Solution :
Given :
Initial temperature of the refrigerant is :
[tex]$T_i=39.37 ^ \circ C$[/tex]
= ( 39.37 + 273 ) K
= 312.3 K
Room which is maintained at constant temperature is :
[tex]$T_o=22 ^ \circ C$[/tex]
= (22+273) K
= 295 K
The thermal energy transferred to the room is :
Q = 400 kJ
= [tex]$400 \times 10^3 \ J$[/tex]
Therefore, the total entropy generation during the thermal energy process is :
[tex]$\Delta S =\left[\frac{-Q}{T_i}+ \frac{+Q}{T_i}\right]$[/tex]
Here, -Q = heat is leaving the system maintained at a temperature of [tex]$T_i$[/tex] K.
+Q = heat is entering the system maintained at a temperature of [tex]$T_o$[/tex] K.
Therefore, substituting the values :
[tex]$\Delta S =\left[\frac{-400\times 10^3}{312.3}+ \frac{400\times 10^3}{295}\right]$[/tex]
= [-1280.8197 + 1355.9322]
= 75.1125 J/K
= 0.0751125 kJ/K
= 0.075 kJ/K
Questions
Determine the primary and secondary valencies of the following complexes and calculate their spin only magnetic
moment.
iii. [Cu(OH2)6]504
i. K[TI(CN).]
ii. [V(NH3)4Br2]
iv. K3 [Cr(CN)6]
Answer:
yes
Explanation:
yes
Astronauts must be protected from extreme heat while
reentering the Earth's atmosphere. Scientists can use the
engineering design process to help make reentry safer.
You have defined the problem as a need for heat shields to be stronger. What
should be your next step in using the engineering design process to solve the
problem?
O A. Communicate your solution to your team members.
O B. Update your initial design for the heat shield.
O C. Identify the criteria and constraints of the project.
O D. Build a prototype of a possible new type of heat shield.
The next engineering step to be taken is to update your initial design for the heat shield.
What is a heat sheild?The term heat sheild refers to a device that can be used to shield an from astronaut extreme heat especially as they re-enter the earth's atmosphere.
After you have identified the problem, the next engineering step to be taken is to update your initial design for the heat shield.
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Once the concentration of the common ion is increased______.
a. the solubility of the ionic solid increases.
b. the solubility of the ionic solid decreases.
c. the solubility of the common ion increases.
d. the solubility of the common ion decreases.
Answer:
B
Explanation:
When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II) sulfate PbSO4 is reduced to lead at the cathode and oxidized to solid lead(II) oxide PbO at the anode.Suppose a current of 62.0 is fed into a car battery for 23.0 seconds. Calculate the mass of lead deposited on the cathode of the battery. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.
Answer: The mass of lead deposited on the cathode of the battery is 1.523 g.
Explanation:
Given: Current = 62.0 A
Time = 23.0 sec
Formula used to calculate charge is as follows.
[tex]Q = I \times t[/tex]
where,
Q = charge
I = current
t = time
Substitute the values into above formula as follows.
[tex]Q = I \times t\\= 62.0 A \times 23.0 sec\\= 1426 C[/tex]
It is known that 1 mole of a substance tends to deposit a charge of 96500 C. Therefore, number of moles obtained by 1426 C of charge is as follows.
[tex]Moles = \frac{1426 C}{96500 C/mol}\\= 0.0147 mol[/tex]
The oxidation state of Pb in [tex]PbSO_{4}[/tex] is 2. So, moles deposited by Pb is as follows.
[tex]Moles of Pb = \frac{0.0147}{2}\\= 0.00735 mol[/tex]
It is known that molar mass of lead (Pb) is 207.2 g/mol. Now, mass of lead is calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\ 0.00735 = \frac{mass}{207.2 g/mol}\\mass = 1.523 g[/tex]
Thus, we can conclude that the mass of lead deposited on the cathode of the battery is 1.523 g.
Is anyone good at chemistry if so can someone please help me NO LINKS PLEASE
Answer:
I think it's (a) all of the materials will reach the same temperature and heat flow will stop.
What happens when an electron moves to a higher energy level?
A. It releases energy of a specific frequency
B. It gains energy in a quantized amount.
C. It loses energy in the form of light.
D. It absorbs photons of many energies
ANSWER: B. It gains energy in a quantized amount.
