Answer:
A) The reaction is an exothermic reaction
B) 12.744 kJ
c) 49.976 KJ/mol . NaOH
Explanation:
A) The reaction is an exothermic reaction
B) calculate the amount of heat that was released or absorbed by the reaction in this case. kJ
Assuming : specific heat of solution = specific heat of water = 4.186 J/g°C
mass of solution = 10.2 + 250 = 260.2 g
determine The heat released in the reaction
= mass of solution * specific heat of solution * temperature change
= 260.2 * 4.186 * ( 32.7 - 21 )
= 12.744 kJ
C) Calculate the reaction enthalpy ΔH per mole of NaOH. mol
Reaction enthalpy = - heat released / ( 10.2 /40 )
= - 12.744 / ( 10.2/40 ) = - 49.976 KJ/mol . NaOH
A student dissolves 12.1 g of potassium chloride (KCl) in 250. g of water in a well-insulated open cup. He then observes the temperature of the water fall from 21.0 °C to 17.1 °C over the course of 6.9 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
KCl(s) → K (aq) + Cl (aq)
a. Is this reaction exothermic, endothermic, or neither?
b. Calculate the reaction enthalpy ΔH.rxn per mole of KCI.
Answer:
a. Endothermic
b. 26.37kJ/mol
Explanation:
a. As we can see, the temperature of the water is decreasing when the reaction is occurring, that means the reaction is absorbing heat and is endothermic
b. To find the enthalpy we must find the change in heat when 12.1g of KCl are dissolved. Using the equation:
Q = -m*ΔT*C
Where Q is change in heat
m the mass of solution (250g + 12.1g = 262.1g)
ΔT is change in heat (17.1°C - 21.0°C = -3.9°C)
And C is specific heat of the solution (4.184J/g°C assuming is the same than the specific heat of water).
Replacing:
Q = -262.1g*-3.9°C*4.184J/g°C
Q = 4277J = 4.28kJ
As reaction enthalpy is the change in heat per mole of reaction, we must find the moles of 12.1g of KCl:
Moles KCl -Molar mass: 74.55g/mol-:
12.1g KCl * (1 mol / 74.55g) = 0.1623 moles KCl
The reaction enthalpy us:
4.28kJ / 0.1623mol = }
26.37kJ/mol
450. grams of water are heated from 20.0 °C to 37.0 °C. How many kcal were absorbed by the water? Note that this is the amount of heat absorbed when a glass of cold water is consumed.
Answer:
Q = 32,007.6 J
Explanation:
Hello there!
In this case, since the energy involved during a heating/cooling process is:
[tex]Q=mC(T_f-T_i)[/tex]
Thus, given the mass, specific heat of water, initial temperature and final one, we plug in obtain:
[tex]Q=450g*4.184\frac{J}{g\°C} (37.0\°C-20.0\°C)\\\\Q=32,007.6J[/tex]
Best regards!
Which of the following sentences uses commas correctly?
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I got all of the answers on the test correct, didn't I?
I, got all of the answers on the test correct didn't I?
I got all of the answers, on the test correct didn't I?
I got all of the answers on the test, correct didn't I?
what structure and bonds are formed in group 1 elements
what should i do the next time i see someone that i havent seen in a year and they said they want to kiss me
Answer:
Well if you want to kiss them go for it, but if you don't then say sorry but I don't feel comfortable with that.
Hope everything goes well <3
Carbon monoxide is a colorless, odorless gas that binds irreversibly to hemoglobin in our blood, causing suffocation and death. CO is formed during incomplete combustion of carbon. One way to represent this equilibrium is: CO(g)C(s) 1/2 O2(g) We could also write this reaction three other ways, listed below. The equilibrium constants for all of the reactions are related. Write the equilibrium constant for each new reaction in terms of K, the equilibrium constant for the reaction above.
The question is missing some parts. Here is the complete question.
Carbon monoxide is a colorless, odorless gas that binds irreversibly to hemoglobin in our blood, causing suffocation and death. CO is formed during incomplete combustion of carbon. One way to represent this equilibrium is:
[tex]2CO_{(g)}[/tex] ⇄ [tex]2C_{(s)}+O_{2}_{(g)}[/tex]
we could also write this reaction three other ways listed below. The equilibrium constant for all of the reactions are related. Write the equilibrium constant for each new reaction in terms of K, the equilibrium constant for the reaction above.
