Answer:
Approximately [tex]4.75[/tex].
Step-by-step explanation:
Remark: this approach make use of the fact that in the original solution, the concentration of [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] are equal.
[tex]{\rm CH_3COOH} \rightleftharpoons {\rm CH_3COO^{-}} + {\rm H^{+}}[/tex]
Since [tex]\rm CH_3COONa[/tex] is a salt soluble in water. Once in water, it would readily ionize to give [tex]\rm CH_3COO^{-}[/tex] and [tex]\rm Na^{+}[/tex] ions.
Assume that the [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] ions in this solution did not disintegrate at all. The solution would contain:
[tex]0.3\; \rm L \times 0.2\; \rm mol \cdot L^{-1} = 0.06\; \rm mol[/tex] of [tex]\rm CH_3COOH[/tex], and
[tex]0.06\; \rm mol[/tex] of [tex]\rm CH_3COO^{-}[/tex] from [tex]0.2\; \rm L \times 0.3\; \rm mol \cdot L^{-1} = 0.06\; \rm mol[/tex] of [tex]\rm CH_3COONa[/tex].
Accordingly, the concentration of [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] would be:
[tex]\begin{aligned} & c({\rm CH_3COOH}) \\ &= \frac{n({\rm CH_3COOH})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}[/tex].
[tex]\begin{aligned} & c({\rm CH_3COO^{-}}) \\ &= \frac{n({\rm CH_3COO^{-}})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}[/tex].
In other words, in this buffer solution, the initial concentration of the weak acid [tex]\rm CH_3COOH[/tex] is the same as that of its conjugate base, [tex]\rm CH_3COO^{-}[/tex].
Hence, once in equilibrium, the [tex]\rm pH[/tex] of this buffer solution would be the same as the [tex]{\rm pK}_{a}[/tex] of [tex]\rm CH_3COOH[/tex].
Calculate the [tex]{\rm pK}_{a}[/tex] of [tex]\rm CH_3COOH[/tex] from its [tex]{\rm K}_{a}[/tex]:
[tex]\begin{aligned} & {\rm pH}(\text{solution}) \\ &= {\rm pK}_{a} \\ &= -\log_{10}({\rm K}_{a}) \\ &= -\log_{10} (1.76 \times 10^{-5}) \\ &\approx 4.75\end{aligned}[/tex].
When A = 200, solve the equation x2 - 40x + A=0 using the quadratic formula. Show all your working and give your answers correct to 2 decimal places.
Answer:
Solution given:
equation is:
x²-40x+A=0
when A=200
equation becomes
x²-40x+200=0
Comparing above equation with ax²+bx+c=0 we get
a=1
b=-40
c=200
By using quadratic equation formulax=[tex]\displaystyle \frac{-b±\sqrt{b²-4ac}}{2a}[/tex]
substituting value
x=[tex]\displaystyle \frac{-*-40±\sqrt{(-40)²-4*1*200}}{2*1}[/tex]
x=[tex]\displaystyle \frac{40±\sqrt{800}}{2}[/tex]
x=[tex]\displaystyle \frac{40±20\sqrt{2}}{2}[/tex]
taking positive
x=[tex]\displaystyle \frac{40+20\sqrt{2}}{2}[/tex]
x=34.14
taking negative
x=[tex]\displaystyle \frac{40-20\sqrt{2}}{2}[/tex]
x=5.86
x=34.14 or 5.86Need the answer please, soon as possible
9514 1404 393
Answer:
(d) 27.4%
Step-by-step explanation:
The desired percentage is ...
(juniors for Kato)/(total juniors) × 100%
= 129/(129 +194 +147) × 100%
= (129/470) × 100% ≈ 27.4%
About 27.4% of juniors voted for Kato.
Which decimal is equivalent to
15/100?
A- O 0.015
B- 0.15
C-o 1.5
D- 0.0015
Answer:
D
Step-by-step explanation:
0.0015
hope this helps
What is the volume of the cylinder below?
Height 4
Radius 7
Answer:
V ≈ 615.75
r Radius 7
h Height 4
If f(x) = x2 + 7x and g(x) = 3x - 1, what is f(g(x))?