Answer:
B. It gains energy in a quantized amount.
what are the products of this reaction
Cu+AgNO3
Answer:
1 Cu + AgNO3 → Ag + CuNO3
2 Cu + Ag(NO3)2 → Ag + CuNO3
Explanation:
plzzz mark me brainliest
g For the reaction Ag2S(s)⇌2Ag+(aq)+S2−(aq)Ag2S(s)⇌2Ag+(aq)+S2−(aq), Keq=2.4×10−4Keq=2.4×10−4, and the equilibrium concentration of sulfide ion is [S2−]=0.0023M[S2−]=0.0023M. What is [Ag+]atequilibrium?
Answer:
0.32 M
Explanation:
Step 1: Write the balanced reaction at equilibrium
Ag₂S(s) ⇌ 2 Ag⁺(aq) + S²⁻(aq)
Step 2: Calculate the concentration of Ag⁺ at equilibrium
We will use the formula for the concentration equilibrium constant (Keq), which is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. It only includes gases and aqueous species.
Keq = [Ag⁺]² × [S²⁻]
[Ag⁺] = √{Keq / [S²⁻]}
[Ag⁺] = √{2.4 × 10⁻⁴ / 0.0023} = 0.32 M
Pls help me with this
Answer:
[tex][I_2]=[Br]=0.31M[/tex]
Explanation:
Hello there!
In this case, according to the given information, it is possible for us to set up the following chemical equation at equilibrium:
[tex]I_2+Br_2\rightleftharpoons 2IBr[/tex]
Now, we can set up the equilibrium expression in terms of x (reaction extent) whereas the initial concentration of both iodine and bromine is 0.5mol/0.250L=2.0M:
[tex]K=\frac{[IBr]^2}{[I_2][Br_2]} \\\\1.2x10^2=\frac{(2x)^2}{(2.0-x)^2}[/tex]
Thus, we solve for x as show below:
[tex]\sqrt{1.2x10^2} =\sqrt{\frac{(2x)^2}{(2.0-x)^2}} \\\\10.95=\frac{2x}{2.0-x}\\\\21.91-10.95x=2x\\\\21.91=12.95x\\\\x=\frac{21.91}{12.95} \\\\x=1.69M[/tex]
Therefore, the concentrations of both bromine and iodine are:
[tex][I_2]=[Br]=2.0M-1.69M=0.31M[/tex]
Regards!
What is the the heat of reaction, delta, in kJ/mol?
a) -26kJ/mol
b) -25kJ/mol
c) -10kJ/mol
d)-35kJ/mol
Answer:
b) -25 kJ/mol.
Explanation:
Hello there!
In this case, since the general definition of the enthalpy of reaction involves the subtraction of the energy of the products and the energy of the reactants:
[tex]\Delta H=H_{prod}-H_{react}[/tex]
Thus, since the graph shows that the energy of the products is 20 kJ/mol and that of reactants 45 kJ/mol, we will obtain:
[tex]\Delta H=20kJ/mol-45kJ/mol\\\\\Delta H=-25kJ/mol[/tex]
Which means it is exothermic.
Regards!
Pls help I will give brainliest
Answer:
paki sagot naman pls para my isagot ako sa module ko ty
what volume of h2 can be produced at stp from 2 mol cah2 and excess water if the reaction goes 100% to completion?
Answer:
89.6 L of H₂ will be produced at STP from 2 moles of CaH₂ and excess water if the reaction goes to 100% completion.
Explanation:
The balanced chemical equation of the reaction between calcium hydride, CaH₂ and excess water to produce calcium hydroxide and hydrogen gas is given below:
CaH₂ (s) + 2H₂O (l) ----> Ca(OH)₂ (aq) + 2H₂ (g)
From the equation of the chemical reaction above, 1 mole of calcium hydride reacts with 2 moles of water to produce 2 moles of hydrogen gas.
Then, 2 moles calcium hydride will react with excess water to produce 2 × 2 -moles of hydrogen gas = 4 moles of hydrogen gas.
One mas a gas at STP has a volume of 22.4 L
4 moles of hydrogen gas will have a volume of 4 × 22.4 L = 89.6 L
Therefore, 89.6 L of H₂ will be produced at STP from 2 moles of CaH₂ and excess water if the reaction goes to 100% completion.
what is the
structure and symmetry operation of naphthalene
Answer:
Naphthalene has C2-rotational axis passing through the C9-C10 bond. It has two C2-axes perpendicular to the principal C2-rotational axis (one is passing through the mid-point of the C9-C10 bond another passing through the midpoints of C2-C3, C9-C10, C6-C7 bonds).