1) [tex]2C_{(s)}+O_{2}_{(g)}[/tex] ⇄ [tex]2CO_{(g)}[/tex] K₁ =
2) [tex]C_{(s)}+1/2O_{2}_{(g)}[/tex] ⇄ [tex]CO_{(g)}[/tex] K₂ =
3) [tex]CO_{(g)}[/tex] ⇄ [tex]C_{(s)}+1/2O_{2}_{(g)}[/tex] K₃ =
Answer: 1) [tex]K_{1}=\frac{1}{K}[/tex]
2) [tex]K_{2}=\frac{1}{K^{1/2}}[/tex]
3) [tex]K_{3}=K^{1/2}[/tex]
Explanation: A chemical reaction can be reversible, i.e., can proceed in both directions: to the right of the arrow (forward) or towards the left of the arrow (backward).
When the rates of forward and backward reactions are the same, the reaction is in equilibrium. In that state, we can determine the equilibrium constant, [tex]K_{c}[/tex].
For the first way to represent equilibrium of CO formed, the [tex]K_{c}[/tex] is calculated
[tex]2CO_{(g)}[/tex] ⇄ [tex]2C_{(s)}+O_{2}_{(g)}[/tex]
[tex]K=\frac{[O_{2}]}{[CO]^{2}}[/tex]
in which the symbol [ ] is concentration of the compound.
In equilibrium constant, solids are not included.
Equilibrium constants for the other reactions:
1) [tex]2C_{(s)}+O_{2}_{(g)}[/tex] ⇄ [tex]2CO_{(g)}[/tex]
[tex]K_{1}=\frac{[CO]^{2}}{[O_{2}]}[/tex]
Comparing K₁ and K, the first one is the inverse of K, so writing in terms of K
[tex]K_{1}=\frac{1}{K}[/tex]
2) [tex]C_{(s)}+1/2O_{2}_{(g)}[/tex] ⇄ [tex]CO_{(g)}[/tex]
[tex]K_{2}=\frac{[CO]}{[O_{2}]^{1/2}}[/tex]
In terms of K, K₂ is
[tex]K_{2}=\frac{1}{K^{1/2}}[/tex]
3) [tex]CO_{(g)}[/tex] ⇄ [tex]C_{(s)}+1/2O_{2}_{(g)}[/tex]
[tex]K_{3}=\frac{[O_{2}]^{1/2}}{[CO]}[/tex]
This constant in terms of K will be
[tex]K_{3}=K^{1/2}[/tex]
In conclusion, K₁, K₂ and K₃ in terms of K is [tex]\frac{1}{K}[/tex],[tex]\frac{1}{K^{1/2}}[/tex] and [tex]K^{1/2}[/tex], respectively.
When running an experiment, it is essential to record data and observations within your lab notebook. The data and observations are then discussed and analyzed, results and discussion. However, as you write a conclusion, some data are more important to include than others. Which of the following data would you include if you had to write a conclusion in for outcome of this week's LLE experiment?
a. MP range of product
b. mass of product
c. mass of flask and cork support
d. instrument used to evaporate the solvent
e. volume of crude reaction mixture used
f. % recovery
g. volume of acid and base used
h. theoretical MP
i. mass of flask, cork support, and product
Answer:
% recovery
MP range of product
mass of product
Explanation:
Liquid–liquid extraction (LLE) is a process of transferring one (or more) solute(s) which are present in a feed solution to another immiscible liquid (solvent). The other solvent that becomes enriched in the target solute(s) is called extract. The original feed solution that is depleted in solute(s) is subsequently referred to as the raffinate.
This method is used to purify compounds and separate mixtures of compounds. This is very important when we want to isolate a product from a reaction mixture.
The percent recovery is the amount of solute that is transferred to the extract. This is the most important data to be recorded in an LLE experiment.
The melting point range necessarily helps us to identify the product and the mass of solid tells us the quantity of the solid obtained after extraction.
Read the choices below. then select ALL choices that are true.
Higher temperature will cause more collisions.
Lower temperature will cause less collisions.
Higher temperature provides more activation energy!
Lower temperatures cause some atoms to bounce off each other and not react.
Answer:
Higher temperature will cause more collisions.
Lower temperature will cause less collisions.
Higher temperature provides more activation energy!
Explanation:
pls mark brainliest :)
Before spectroscopy was invented, Korner's absolute method had been used to determine whether a disubstituted benzene derivative was the ortho, meta, or para isomer. Korner's method involves adding a third group (often a nitro group) and determining how many isomers are formed. A turn-of-the-20th-century chemist isolated an aromatic compound of molecular formula C6H4Br2. He carefully nitrated this compound and purified three isomers of formula C6H3Br2NO2, one of which was obtained in very small amounts. Propose a structure for the original compound.
Answer:
Answer is explained in the explanation section below.