Answer:
f(g(x)) = 9x^2 + 15x - 6
Step-by-step explanation:
We are using function g(x) = 3x - 1 as the input to function f(x) = x^2 + 7x.
Starting with f(x) = x^2 + 7x, substitute g(x) for x on the left side and likewise substitute x^2 + 7x for each x on the right side. We obtain:
f(g(x)) = (3x - 1)^2 + 7(3x - 1).
If we multiply this out, we get:
f(g(x)) = 9x^2 - 6x + 1 + 21x - 7, or
f(g(x)) = 9x^2 + 15x - 6
Find:P(large or blue)
Answer:
7/10
Step-by-step explanation:
Total number = 17+3+8+12 = 40
The ones that are large are 17 and 8
The ones that are blue are 17 and 3
Do not count the 17 twice
P(large or blue) = (17+3+8)/40
= 28/40
=7/10
Can someone please help me with this math problem
We have [tex]f\left(f^{-1}(x)\right) = x[/tex] for inverse functions [tex]f(x)[/tex] and [tex]f^{-1}(x)[/tex]. Then if [tex]f(x) = 2x+5[/tex], we have
[tex]f\left(f^{-1}(x)\right) = 2f^{-1}(x) + 5 = x \implies f^{-1}(x) = \dfrac{x-5}2[/tex]
Then
[tex]f^{-1}(8) = \dfrac{8-5}2 = \boxed{\dfrac32}[/tex]
Calls to a customer service center last on average 2.3 minutes with a standard deviation of 2 minutes. An operator in the call center is required to answer 76 calls each day. Assume the call times are independent.
What is the expected total amount of time in minutes the operator will spend on the calls each day?
What is the standard deviation of the total amount of time in minutes the operator will spend on the calls each day? Give your answer to four decimal places.
What is the approximate probability that the total time spent on the calls will be less than 166 minutes? Give your answer to four decimal places. Use the standard deviation as you entered it above to answer this question.
What is the value c such that the approximate probability that the total time spent on the calls each day is less than c is 0.95? Give your answer to four decimal places. Use the standard deviation as you entered it above to answer this question.
Answer:
The expected total amount of time in minutes the operator will spend on the calls each day is of 174.8 minutes.
The standard deviation of the total amount of time in minutes the operator will spend on the calls each day is of 17.4356 minutes.
0.3085 = 30.85% approximate probability that the total time spent on the calls will be less than 166 minutes.
The value c such that the approximate probability that the total time spent on the calls each day is less than c is 0.95 is [tex]c = 203.4816[/tex]
Step-by-step explanation:
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
n instances of a normally distributed variable:
For n instances of a normally distributed variable, the mean is:
[tex]M = n\mu[/tex]
The standard deviation is:
[tex]s = \sigma\sqrt{n}[/tex]
Calls to a customer service center last on average 2.3 minutes with a standard deviation of 2 minutes.
This means that [tex]\mu = 2.3, \sigma = 2[/tex]
An operator in the call center is required to answer 76 calls each day.
This means that [tex]n = 76[/tex]
What is the expected total amount of time in minutes the operator will spend on the calls each day?
[tex]M = n\mu = 76*2.3 = 174.8[/tex]
The expected total amount of time in minutes the operator will spend on the calls each day is of 174.8 minutes.
What is the standard deviation of the total amount of time in minutes the operator will spend on the calls each day?
[tex]s = \sigma\sqrt{n} = 2\sqrt{76} = 17.4356[/tex]
The standard deviation of the total amount of time in minutes the operator will spend on the calls each day is of 17.4356 minutes.
What is the approximate probability that the total time spent on the calls will be less than 166 minutes?
This is the p-value of Z when X = 166.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
For this problem:
[tex]Z = \frac{X - M}{s}[/tex]
[tex]Z = \frac{166 - 174.8}{17.4356}[/tex]
[tex]Z = 0.5[/tex]
[tex]Z = 0.5[/tex] has a p-value of 0.6915.
1 - 0.6915 = 0.3085.
0.3085 = 30.85% approximate probability that the total time spent on the calls will be less than 166 minutes.
What is the value c such that the approximate probability that the total time spent on the calls each day is less than c is 0.95?