Explanation:
What happens in radioactive decay?
O A. An electron is lost to form a negatively charged particle.
O B. An unstable nucleus breaks down into smaller parts.
O C. Two smaller nuclei are joined to form one larger nucleus.
O D. A large nucleus breaks apart to form smaller nuclei.
SHIRME
A radioactive atom will spontaneously release radiation in the shape of energy rather than particles in order to transition into a more steady state.
Why is something radioactive?Radioactivity, as its name suggests, seems to be the act of generating radiation without any external cause. This is carried out by an unstable atomic nucleus that "wants" to abandon certain power in order to change to a more stable form.
Are people radioactive at all?Absolutely, since humans consume radioactive materials from the environment through food, drink, and air, our bodies are inherently radioactive. Our bodies take these substances in and store them in our bones, tissues, and organs. We also breathe them in and consume them.
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A student has a sample of 1.42 moles of fluorine gas that is contained in a 28.1 L container at 305 K. What is the pressure of the sample?
Answer:
P = 1.26 atm
Explanation:
Given that,
The number of moles, n = 1.42 mol
Volume, V = 28.1 L
Temperature, T = 305 K
We need to find the pressure of the gas. The ideal gas law is as follows :
[tex]PV=nRT\\\\P=\dfrac{nRT}{V}[/tex]
R = 0.0821 L-atm/mol-K
Put all the values,
[tex]P=\dfrac{1.42 \times 0.0821\times 305 }{28.1 }\\\\P=1.26\ atm[/tex]
So, the pressure of the gas is 1.26 atm.
1. The density of gasoline is 0.7 g/ml. What is the mass of 400L of gasoline?
Answer:
280,000g
Explanation:
0.7g/mL x 1000mL/1L x 400L = 280,000g
what is solubility? .
Ionic bonds result from elements ____.
A. that share electrons
B. with high electronegativity differences
C. That form polar bonds
D. That are only nonmetals
HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Which of the following statements is true?
Some plants cannot reproduce.
Pollen contains male sperm cells.
Mitosis results in two non-identical cells.
Flowering plants reproduce using spores.
Answer:
errccvbnnbb
Explanation:
jjuxxxsyy
Answer:
i think it the third one
Explanation:
sorry if im wrong are u in biology?
describes the oil-free paint manufacturing process
Answer:
which account for over 60% of total resin use in the USA. The main pigment was titanium dioxide and the major solvents aliphatic hydrocarbons
Explanation:
12 points
Methyl methacrylate has a molar mass of 100 g/mole When a sample of methyl methacrylate weighing 3.14 g was completely combusted, the only products formed
were 6.91 g of CO2 and 2.26 g of water. What is methyl methacrylate's molecular formula?
O A C5H8O2
OBC6H120
OCC7H16
OD. None of the above
O E C4H403
Answer:
C₅H₈O₂
Explanation:
methyl methacrylate = 100 amu
6.91g CO₂ = 0.157 moles
2.26g H₂O = 0.125 moles
0.157 ÷ 0.125 = 1.256
{(CO₂)₁.₂₅₆ + (H₂O)₁} × 4 = (CO₂)₅ + (H₂O)₄
C₅H₈O?
C₅ = 60.05 amu H₈ = 8.064 amu
60.05 + 8.064 = 68.114 amu
100 amu - 68.114 amu = 31.886 amu
O = 16 amu
O = 2
The molecular formula of methyl methacrylate is C₅H₈O₂. The correct option is A, C₅H₈O₂.
What is methyl methacrylate?
Methyl methacrylate (MMA) is a colorless liquid monomer with a distinctive fruity odor. It is an organic compound that belongs to the family of acrylic esters.
We have to determine the empirical formula of methyl methacrylate first and then multiply it by the integer n to determine the molecular formula. Empirical formula:
CO₂ and H₂O are the combustion products of methyl methacrylate.
C₅H₈O₂ + (9n / 2)
O₂ → 5CO₂ + (n)H₂O
There are 5 C atoms and (8 + 2n), H atoms in the left and 5 C atoms, and n H atoms in the right.