Explanation:
Definitely, before the invention of spectroscopy, Korner's absolute method had been in use. So, the proposed structure is a diagram, that we can not draw here. Therefore, I have drawn it separately and attached in the attachment below. Please for this answer, refer to the diagram which is a proposed structure attached in the attachment below.
Proposed Structure is:
1,3-Dibromo Benzene.
In the Korner's method, 1,3- Dibromo benzene undergoes nitration process in the presence of HNO3/H2SO4.
The original compound that undergoes nitration is a meta disubstituted aromatic compound.
After nitration, 1,3-Dibromo benzene yields three having chemical formula C6H3Br2NO2.
The surface particles of a sample of matter experiences a strong downward pull
and stretch tight enough for a spider to walk on. This is an example of?
HELP PLEASE ITS DUE TODAY, THANK U!
When do Florida plants prepare themselves for the cold winter temperatures? (1 point)
a
Beginning of the spring
b
During the fall
c
End of the spring
d
End of the summer
PLEASE HELP ASAP!!! >.
Answer:
A. Beginning of the spring
Explanation:
Pa like, Pa follow, Pa rate
The Gulf Stream flows along the equator before turning north along Florida’s east coast. How does the Gulf Stream impact Florida’s climate?
Answer:
The Gulf Stream is influential on the climate of the Florida peninsula.East winds moving over this warm water move warm air from over the Gulf Stream inland, helping to keep temperatures milder across the state than elsewhere across the Southeastern United States during the winter.
Explanation:
hope this helps!
Answer:
The Gulf Stream is influential on the climate of the Florida peninsula.East winds moving over this warm water move warm air from over the Gulf Stream inland, helping to keep temperatures milder across the state than elsewhere across the Southeastern United States during the winter.
Explanation:
Hope This Helps!
For each of the following compounds, decide whether the compound's solubility in aqueous solution changes with pH.
a. Ca(OH)2
b. CuBr
c. Ca3(PO4)2
Answer:
a. pH raises
b. pH neutral
c. pH raises
Explanation:
First of all we need to dissociate these compounds.
Ca(OH)₂ → Ca²⁺ + 2OH⁻
This is the calcium hydroxide, a strong base.
In this case, we are giving OH⁻ to medium, so the pH will be increased.
OH⁻ + H⁺ ⇄ H₂O
Hydroxides will neutralize the protons in order to make water, but if we have many OH, we talk about a basic solution where pH is lower than 7.
b. CuBr → Cu⁺ + Br⁻
This is similar to NaCl, a ionic salt which is neutral.
The ions from this salt, do not make hydrolisis, that's why pH does not change.
c. Ca₃(PO₄)₂ → 3Ca²⁺ + 2PO₄⁻³
Calcium cathion comes from a strong base. It means, that the ion can not make hydrolisis because it is the conjugate weak acid.
Phosphate anion comes from a weak acid, it can gives OH⁻ to medium so pH will increase; the PO₄⁻³ anion is the conjugate strong base of the phosphoric acid, that's why it can react:
PO₄⁻³ + H₂O ⇄ H₂PO⁻² + OH⁻
A metal ion (X) with a charge of 4+ is attracted to non metal ion (Z) with a charge of 3-. Which of these formulas represents the resulting compound pls answer asap options in photo
Answer:
D
Explanation:
the charges need to balence out
so finding the LCM which is 12 we find we need 3x's
and 4 zs
so that makes the formula X3Z4 which is D
g Which of the following solutes in aqueous solution would be expected to exhibit the smallest freezing-point lowering (assuming ideal behavior)? In other words, which one would have the highest freezing point temperature? A) 0.20 m CaCl2 B) 0.50 m C2H5OH (ethanol) C) 0.10 m Al(NO3)3 D) 0.25 m NH4Br E) 0.30 m NaCl
Answer:
0.10 m Al(NO3)3
Explanation:
Let us note that the substance that has the highest freezing point will have the lowest freezing point depression. Since;
ΔTf = Kf m i
ΔTf = freezing point depression
Kf = freezing point constant
m = molality
i = Van't Hoft factor
Given that the freezing point depression depends on the molality and the Van't Hoft factor (number of particles), we can see that 0.10 m Al(NO3)3 has the least freezing point depression and highest freezing point temperature because it gives the least value of m * i. That is 0.10 m * 4 = 0.4
Is a burning log an exothermic or endothermic event if the log is the (system) ?
Answer:
Exothermic Reaction
Explanation:
Burning wood in air is an exothermic process (it releases heat), but there is an energy barrier, so it requires a bit of heat in the beginning to get the reactions started.
