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reaction between A(g) and X(g). What is the amount of heat released when 10 mol of A(g) reacts with an excess X(g) ?
ΔH
A -236kJ
X -136kJ
Y -167kJ
Using the heats of formation found in the table above, calculate ΔH for the reaction below.
6A(aq) + 7X(g) → 6Y(l)
Y + 2X → 4Z ΔH=-4
A + 3B → 2Z ΔH=-2
A → X +C ΔH=7
Using the thermodynamic data above, determine ΔH for the reaction below.
2C+ 6B → Y
When 0.3 moles of A(s) (4 grams) is dissolved in 12 grams of water at 23°C, the temperature of the water increases to 31°C. The specific heat of water is 4.18 J/g°C.
Calculate ΔH in kJ/mol. Report your answer to 1 decimal place.

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titrated with a 0.200 M solution of the base, LiOH.
Write the balanced chemical reaction for neutralization reaction:
HClO4 (aq) + LiOH (aq) → LiClO4 (aq) + H2O (l)
Write the NET ionic equation for the neutralization reaction.
OH⁻ (aq) + H⁺ (aq) → H2O (l)
Compute the pH of the titration solution. Show your work
i) before any of the base is added
ii) after 25. mL of base is added
iii) after 50. mL of base is added
A student performs the titration with the same chemicals but with smaller volumes of each chemical . Which of the following titration curves could represent the titration. Explain
A because this entails a strong acid and a strong base.
Question 2
A student performs a titration of an unknown acid with a strong base and gets the following titration curve:
a) The student consults the list of pKa of acids shown below. If the acid is listed in the table below, which is the most likely identity of the unknown acid? Explain.
Acid
Ka
HF
7.2 x 10-4
CH3COOH
1.8 x 10-5
H2CO3
4.3 x 10-7
HBrO
2.0 x 10-9
The unknown acid is HBrO because the calculated Ka is in between 50^-4 and 50^-6 and 2.0 x 10^-9 lies in between them.
b) What is the initial molarity of the acid?
10^-3 = 0.001M
Question 3
a) Describe the components and the composition of an effective buffer solution. Explain how the components of the buffer allow the buffer to maintain its pH.
An effective buffer solution has a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer solution is most effective when the ratio of its component concentrations is close to 1, also when the pH is equal to the pka of the acid.; The components of the buffer allow the buffer to maintain its pH because buffers can absorb excess H+ions or OH– ions.
An employer is interviewing four applicants for a job as a laboratory technician and asks each how to prepare a buffer solution with a pH of 5.0. The following constants may be helpful: hydrazoic acid, pKa = 4.74 Boric acid, pKa = 9.23
Archita A. says she would mix equal molar solutions of hydrazoic (HN3) and sodium azide (NaN3) solutions.
Bradley B. says she would mix equimolar Boric acid (H3BO3) and HCl solutions.
Carlos C. says he would mix equimolar Boric Acid (H3BO3) and sodium dihydrogen borate (NaH2BO3) solutions.
Delia D. says he would mix equimolar hydrazoic Acid (HN3) and NaOH solutions.
b) Which of these applicants has given an appropriate procedure? Explain your answer
Delia because she is using Sodium hydroxide which results in a pH of 5. NaOH is a strong base and in order to have an effective buffer a weak acid must be incorporated which is the HN3.
c) Explain what is wrong with the erroneous procedures.
The rest all incorporate a strong acid and a strong base or a weak acid and a weak base which don’ result in an effective buffer.
d) The applicants have access to the 1 Liter volumes of each of the solutions listed above. They have access to graduated cylinders. In order to make 1.0 Liter of the correct 5.0 buffer solution, what volumes of the two chemicals must be mixed?

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3.The GREY CUP (Canadian Football) is played on a rectangular field. The area (A, in m2) of the field ...

is given by the equation , where x is the width of the rectangle in metres. A= -x2 + 10x
Make a table of values for this relation in the chart below.