5C = 5C, and 8 + 2n = nH.
n = 6
Molecular formula calculation is dividing the molecular weight by the empirical formula weight to determine the multiplication factor.
C₅HₙO₂ (empirical formula) has a weight of:
(5 x 12.011) + (8 x 1.008) + (2 x 15.999) = 100.12 g/mol
The actual molecular weight of methyl methacrylate is 100 g/mol.
Therefore, the molecular formula is (C₅H₈O₂) x 1, which is C₅H₈O₂, option A.
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A 2.5 M solution of a weak acid is prepared. Using a pH meter, the pH is measured to be 5.1. Calculate the acid ionization constant, [tex]K_{a}[/tex] , of this weak acid.
Show your work
Molarity of acid=2.5M
pH=5.1.
ka=?
Now
We need to write an eqn to show the dissociation of the acid
HA + H2O === H3O+ + A-
Writing The Equilibrium(Or Acid dissociation constant) of this reaction
Ka =[H3O+] {A-]/ {HA].
The concept behind this is
concentration of Products divided by those of reactants. Water is not written because its a pure liquid and does not affect the Equilibrium constant.
Now If you have any Idea on ICE tables..
You'd know that the concentration of acid will decrease by 2.5-x
Whilst the products...will increase by x each
Note: This is when the ratio of their Moles are in 1:1
ka= x.x/2.5-x
Since the Moles of A- and H3O+ are in 1:1... Their concentrations at equilibrium will be the same
so
Ka= x²/2.5-x
Now what is x??
x is the Hydrozonium ion concentration.
we can get it from the pH formula
pH= -log (H3O+)
Making H3O+ subject by applying Logarithm Rules
H3O+ = 10^-ph
x=10^-5.1
=7.94x10^-6.
Now back to Ka
Ka= x²/2.5-x
Ka= (7.94x10^-6)²/2.5-(7.94x10^-6)
Ka= (7.94x10^-6)²/2.4999
Ka= 2.52x10^-11.
Was a Fun One
The ionization constant of this weak acid is [tex]2.52*10^{-11}[/tex]. The values can be substituted in dissociation formula.
What information do we have?
Molarity of acid=2.5M
pH=5.1
To find:
ka=?
Calculation of ionization constant:[tex]HA + H_2O < === > H_3O^+ + A^-[/tex]
The value of dissociation constant will be:
[tex]Ka =[H_3O^+] [A^-]/ {HA][/tex]
The Moles of A- and H3O+ are in 1:1.Their concentrations at equilibrium will be the same.
[tex]Ka= x.x/2.5-x\\\\Ka= x^2/2.5-x\\\\pH= -log (H_3O^+)\\\\H_3O^+ = 10^{-pH}\\\\x=10^{-5.1}\\\\x=7.94*10^{-6}[/tex]
[tex]Ka= x^2/2.5-x\\\\Ka= (7.94*10^{-6})^2/2.5-(7.94*10^{-6})\\\\Ka= (7.94*10^{-6})^2/2.4999\\\\Ka= 2.52*10^{-11}\\\\[/tex]
Thus, ionization constant of this weak acid is [tex]2.52*10^{-11}[/tex].
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In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: g
The question is incomplete. The complete question is :
In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.
Solution :
Consider the equation of the reaction between NaOH and [tex]$HCl$[/tex]
NaOH (aq) + HCl (aq) → NaCl(aq) + [tex]$H_2O (l)$[/tex]
The above equation tells us that [tex]$1 \text{mole}$[/tex] of [tex]$NaOH$[/tex] reacts with [tex]$1 \text{mole}$[/tex] of [tex]$HCl$[/tex].
So at the equivalence point, the moles of NaOH added = moles of [tex]$HCl$[/tex]present.
If the volume of the [tex]$HCl$[/tex] taken = [tex]$V_1$[/tex] mL and the conc. of [tex]$HCl$[/tex] = [tex]$M_1$[/tex] mole/L
The volume of NaOH added up to the color change = [tex]$V_2 \text{ and conc of NaOH = M}_2$[/tex] mole/L
Moles of [tex]$HCl$[/tex] taken = [tex]$V_1 \ mL \times M_1 \ mol/100 \ mL = V_2M_2 \times 10^{-3}$[/tex] moles.