Wood reacts with oxygen in the air to form (mostly) carbon dioxide and water vapor. The process involves many different individual chemical reactions, and it requires some energy to initiate the reactions. This is because it's usually necessary to break some chemical bonds (endothermic) before new stronger bonds can be formed (exothermic). Overall, though, more heat is released in forming the final products than is consumed in starting new reactions.
Have a great day <3
In the given question, a burning log is an exothermic event if the log is the system.
An exothermic reaction releases energy to the surroundings, usually in the form of heat. The change in enthalpy is negative.
When a log burns, it reacts with oxygen in the air to produce carbon dioxide, water vapor, and heat. This heat is released to the surroundings, making the burning log an exothermic event.
Therefore, a burning log is an exothermic event if the log is the system. This is due to the fact that the reaction emits heat into the environment, making it an exothermic reaction.
Learn more about exothermic reaction here:
https://brainly.com/question/28546817
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What is one of the major conclusions made from the study of line spectra of various elements?
A)
the movement of electrons outside the nucleus
B)
absorption and emission of energy is quantized
C)
the presence of energy beyond the visible spectrum
D)
the presence of electrons outside the nucleus of an atom
Answer:
B
Explanation:
what is the name of these 4 compound in isomers
Answer:
C9H19 C5H12 C6H17 C7H20
which type of rock is rhyolite A.Intusive igneous B.Sedimentary C.Extrusive igneous D.Metamorphic
Answer:
C - Extrusive igneous
Explanation:
Rhyolite is an extrusive igneous due to the high silica content, the lava is very dangerous.
Answer:
Its C
Explanation:
A P E X
anyone wanna do my chem test for 500 points? my insta is niqsariot_1 hmu if your interested and for everyone else FREE 100 POINTS
Answer:
I would be if I do it your no learning anything but I would but I don't have insta yet
Explanation:
sorry
Answer:
k
Explanation:
The lobes are important for speech and language. O A. parietal O B. temporal o o Ο Ο C. frontal O D. occipital
Answer:
Explanation:
D or b
Sorry if wrong
Answer:
temporal
Explanation:
How many moles in 6.57 x 10^24 formula units of NaCl?
0.092 moles
10.91 moles
3.96 X 10^49 moles
145 moles
Answer:
3.955*10^48
Explanation:
1 mole of a substance gives 6.02*10^23/6.57*10^24 will give x then cross multiply the answer. is 3.955*10^48
Help pls! I need help im just writing to use the character limit!
Answer:
se que la imaje es un poco confusa con la materia pero
desiaria ayudarte pero CREO que con mi TÉCNICA es la A
Which ecosystem is most resilient to change due to its high diversity?
mountain meadow
stormwater pond
coral reef
arctic fundra
Answer:
coral reef
Explanation:
Liquid hydrogen boils at -252°C. What is the boiling point on the Kelvin scale?
Answer:
Boiling point in kelvin is 373.1 \
boiling point of liquid hydrogen in kelvin is 21.15
Explanation:
What is the formula for Decaoxygen pentasulfide
Answer:
Compound Formula. 1, Carbon dioxide, CO2. 2, Carbon monoxide, CO. 3, Diphosphorus pentoxide, P2O5. 4, Dinitrogen monoxide, N2O.
Explanation:
dont even know by thoAnswer:
Explanation:
Why does Hydrogen not belong to any group?
Answer: Hydrogen is not in any group because it only has on electron
Explanation:
g antimony is used as a catalyst in the production of many plastic polyesters. if the plasticis used as a container, some trace amounts of antimony may diffuse into the interior. whileexperimenting, you determine that 44.7μg/lof antimony is present in a batch of fruit juice.at that rate, how many moles of antimony would you expect to find in a gallon of the juice?note that the molecular mass of antimony is 121.76g/mol
Answer:
1.39x10⁻⁶ mol
Explanation:
First we convert the gallon of juice to liters:
1 gallon = 3.785 LThen we calculate the mass of antimony that would be in 3.785 L, using the given concentration:
44.7 μg/L * 3.785 L = 169.2 μgThen we convert mass into moles, using the molecular mass:
169.2 μg ÷ 121.76 μg/μmol = 1.39 μmolFinally we convert μmol into mol:
1.39 μmol = 1.39x10⁻⁶ molIf two-parent with AB blood group claim and say that they have a baby with O blood group is born to them and it is their own baby and not adopted. Do you think they are speaking the truth?
who knows this answer
In this stage of team building, the team is running smoothly and they are comfortable in their roles.
norming
performing
forming
storming
Answer:
performing
Explanation: