\times10^{-3}$ L
Now, $1$ gallon = $3.785$ L , or $1$ L= $\frac1{3.785}$ gallons
so $155\times10^{-3}$ L= $155\times10^{-3}\times \frac{1}{3.785}=40.95\times 10^{-3}$ gallons
and this is for each day, so just divide by 1 (day) to get the ratw gallons/day
i.e. $40.95\times 10^{-3}$ gal/day
can someone tell me what does the numbers in the circle mean? and how do I find it?
Answer:
Electronic configurations of three magnesium atoms and two nitrogen atoms.
[tex]{ \sf{.}}[/tex]
If you started with 2 moles of Nitrogen and 3 moles of Hydrogen, then you
would not have any leftover reactants. Explain which material would be
limiting since no hydrogen or nitrogen were left over?
N2 + 3H2 -> 2NH3
Answer: 0.3 moles NH3
Explanation:
10. Calculate the percent, by weight, of carbon in 154 g of Ca4H803 (A) 46% (B) 31% (C) 72% (D) 27% (E) 55%
Answer:
The answers are below
Explanation:
A) 46% of 154 = 70.84
B) 31% of 154 = 47.74
C) 72% of 154 = 110.88
D) 27% of 154 = 41.58
E) 55% of 154 = 84.7
Which of the following is an example of the geosphere interacting with the atmosphere?Streams become muddy due to erosion.
Volcanic eruptions release gases into the air.
Rocks crack open when water in the cracks freeze.
Plants absorb carbon dioxide and produce oxygen.
Answer:
Volcanic eruptions release gases into the air.
Explanation:
This is because the atmosphere collects the gas from the volcano, the volcano is apart of the geosphere because it is a part of the earth's surfaces.
Help pls!! Will having to do course recovery to make up a pass grade affect your college application In a bad way and how colleges see you?
Josefina and Raul were comparing how sound moves through various mediums and how charge moves through conducting wires. They performed experiments to find out if the factors that determine the speed of sound are the same as those that determine the flow in a circuit. What did they find? Describe two things that they found. For each, explain how the speed of sound and flow of current are affected
They found that difference occurs in the speed of both sound and charges occur due to the difference in the type of medium.
Sound and charges needs specific medium for faster movement i.e. sound moves faster in solid as compared to liquid and gas whereas charges moves faster and easily in gold due to lower resistance which is followed by copper. Sound can move from solid, liquid and gases whereas charges move only in solid metal in which free electrons are present. The speed of sound and flow of current are affected due to difference in the arrangement of atoms in solid, liquid and gas.
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Luisa is flying from Dallas to New York to visit her cousin. Her carry-on bag weighs 39.4 lbs. However, there is a weight restriction of 18 kg per bag. Will she be permitted to bring her bag on the plane?