The color change will occur when the moles of NaOH added is equal to the moles of [tex]$HCl$[/tex] taken.
Thus when [tex]$V_1 M_1 \times 10^{-3} = V_2M_2 \times 10^{-3}$[/tex]
or when [tex]$V_1M_1 = V_2M_2$[/tex]
or [tex]$V_2=\frac{V_1M_1}{M_2}$[/tex] mL of NaOH added, we observe the color change.
Where [tex]$V_1, M_1$[/tex] are the volume and molarity of the [tex]$HCl$[/tex] taken.
[tex]$M_2$[/tex] is the molarity of NaOH added.
When both the NaOH and [tex]$HCl$[/tex] are of the same concentrations, i.e. if [tex]$M_1=M_2$[/tex], then [tex]$V_2=V_1$[/tex]
Or the 40 mL of [tex]$HCl$[/tex] will need 40 mL of NaOH for a color change and
30 mL of [tex]$HCl$[/tex] would need 30 mL of NaOH for the color change (provided the concentration [tex]$M_1=M_2$[/tex])
Plz help me well mark brainliest if correct
Answer:
D) biodiversity
Explanation:
the answer is D) biodiversity
What kind of reaction is this ? P+02
-
P4010
O Synthesis
O Decomposition
O Single Replacement
O Double Replacement
Answer:
Synthesis reaction
Explanation:
To know which option is correct, it important that we know what each option represents.
Synthesis reaction is a reaction in which two different elements react to form a single compound. For example
X + Y —> XY
Decomposition reaction is a reaction in which a compound splits into two or more simpler substance. For example
XY —> X + Y
Single Replacement reaction is a reaction in which one element replaces or displaces another element from a compound. For example
X + YZ —> XZ + Y
Double Replacement reaction is a reaction in which the parts of two ionic compounds exchange their ions to form a new compound. For example
WX + YZ —> WZ + YX
Now, considering the equation given above i.e
P + O₂ —> P₄O₁₀
We can see that P and O₂ reacted to produce a new compound (i.e P₄O₁₀).
Thus, the reaction is a synthesis reaction because two different elements (i.e P and O₂) reacted to form a single compound (i.e P₄O₁₀).
sodium is an inactive metal why
Answer:
Inactive metals are inert metals that doesn’t react with most of the chemicals.They are highly resistant to oxidation and corrosion when exposed to moisture.
Explanation:
A chemistry student needs 30.0 g of acetic acid for an experiment. He has available 1.2 kg of a 7.58% w/w solution of acetic acid in acetone.
Calculate the mass of solution the student should use. If there's not enough solution, press the "No solution" button.
Round your answer to 3 significant digits.
Answer:
The mass of solution will be "395.78 g".
Explanation:
Given:
Mass of acetic acid,
= 30 g
Percentage,
= 7.58% w/w
Now,
⇒ % [tex]=\frac{Mass \ of \ acetic \ acid}{Mass \ of \ solution}\times 100[/tex]
By putting the values, we get
⇒ [tex]7.58=\frac{30}{Mass \ of \ solution}\times 100[/tex]
⇒ [tex]Mass \ of \ solution=\frac{30\times 100}{7.58}[/tex]
⇒ [tex]=\frac{3000}{7.58}[/tex]
⇒ [tex]=395.78 \ g[/tex]
How many total ions are there in 5.00 moles of cobalt (II) bromide?
"When your heart was an open book" is an example of of
A. simile
B. metaphor
C. alliteration
D. all of the above
B. metaphor
The answer is metaphor, because it can't possibly be other thing.
A solution is prepared by dissolving solid ammonium nitrate, NH4NO3, in water. The initial temperature of the water was 25oC, but after the solid had dissolved, the temperature had fallen to 20oC. What conclusion may be made about delta H and delta S
Answer:
ΔH is positive, ΔS is positive
Explanation:
The enthalpy of reaction (ΔH) is positive in an endothermic reaction. An endothermic reaction leads to a decrease in temperature. Hence the fact that the temperature was decreased from 25oC to 20oC shows that the reaction is endothermic therefore ΔH is positive.
Also, the equation of the dissolution is;
NH4NO3(s) -----> NH4^+(aq) + NO3^-(aq)
This means that the number of particles in solution were increased. The entropy increases with increase in number of particles hence ΔS is positive.