Answer:
Balance the following chemical equations:
Explanation:
2N2 + O2 → 2N2O
A gas at -20c occupies volume 140 ml calculate temperature at which the volume of the gas becomes 65 ml pressure constant
Answer:
–156 °C
Explanation:
The following data were obtained from the question:
Initial temperature (T1) = –20 °C
Initial volume (V1) = 140 mL
Final volume (V2) = 65 mL
Final temperature (T2) =?
Pressure = constant.
Next, we shall convert –20 °C to Kelvin temperature. This can be obtained as follow:
T(K) = T(°C) + 273
Initial temperature (T1) = –20 °C
Initial temperature (T1) = –20 °C + 273 = 253 K.
Next, we shall determine the new temperature of the gas as follow:
Initial temperature (T1) = 253 K
Initial volume (V1) = 140 mL
Final volume (V2) = 65 mL
Final temperature (T2) =?
V1/T1 = V2/T2
140/253 = 65/T2
Cross multiply
140 × T2 = 253 × 65
140 × T2 = 16445
Divide both side by 140
T2 = 16445 /140
T2 = 117 K
Finally, we shall convert 117 K to celcius temperature. This can be obtained as follow:
T(°C) = T(K) – 273
T2 = 117 K
T2 = 117 K – 273
T2 = –156 °C
Thus, the new temperature of the gas is –156 °C
Determine the molarity of a solution prepared by dissolving 0.198 g of "KHP" (C8H5O4K) in enough water to make 125 mL of solution.
When the solution is found and titrated with aqueous sodium hydroxide, the endpoint is reached after the addition of 27.80 mL of base solution. How many moles of NaOH reacted? What is the concentration of the NaOH?
Answer:
0.007756M KHP; 0.0009695 moles NaOH reacts; 0.03488M NaOH.
Explanation:
Potassium hydrogen phthalate, KHP, is a salt used as standard to determine concentration of basic solutions as NaOH solutions.
To find molarity of the KHP solution we need to convert mass of KHP to moles and divide this in 125mL = 0.125L:
Moles KHP -Molar mass: 204.22g/mol-:
0.198g * (1mol / 204.22g) = 0.0009695 moles KHP
Molarity:
0.0009695 moles KHP / 0.125L = 0.007756M KHP
NaOH reacts with KHP as follows:
NaOH + KHP → Na⁺ + KP⁻ + H₂O
That means 1 mole of NaOH reacts per mole of KHP, that means moles of NaOH that reacts are = Moles of KHP added:
0.0009695 moles NaOH reacts
In 27.80mL = 0.02780L the NaOH was contained. Molarity is:
0.0009695 moles NaOH / 0.02780L =
0.03488M NaOH
Moles of NaOH added will be "0.034".
According to the question,
→ [tex]Molarity = \frac{Number \ of \ moles}{Volume}[/tex]
By substituting the values, we get
[tex]= \frac{0.198}{204}\times \frac{1000}{125}[/tex]
[tex]= 0.0077 \ M[/tex]
Let,
The number of moles added be "[tex]M_2[/tex]".Now,
→ [tex]M_1 V_1 = M_2 V_2[/tex]
→ [tex]0.0077\times 125=M_2\times 27.8[/tex]
→ [tex]M_2 = 0.034 \ moles[/tex]
Thus the above answer is appropriate.
Learn more:
https://brainly.com/question/23931328
Consider the following reaction:2 HgCl2(aq) + C2O42-(aq) 2 Cl-(aq) + 2 CO2(g) + Hg2Cl2(s)(a) The rate law for this reaction is first order in HgCl2(aq) and second order in C2O42-(aq). What is the rate law for this reaction?Rate = k [HgCl2(aq)] [C2O42-(aq)]Rate = k [HgCl2(aq)]2 [C2O42-(aq)]Rate = k [HgCl2(aq)] [C2O42-(aq)]2Rate = k [HgCl2(aq)]2 [C2O42-(aq)]2Rate = k [HgCl2(aq)] [C2O42-(aq)]3Rate = k [HgCl2(aq)]4 [C2O42-(aq)](b) If the rate constant for this reaction at a certain temperature is 0.0169, what is the reaction rate when [HgCl2(aq)] = 0.158 M and [C2O42-(aq)] = 0.202 M?Rate = M/s.(c) What is the reaction rate when the concentration of HgCl2(aq) is doubled, to 0.316 M while the concentration of C2O42-(aq) is 0.202 M?Rate = M/s
Answer:
b
Explanation:
Which process is shown in the diagram?
0,
ing
CO, +H,0
Chloroplast
Mitochondrion
Sugar
Heat
o
ATP
Respiration
The cellular respiration process, which generates ATP as the final result, employs oxygen and sugar as reactants. So, the correct option is A.
What is Cellular respiration?Cellular respiration is the process by which organisms combine oxygen with food molecules, channeling the chemical energy from those resources into life-sustaining activities while eliminating carbon dioxide and water as waste.
Both oxygen and glucose are reactants in the mobile respiratory system. ATP is the primary component of mobile respiration; waste products include carbon dioxide and water.
Oxygen might be present or absent while cells are respiring. Nonetheless, the activity is essentially known as "cellular respiration" because the cell seems to "respire" by consuming molecular oxygen (as an acceptor of electron) and exhaling carbon dioxide (as an end product).
Therefore, the correct option is A.
Learn more about Cellular respiration, here:
https://brainly.com/question/29760658
#SPJ7
Your question is incomplete, most probably the complete question is:
The process shown in the diagram produces oxygen and sugar. Which
process uses oxygen and sugar as reactants?
Chloroplast
Mitochondrion
Sugar
CO, +H,0
ATP
Heat
Respiration
A. Cellular respiration
B. Water cycle
c. Transpiration
D. Photosynthesis
Calculate the final temperature (once the ice has melted) of a mixture made up initially of 70.0 mL liquid water at 28 oC and 5.0 g ice at 0.0 oC.
Answer:
21.52° C
Explanation:
From the given information:
mass of the liquid water = 70.0 mL
Initial temperature = 20°C
mass of the ice = 5.0 g
temperature of ice = 0.0°C
Using the calorimetric function:
heat lost by water = heat gained by ice.
mass of water × specific heat of water (s) × ΔT = mass of ice × specific heat of ice (s) × ΔT + n (ΔH_fusion}
⇒ 70 × 4.184 × (28 -x) = 5 × 2.108(x - 0) + [tex](\dfrac{5}{18})[/tex] × 6.01 × 10³
By solving the above equation,
x = 21.52° C
The final temperature of the mixture of water and ice is 21.5 ⁰C.
The given parameters;
initial volume of the liquid = 70 mL initial temperature of the water, = 28⁰Cmass of the ice, = 5.0 gtemperature of the ice, = 0⁰ Cspecific heat capacity of ice = 2.09 J/g ⁰Cheat of fusion of ice = 333.55 J/gspecific heat capacity of water = 4.184 J/g⁰ Cdensity of water = 1 g/mlLet the final temperature of the mixture = t
mass of the liquid water = 1 g/ml x 70 ml = 70 g
Apply the principle of conservation of energy to determine the final temperature of the mixture;
heat lost by water = heat gained by ice
[tex]70 \times 4.184(28 - t) = 5\times 2.09(t - 0) \ + \ 5 \times 333.55\\\\8200.64 - 292.88t = 10.45 t + 1667.75\\\\303.33t = 6532.89\\\\t = \frac{6532.89}{303.33}\\\\t = 21.5 \ ^0C[/tex]
Thus, the final temperature of the mixture of water and ice is 21.5 ⁰C.
Learn more here:https://brainly.com/question/12200172
A compound of copper and sulfur contains 76.84 g of metal and 38.53 g of nonmetal. How many grams of copper are in 3801 kg of the compound? How many grams of sulfur?
Answer:
There are:
2'531,500 g Cu1'269,500 g SExplanation:
First calculate the percentage of Cu and S in the compound:
Total mass = 76.84 g + 38.53 g = 115.37 g% metal (Cu) = 76.84/115.37 * 100% = 66.6%% metal (S) = 38.53/115.37 * 100% = 33.4%These percentages will remain the same no matter how much of the compound we analyze.