This is X = c for which Z has a p-value of 0.95, so X = c when Z = 1.645. Then
[tex]Z = \frac{X - M}{s}[/tex]
[tex]1.645 = \frac{c - 174.8}{17.4356}[/tex]
[tex]c - 174.8 = 1.645*17.4356[/tex]
[tex]c = 203.4816[/tex]
The value c such that the approximate probability that the total time spent on the calls each day is less than c is 0.95 is [tex]c = 203.4816[/tex]
..............................
Answer:
[tex]x=17[/tex]
Step-by-step explanation:
[tex](6x+10)(x+17)(4x-34)[/tex]
[tex]6x+10+x+17+4x-34=180[/tex]
Add:- [tex]6x+x+4x=11x[/tex]
and [tex]10+17-34=-7[/tex]
So, [tex]11x-7=180[/tex]
Add 7 to both sides:-
[tex]11x=187[/tex]
Divide both sides by 11:-
[tex]\frac{11x}{11}=\frac{187}{11}[/tex]
[tex]x=17[/tex]
OAmalOHopeO
which is an example of an algebraic expression
A.4(3+8)
B.18^2
C. 3-a
D. 12•4
Answer:
C: 3-a
Step-by-step explanation:
The answer is C because an algebraic expression needs to have a variable in it. The variable is "a," so the answer has to be C.
Answer:
Option C : as in algebraic expression there must a variable and constant.
How to find Joint and Combined variation?
Answer:
W is multiplied by 8
Step-by-step explanation:
If W varies jointly with x, y, and z, we can say that
W = k (xyz), with k being a constant for our original equation. We are asked what will happen to W if x, y, and z are each doubled. To figure this out, we can go back to our equation,
W = k (xyz)
First, we can double x, meaning that we multiply it by 2. Doing this, we get
W = k (2x * y * z)
Then, we can double y and z in a similar fashion, resulting in
W = k (2x * 2y * 2z)
W = 8 * k (xyz)
The new W, after all the doubling, is equal to 8 * k * x * y * z. The old W is equal to k * x * y * z. It can be determined that the new W is equal to 8 * the old W, so W is multiplied by 8
Casey's phone service charges a flat monthly fee of $30 for the first 1000 minutes of calls and $0.40 per minute over 1000. Determine Casey's monthly charge if he makes 1,100 minutes of calls?
Answer:
Casey's monthly charge for making 1,100 minutes of calls is $70.
Step-by-step explanation:
We can write a piecewise function to model the situation.
Since Casey's phone service only charges a monthly fee of $30 for the first 1000 minutes, we can write that for calling t minutes:
[tex]\displaystyle C(t) = 30\text{ if } t\leq 1000[/tex]
In other words, the total cost is only $30 is the total minutes of call is less than 1000 minutes.
However, if the total minutes of calls is greater than 1000, then its $0.40 per minute on top of the 30. Thus:
[tex]\displaystyle C(t) = 30 + 0.4(t-1000)\text{ if } t>1000[/tex]
All together, our piecewise function will be:
[tex]\displaystyle C(t) = \begin{cases} 30 & t\leq 1000 \\ 30 + 0.4(t-1000) & t>1000\end{cases}[/tex]
We want to determine Caseys monthly charge if he makes 1,100 minutes of calls. So, t = 1100. Since 1100 > 1000, we will use the second equation. This yields:
[tex]C(1100)= 30+0.4((1100)-1000)[/tex]
Evaluate:
[tex]\displaystyle C(1100) = 30+0.4(100) = 30+40=\$70[/tex]
Casey's monthly charge for using 1,100 minutes of call is $70.
Which expression is the radical form of 1/5b
Answer:
1st option, ⁵√b
Step-by-step explanation:
b⅕
= ⁵√b (radical form)
express 111 as a sum of two primes
Answer:
2 + 109 = 111
Step-by-step explanation:
.............
Write the polynomial in standard form. Then name the polynomial based on its degree and number of
terms.
y-7y3 + 15y9
Answer:
[tex]15y^9 - 7y^3 + y[/tex]
Nonic polynomial
Step-by-step explanation:
Given
[tex]y - 7y^3 + 15y^9[/tex]
Required
Write in standard form
The standard form of a polynomial is:
[tex]ay^n + by^{n-1} + ......... + k[/tex]
So, we have:
[tex]y - 7y^3 + 15y^9[/tex]
The standard form is:
[tex]15y^9 - 7y^3 + y[/tex]
And the name is: Nonic polynomial (because it has a degree of 9)
Find the measure of the missing angles.