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Your answer should be written in slope-intercept form.
P(0, 0), x = −4y − 18

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5.At a price of $1.04 per roll, the supply of toilet paper in a large town is 25,000 rolls, and ...

mand is 18,200 rolls. When the demand increases to 26,200 rolls, the supply is 20,000 and the price is $1.24 per roll. Let x be the quantity in thousands of rolls. The table below gives the price-supply and price-demand equations.
Price Equations for Toilet Paper
Type Equation
Price-Supply P = -0.04x + 2.04
Price-Demand P = 0.025x + 1.495
QUESTION 1
Find the supply at a price of $2 per roll.
1000 rolls
10,000 rolls
1 roll
5000 rolls
QUESTION 2
Find the demand at a price of $2 per roll.
20.2 rolls
202 rolls
20,200 rolls
500 rolls
QUESTION 3
Use the substitution method to find the equilibrium quantity. Round x to the nearest tenth first and then convert to thousands. Include the units in your answer.
QUESTION 4
What is the equilibrium price? Write the answer in dollars and cents, rounding to the nearest cent.

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terms of a and b.
(ii) Explain why a ≠ -3/4b '
(
b) A cylinder has a length equal to 3 times its diameter. Find the total area of the
cylinder as a function of its radius.

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units.
Chemical Equation: Write a generic chemical equation for the dehydration of cobalt (II) chloride ∙ x hydrate (include the state symbols of the reactant and two products). [T2]
Mass of Reactants and Products:
a) Calculate the initial mass of the hydrated cobalt (II) chloride. [T1]
b) Calculate the final mass of the anhydrous cobalt (II) chloride remaining in the cruiio8icible. [T1]
c) Calculate the mass of water given off by the sample of hydrated cobalt (II) chloride. [T1]
Moles of Products:
a) Calculate the moles of anhydrous cobalt (II) chloride remaining in the crucible. [T1]
b) Calculate the moles of water released from the hydrate. {T1]
4. Mole Ratio
a) Create an experimental mole ratio between the b) and a). [T1]
5. Formula of Hydrate: State the chemical formula you have determined for this hydrate.
Round the formula to the closest whole number value for x. [T1]
Discussion/Conclusion Questions: [T6]
Based on the chemical formula of the hydrate, calculate the percentage composition (percent by mass) of the hydrated cobalt (II) chloride. Remember to determine the percentage of each element (Co, Cl, H, and O). [T2]
A possible source of systematic error in this experiment is insufficient heating. Suppose that the hydrate was not completely converted to the anhydrous form. Describe how this would affect: the calculated percent by mass of water and the experimental molecular formula (i.e. would x be higher, lower or the same).
Suppose a student spilled some of the hydrated cobalt (II) chloride. Describe how this would affect the calculated percent by mass of water (would it be higher, lower or the same) and the experimental chemical formula of the hydrate. [T2]

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bottom of the roof lie on the x-axis. The equation of the function describing the cross-section is h(x)=-|6x|+7, where h is the height of the roof, in metres, and x is the horizontal distance from the centre of the roof, in metres. To the nearest tenth of a metre, what is the width of the bottom of the roof?

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countered (unidirectional flow or parallel flow). The planer walls and the fluids are initially at rest. Lower plate moves to left and upper plate to right. Let the fluids be an oil, where kinematic viscosity (ν) = 2.17 x 10-4m2/s and the distance between both plate (h) is 10 mm. U0 = 0.4 m/s I need to find the governing equation, boundary conditions, initial conditions and to derive velocity distribution in steady state.
Also, Use FTCS explicit method to calculate the velocity distribution as a function of time by implementing these governing equation in Matlab

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Use your result in (a) to solve the system:
■(x&+2y&+z&=1@x&y&+2z&=2@x&+y&+2z&=3)
Question#2 (5) (modified from #13 p. 102 in your book)
Solve the matrix equation for X
X[■(1&1&1@1&2&0)]=[■(1&1&1@3&4&2)]
Question#3 (5) (modified from #9 p. 102 in your book) Let
[■(a&0&b&2@0&a&3&6@0&a&b&c+2)] be the augmented matrix of a linear system.
Find for what values of a,b,c the system has:
(i) a unique solution
(ii) a one-parameter solution
(iii) a two-parameter solution
iv) no solution
Question#4 (7) Write the matrix A=[■(-1&1&-1@1&1&-1@1&-1&2)] as a product of elementary matrices
Question#5 (3) Find the determinant by any method:
|■(0&-1&0&0&1@1&1&1&3&1@1&2&3&1&2@1&-1&0&3&1@1&-1&1&0&1)|
Question#6 (3-2)Given thissystem:
■(x_1&+2x_2&+x_3&=1@x_1&-〖3x〗_2&+0x_3&=2@x_1&+0x_2&+2x_3&=3)
a) Use Cramer’s method to solve for x_1 only
b) Solve for the other variables by any method.

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seen an equation of a circle this is moved in both the x and y direction be converted to a polar equation.
For example, I know that the equation of a circle x^(2)+(y-2)^(2)=4 is r=4sin(theta) when converted to polar. Same thing for a translation with the x variable. However, I have never seen, nor do I know how to do, a conversion of a circle with both translations. For example, converting this equation of a circle to a polar equation: (x+3)^(2)+(y-4)^(2)=4. I have no idea how to do such a thing and cannot find any examples of such.
Hope you can shed some light on this, Thanks.

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f $490 , and he is going to put in $70 per month. Maria opened her account with a starting amount of $670, and she is going to put in $40 per month.
Let x be the number of months after today.
(a)For each account, write an expression for the amount of money in the account after x months.
(b)Write an equation to show that the two accounts have the same amount of money.

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l unemployment rate dropped to about 4%.
Find the average decline/year in unemployment rate from 2010 to 2018.
Let x be the year since 2010 and y be the unemployment rate. Write an equation for unemployment rate versus year.
Use your equation to estimate the unemployment rate in 2020.

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Write a linear equation giving the median salary y in terms of the year X Then use the equation to predict the median salary.

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ned online. Using technology, with x representing the ratings and y representing price, we find that the regression equation has a slope of 130 and a y-intercept of negative 363. Complete parts (a) and (b) below.
a. What is the equation of the regression line? Select the correct choice below and fill in the answer boxes to complete your choice.

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el of the flow in the coating zone x ∈ [0; L], y ∈ [0; h(x)] a lubrication approximation will be developed. If λ >> 1, and if α is close to, but less than 1 the coating zone appears plane. Use the equation of continuity to show by an order of magnitude estimate that |vy| << |vx|. Then state assumptions on flow and pressure field that reduce the Navier- Stokes equation locally to a form, from which the following approximate expression for the x-velocity in the slot for x ∈ [0; L] can be derived:
Se the attached.

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19.2. If the mean of the numbers 9, 10, 11, 12, and x is 12, what is the value ...

s of a sports drink contains 130 milligrams of sodium, what is the total number of milligrams of sodium in 20 ounces of the sports drink?
5. If (k, 3) is a point on the line whose equation is 4x + y = -9, what is the value of k?
9. A flagpole casts a shadow 200 feet long. At the same time, a boy standing nearby who is 5 feet tall casts a shadow 20 feet long. Find the number of feet in the height of the flagpole.
22. What is the greatest value of c for which the roots of the equation x^2 + 4x + c = 0 are real?
24. Find the two acute angles in the right triangle whose sides have the given lengths. Express your answers using degree measure rounded to two decimal places.
7, 24 and 25
A._________________ (smaller value)
B._________________ (larger value)

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20. 1. What is the greatest value of c for which the roots of the equation x^2 + 4x + ...

2. Find the two acute angles in the right triangle whose sides have the given lengths. Express your answers using degree measure rounded to two decimal places.
A._______________________ (Smaller Value)
B. _______________________ (Larger Value)
3. A flagpole casts a shadow 200 feet long. At the same time, a boy standing nearby who is 5 feet tall casts a shadow 20 feet long. Find the number of feet in the height of the flagpole.
4. If (k, 3) is a point on the line whose equation is 4x + y = -9, what is the value of k?
5. If 8 ounces of a sports drink contains 130 milligrams of sodium, what is the total number of milligrams of sodium in 20 ounces of the sports drink?
6. If the mean of the numbers 9, 10, 11, 12, and x is 12, what is the value of x?

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21. Value: 1 equation image indicator a. (x - 2)2(x - 3)2 b. (x2+ 4)(x2+ 9) c. (x - 2)(x + ...

2)(x - 3)(x + 3)
d. (x2 - 4)(x2+ 9)
Value: 1
The table below shows the cost of purchasing a standard stapler at five office supply stores, A through E. If the median cost of purchasing a standard stapler for these stores was $17.99, which of the following could NOT have been the cost of the stapler for Store A?
staplergraph.jpg
a. $19.95
b. $18.95
c. $16.95
d. $19.25
Value: 1
If equation image indicator then x =
a. 7
b. 1/5
c. 5
d. 1/7
Value: 1
A six−sided die, with sides numbered 1,2, 3,4,5, and 6, is tossed. What is the probability of tossing a number less than three?
a. 1/3
b. 0
c. 1/2
d. 1/4
Value: 1
If 6m + 4 = 8m, then 4m =
a. 6
b. 2
c. 8
d. 4
Value: 1
In the xy-plane, what is the y-intercept of the graph of the equation equation image indicator?
a. 2
b. 4
c. 16
d. There is no y-intercept.
Value: 1
Which of the following equations has both 2 and −4 as solutions?
a. x2 + 6x + 8 = 0
b. x2 - 2x - 8 = 0
c. x2 + 2x - 8 = 0
d. x2 - 2x + 8 = 0
Value: 1
The perimeter of a square is 20 ft. If you increase the length of the square by 2 feet and decrease the width by 1 foot, what is the area, in square feet, of the new figure?
a. 22
b. 28
c. 35
d. 40
Value: 1
(3x-2y4)-3 =
a. equation image indicator
b. equation image indicator
c. equation image indicator
d. equation image indicator
Value: 1
A softball is tossed into the air upward from a first floor balcony. The distance of the ball above the ground at any time is given by the function, distance function.png, where h(t) is the height of the softball above the ground (in feet) and t is the time (in seconds). What was the maximum height, in feet, of the softball above the ground after it was thrown?
a. 28
b. 30
c. 32
d. 34
Value: 1
A group of 100 people, some students and some faculty, attended a museum opening. Each student paid $10 per person for entrance to the museum and each of the faculty paid $25 per person for entrance. If the total paid, for all 100 people, was $1300, how many students attended the museum opening?
a. 20
b. 50
c. 70
d. 80
Value: 1
The ratio of Sam's age to Hank's age is 5 to 3. If the sum of their ages is 24, how old is Hank?
a. 21
b. 15
c. 19
d. 9
Value: 1
In the xy−coordinate plane shown below, point P has coordinates (8, −6). Which of the following is an equation of the line that contains points O and P?
O and P graph.jpg
a. equation image indicator
b. equation image indicator
c. equation image indicator
d. equation image indicator
Value: 1
The variables x and y are inversely proportional, and y = 2 when x = 3. What is the value of y when x = 9?
a. 54
b. 6
c. 2/3
d. 3/2
Value: 1
A farmer has 1235 trees to be planted on a rectangular parcel of land. If there are 24 trees planted in each row and each row must be complete before it is planted, how many trees will be left over after planting?
a. 21
b. 11
c. 0
d. 55

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1.AU MAT 120 Systems of Linear Equations and Inequalities Discussion

mathematicsalgebra Physics