Now we calculate the grams of Cu and S in 3801 kg of the compound:
kg Cu = 3801 kg * 66.6/100 = 2531.5 kg Cug Cu = 2531.5 kg * 1000 = 2531500 g Cukg S = 3801 kg * 33.4/100 = 1269.5 kg Sg S = 1269.5 kg * 1000 = 1269500 g SWhich is the best example and explanation that a physical change has occurred?
fireworks exploding, because energy is released as light and heat
gasoline burning, because it forms water vapor and carbon dioxide
O crushing an ice cube, because the chemical structure of the ice cube is changed
dicing potatoes, because the molecules are separated but remain the same substance
dicing potatoes, because the molecules are separated but remain the same substance
Answer:
For the people wondering, yes, dicing potatoes is the correct answer. Because a new substance has not formed.
A 45.0 mL solution of 0.0450 M hydroxylamine is extracted with 125 mL of solvent. The distribution constant for the reaction is 5.00 and the pKa of the protonated form of hydroxylamine is 5.960. Calculate the concentration of hydroxylamine remaining in the aqueous phase at pH=4.50 and pH=6.50 .
Answer:
pH = 4.5, concentration = 0.045 M.
pH = 6.5, concentration = 0.175 M.
Explanation:
The ka for the can be calculated by using the formula below;
Ka = 10^-pka = 10^-5.960 = 1.1 × 10^-6
The concentration of hydrogen ion at pH = 4.50 can be calculated as given below;
{H^+ } = 10^-4.50 = 3.2 × 10^-5 M.
(NB=> 10 in this regards means the inverse of log).
The next step is to determine the distribution coefficient which can be calculated by using the formula below;
distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).
distribution coefficient =( 5 × 1.1 × 10^-6 ) / 1.1 × 10^-6 + 3.2 × 10^-5 M. = 5.5 × 10^-6/ 3.2 = 0.00000171875
The fraction remaining from the compound = 45.0 mL / 45.0 mL + (0.00000171875 × 125).
= 0.999995.
Thus, the concentration at pH = 4.5 = 0.999995 × 0.0450 M = 0.045 M
(B). pH=6.50, thus the concentration of Hydrogen ion = 10^-6.5 = 3.2 × 10^-7 M.
distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).
distribution coefficient = (5 × 1.1 × 10^-6)/ 1.1 × 10^-6 + 3.2 × 10^-7 M).
distribution coefficient = 5.5 × 10^-6/ 1.42 × 10^-6 = 3.9.
Therefore, the concentration = 3.9 × 0.0450 M = 0.175 M.
The nucleus of an atom is made up of which of the following combinations of particles?
Answer: Atoms of different elements are found to have different number of protons, neutrons, and electrons. To distinguish one atom from another or to classify the various atoms, a number which indicates the number of protons in the nucleus of a given atom, is assigned to the atoms of each identified element. This number is known as the atomic number of the element. The atomic numbers for some of the elements which are associated with the study of semiconductors are given in the following table.
Explanation:
Element Symbol Atomic Number
Silicon Si 14
Germanium Ge 32
Arsenic As 33
Antimony Sb 51
Indium In 49
Gallium Ga 31
Boron B 5
Answer:
[tex]\boxed {\boxed {\sf Protons \ and \ neutrons}}[/tex]
Explanation:
The atom is made up of two main parts: the nucleus and the electron cloud.
The nucleus is the center and has two subatomic particles: the protons (positive charge) and the neutrons (no/neutral charge). The nucleus as a whole has a positive charge, since the neutrons don't provide a charge.
The electron cloud surrounds the nucleus and houses the negatively charged electrons in a "cloud" of energy levels.
So, the nucleus of the atom is made up of protons and neutrons.
A competitive high school swimmer takes 56.7 seconds to swim 100. yards. What is his rate in m/min?
m
min
Answer:
96.72 m/min
Explanation:
The following data were obtained from the question:
Time (t) = 56.7 s
Distance (d) = 100 yard
Rate (R) =?
Next, we shall convert 56.7 s to minutes. This can be obtained as follow:
60 s = 1 min
Therefore,
56.7 s = 56.7 s × 1 min /60 s
56.7 s = 0.945 min
Next, we shall convert 100 yard to metre (m). This can be obtained as follow:
1 yard = 0.914 m
Therefore,
100 yard = 100 yard × 0.914 m /1 yard
100 yard = 91.4 m
Finally, we shall determine the rate of the swimmer as follow:
Time (t) = 0.945 min
Distance (d) = 91.4 m
Rate (R) =?
R = d/t
R = 91.4/0.945
R = 96.72 m/min
Thus the rate of the swimmer is 96.72 m/min
Plz what’s the answer to this
Answer: E
Explanation:hope this helps you out
H20+ SO3 ? Which compound is likely produced by the chemical reaction?
Answer:
h2so4
Explanation:
im big brain.
What does this passage explain about people?
why mothers favor some children over others
the contrasting sides of human nature
why there is harmony in all things
left- and right-handedness
Answer:
the contrasting sides of human nature
Explanation:
I took the test
do seeds need energy to germinate
Answer:
Seeds need oxygen so that they can produce energy for germination and growth. The embryo gets energy by breaking down its food stores. Like all organisms, this is done through a process known as aerobic respiration. —a series of reactions where energy is released from glucose, using oxygen.
Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O (2) HNO3, H2SO4 (3) Br2, FeBr3 What is the final product of this sequence?
Answer:
See image attached
Explanation:
The reaction of toluene with alkaline potassium permanganate in the presence of heat leads to the oxidation of the -CH3 to give benzoic acid.
Reaction benzoic acid with HNO3/H2SO4 yields the nitronium ion (NO2+).
Recall that -COOH is a metal director and deactivated the ring towards electrophilic substitution hence the m-nitrobenzoic acid is formed.
Reaction with FeBr3/Br2 yields the product shown in the image attached.
When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as shown in the netionic equation below. The initial temperature of both solutions is 23.0°C. Assuming that the reaction goes tocompletion, and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ∙°C), calculatethe final temperature of the solution.Ca2+(aq) + 2 F-(aq) → CaF2(s)∆H°=-11.5 kJ
Answer:
23.55°C
Explanation:
Based on the equation:
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
When 1 mole of Ca²⁺ and 2 of F⁻ reacts, 11.5kJ are released.
Thus, we need to find moles of reaction to find the heat released and using:
C = SₓmₓΔT
We can find the final temperature as follows:
Moles of reaction:
0.0500L * (0.400mol / L) = 0.0200moles Ca²⁺ = Moles of reaction
Heat produced is:
0.0200 moles * (11.5kJ / mol) = 0.23kJ
Using:
C = SₓmₓΔT
Where C is heat = 230J
S is specific heat = 4.18J/g
m is mass of solution = 100.00g
And ΔT is change in temperature
230J = 4.18J/gₓ100.00gₓΔT
ΔT = 0.55°C
As initial temperature is 23.0°C
Final temperature = 23.0°C + 0.55°C =
23.55°CThe final temperature of the solution is 23.55°C.
We were given the equation
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
This means that 1 mole of Ca²⁺ and 2 of F⁻ reacts to form CaF₂ and 1.5kJ is released.
The formula we need to use is C = SₓmₓΔT
where c is heat, s is specific heat, m is number of mole and ΔT is temperature change.
We need to find the moles of reaction first
Moles of reaction = 0.0500L × (0.400mol / L) = 0.0200moles Ca²⁺
Heat produced = 0.0200 moles ×11.5kJ / mol = 0.23kJ
We can then substitute into the formula
C = SₓmₓΔT
C = 230J
S = 4.18J/g
m = 100.00g
ΔT= ?
230J = 4.18J/gₓ100.00gₓΔT
= 0.55°C
Since the initial temperature is 23.0°C
The Final temperature will be 23.0°C + 0.55°C
=23.55°C
Read more on https://brainly.com/question/19564028
Calculate the internal energy of a system (in kiloJoules) that absorbs 14.73 kJ while being compressed with a pressure of 1.54 atm from 5.72 L to 1.0 L. Answer to one decimal space.
The internal energy of a system : 21.9 kJ
Further explanationThe laws of thermodynamics 1 state that energy can be changed but cannot be destroyed or created
The equation is:
ΔU=Q+W
Energy owned by the system is expressed as internal energy (U)
The sign rules for heat and work are set as follows:
• The system receives heat, Q +
• The system releases heat, Q -
• The system does work, W -
• the system accepts work, W +
The system absorbs 14.73 kJ⇒Q=+14.kJ
The system compressed⇒work done on the gas⇒W=+
W=-PΔV
[tex]\tt W=-1.54(1-5.720)\\\\W=7.2688[/tex]
[tex]\tt internal~energy(\Delta U)=Q+W\\\\\Delta U=14.73+7.2688\\\\\Delta U=21.9[/tex]
Which of the following statements correctly describes the function of cell parts?
A. The cell membrane determines which type of cell will develop.
B. The nucleus contains all the nutrients that the cell needs.
C. The mitochondria are the power plants of the cell.
D. The genes contain hemoglobin.
The statements correctly describes the function of cell parts is the mitochondria are the power plants of the cell. Therefore, option C is correct.
What do you mean by the mitochondria ?The cytoplasm of a cell contains tiny structures (fluid that surrounds the cell nucleus). The majority of a cell's energy is produced by mitochondria, which also have unique genetic material distinct from that present in the nucleus.
Oxidative phosphorylation, which produces ATP using the energy generated during the oxidation of the food we ingest, is the traditional function of mitochondria.
For the majority of biochemical and physiological activities, including growth, mobility, and equilibrium, ATP is used as the main energy source in turn.
Thus, option C is correct.
To learn more about the mitochondria, follow the link;
https://brainly.com/question/10688306
#SPJ6
A hutch weighs 150 lbs and it’s base has a length and width of 15 in and 34 in, respectively. What is the pressure exerted by the hutch on the floor?
Answer:0.29
Explanation:
To determine the pressure of the hutch on the floor, we must first calculate the area of the base of the hutch.
A=lw=(15in.)(34in.)=510in.2
We can now use the formula to calculate pressure.
P=FAP=150lbs510in.2P≈0.294lbin.2
Rounding to two significant figures, the pressure exerted by the hutch on the floor is 0.29lbin.2.
How many seconds are in 100 years(factor label conversion)
Answer:
0.0166
Explanation:
This conversion of 100 seconds to minutes has been calculated by multiplying 100 seconds by 0.0166 and the result is 1.6666 minutes.
I hope this helps,
even a little bit
Write a balanced half-reaction for the oxidation of gaseous nitric oxide (NO) to aqueous nitrous acid (HNO2) in acidic aqueous solution.
Answer:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
Step-by-step explanation:
NO ⇒ oxidation number of N = +2
HNO₂ ⇒ oxidation number of N= +3
Therefore, NO has to lose 1 electron to be oxidized to HNO₂. We write the half-reaction with 1 electron (1 e-) in the products side.
NO → HNO₂ + 1 e-
Now, we have 0 electrical charges in the reactants side, and a total of -1 electrical charge in the products side. As the reaction is in acidic aqueous solution, we have to add H⁺ ions to balance the charges. We perform the balance by adding 1 H⁺ (positive charge) to neutralize the negative charge in the side of the products:
NO → HNO₂ + 1 e- + 1 H⁺
Now, we perform the mass balance. We have:
N: 1 atom in both sides
O: 1 atom in reactants side and 2 atoms in products side
H: 0 atoms in reactants side, 2 atoms in products side.
Thus, we have to add 1 H₂O molecule to the reactants side to equal the masses:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
Finally, the oxidation half-reaction is:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
Suppose there is a gaseous mixture of nitrogen and oxygen. If the total pressure of the mixture is 480 mmHg, and the partial pressure of nitrogen is 290 mmHg, calculate the partial pressure of oxygen in the mixture using Dalton's law.
Answer:
Partial pressure of oxygen = 190 mmHg
Explanation:
From the question;
Mixture contains only nitrogen and oxygen
Total pressure of the mixture = 480 mmHg
Partial pressure of nitrogen = 290 mmHg
Dalton's law states that the pressure of a system is as a result of the sum of the partial pressures of the individual components of the mixture. This means that in this mixture;
Pressure of mixture = Partial Pressure of Nitrogen + Partial Pressure of Oxygen
480 = 290 + Partial pressure of oxygen
Partial pressure of oxygen = 480 - 290
Partial pressure of oxygen = 190 mmHg
The properties of compund are different from the properties of their constituenr
Answer: Atoms of carbon and hydrogen
Explanation:
write the chemical formula of tetraphosporus osctasulfide
Answer:
P4S8 .
the chemical formula of Tetraphosporus osctasulfide is p4S8
In a titration, you start with 0.05 M sodium hydroxide (NaOH) and slowly add it to 40 mL of HC1 with an unknown concentration. What is the original concentration of the HC1 if you add a total of 15.4 mL of sodium hydroxide to the HC1 to achieve pH =7?
Answer:
The original concentration of the HCl is: 0.01925 M
Explanation:
Equation:
HCl+NaOH-------> NaCl+H₂O
Volume of NaOH added = 0.05 M
No of moles of NaOH = 15.4 mL [tex]x\frac{1 L}{1000 mL} x\frac{0.05 mol NaOH}{L}[/tex]
= 0.00077 mol NaOH
Then,
Volume of HCl solution = 40 mL x 1/1000 mL
= 0.0400 L
Therefore,
Concentration of HCl = 0.00077 mol/0.0400 L
= 0.01925 M
Now, to find the pH:
pH = -log₁₀[H⁺]
= -log₁₀(2x10⁻⁶)
= 5.7
Balance the following equations ___Fe + __O2= ___Fe3O4
What name is given to the elements that appear in the right-most column of the periodic
table?
- Alkali metals
- Alkaline earth metals
- Transition metals
- Noble gases
(NOBLE GASES IS ANSWERR)
Answer:
Noble gases... (You already know...)
Explanation:
The right-most column of the periodic table contains atoms with full electron shells, also known as Noble Gases.
Hope this helped!
Answer:
Noble gases
Explanation:
The six elements listed in the last column of the table (Group 18) of the periodic table are collectively referred to as the noble gases. All of the noble gases have the maximum number of electrons possible in their outer shells (two electrons in helium’s outer shell, and eight electrons for all the others), making them stable.
List any three quantum numbers that describe an electron in an atom and state the relationship between any of the two
Explanation:
To completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms).
Please follow me and make me Brainless
The chart shows the frequencies of certain colors of visible light. A 2 column table with 4 rows. The first column is labeled light with entries red, violet, green, orange. The second column is labeled frequency in hertz with entries 4.5 times 10 Superscript 14 baseline, 7.5 times 10 Superscript 14 baseline, 6.0 times 10 Superscript 14 baseline, 5.0 times 10 Superscript 14 baseline. Which colors will eject electrons when they strike sodium, which has a frequency threshold of 5.7 × 1014 Hz? violet and green red and orange violet only red, violet, green, and orange
Answer:
Violet only
Explination:
Violet is the only color that will eject electrons when it strikes sodium.
The colors that will eject electrons when there's a strike with sodium from the chart will be A. Violet and green.
ElectronsFrom the complete information, William made a chart in order to illustrate the result of the experiment that was made with the photoelectric effect.
In this case, the colors that will eject electrons when they strike sodium, with the frequency threshold will be violet and green.
This was gotten from the result that the frequencies of light were lower than the frequency threshold.
Learn more about electrons on:
https://brainly.com/question/860094
12oz of water initially at 75oF is mixed with 20oz of water intiially at 140oF. What is the final temperature?
Answer:
[tex]115.625^{\circ}\text{F}[/tex]
Explanation:
[tex]m_1[/tex] = First mass of water = 12 oz
[tex]m_2[/tex] = Second mass of water = 20 oz
[tex]\Delta T_1[/tex] = Temperature difference of the solution with respect to the first mass of water = [tex](T-75)^{\circ}\text{F}[/tex]
[tex]\Delta T_2[/tex] = Temperature difference of the solution with respect to the second mass of water = [tex](T-75)^{\circ}\text{F}[/tex]
c = Specific heat of water
As heat gain and loss in the system is equal we have
[tex]m_1c\Delta T_1=m_2c\Delta T_2\\\Rightarrow m_1\Delta T_1=m_2\Delta T_2\\\Rightarrow 12(T-75)=20(140-T)\\\Rightarrow 12T-900=2800-20T\\\Rightarrow 12T+20T=2800+900\\\Rightarrow 32T=3700\\\Rightarrow T=\dfrac{3700}{32}\\\Rightarrow T=115.625^{\circ}\text{F}[/tex]
The final temperature of the solution is [tex]115.625^{\circ}\text{F}[/tex].