Answer:
b = 53
c = 53
Step-by-step explanation:
Alright so we already know that b and c are going to have the same angle measures. We can find b by subtracting 180 degrees to 127. Why you may ask? Its because when b and 127 are added together its obvious that it creates a straight line (supplementary angle). This means that two angles will sum up to 180 degrees. We can create an easy equation and solve for b.
127 + b = 180
b = 53 and c = 53
Best of Luck!
Kế hoạch đi dã ngoại của một gia đình sẽ bị hủy nếu trời có mây hoặc mưa. Biết xác suất để trời có mây là có mưa là có cả mây và mưa là . Tính xác suất để kế hoạch được thực hiện.
Answer:
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Raul is a manager at a local restaurant. He earns $18.50 per hour. How many hours per week does Raul
work if he earns $740 per week?
What is the equation of the line through (4, -3) and (0, -2)?
O A. y = -x + 2
B. Y= -1x – 2
O C. y= - 4x –
D. y = 4x + 2
Answer:
B
Step-by-step explanation:
Pull in -4 and 0 into the variable x. and the 4 and -2 in the variable y and solve to get an equal answer.
Chad has a win loss ratio 5:5 across his games what percentage of games did he win
Answer:
Step-by-step explanation:
50%
Answer:
50%
Step-by-step explanation:
Win % = wins / total * 100%
Win% = (5/(5 + 5)) * 100
Win% = 5/10 * 100 = 50%
I need to know the answer and explaining how to do it please
Answer:
Its 0.11
Step-by-step explanation:
When you divide any number by 10, you just move the decimal place one to the left, as for this number 1.1, you move it one place to the left which makes it 0.11. Mathmatically, to check your work you can do 0.11 x 10 to get 1.1
Mark brainliest and helpful
relationship between the two number
b 70.908
7.908
Which one is greater
Answer:
70.908 is greater than 7.908 .
I hope your day goes nice
Answer:
70.9 0 8 is Greaterboth are different because of different placement of point.
What is the correct answer?
Answer:
Option D
Only the equation in option D matches with the table
Answered by GAUTHMATH
The firm had 15 billion VND of earnings before interest and tax (EBIT), corporate tax is 20%. The market price of stock is 60.000đ. Knowing that net income will be held 40% before using it for dividend. How much of the net income can be divided for shareholders?
Answer:
was assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
1. In the game of baseball, which is rather boring, the batter stands on home base (Hughes 1).
2. Baseball is rather surprisingly known as "America's Favorite Pastime."
3. Baseball is "a rather boring sport played between two teams of nine players" (Hughes 1).
4. All of these are plagiarism.
The answer tells that only the third choice is NOT a plagiarism. My question is, why is the first choice a plagiarismwas assigned with this problem (the reference text is attached):
Which of the following, if included in a student's paper, would NOT be an example of plagiarism?
A state lottery sells instant-lottery scratch tickets. 12% of the tickets have prizes. Neil goes to the store and buys 10 tickets. What is the probability that exactly three of Neil's tickets will have prizes?
Answer:
The probability of success is .12
The probability of failure is .88
According to the binomial theorem the probability of 3 success is
10! / (3! * 7!) * .12^3 * .88^7 = .085
find the exact value of tan(165°) using a difference of two angles
Answer: [tex]-2+\sqrt{3}[/tex]
=========================================================
Work Shown:
Apply the following trig identity
[tex]\tan(A - B) = \frac{\tan(A)-\tan(B)}{1+\tan(A)*\tan(B)}\\\\\tan(225 - 60) = \frac{\tan(225)-\tan(60)}{1+\tan(225)*\tan(60)}\\\\\tan(165) = \frac{1-\sqrt{3}}{1+1*\sqrt{3}}\\\\\tan(165) = \frac{1-\sqrt{3}}{1+\sqrt{3}}\\\\[/tex]
Now let's rationalize the denominator
[tex]\tan(165) = \frac{1-\sqrt{3}}{1+\sqrt{3}}\\\\\tan(165) = \frac{(1-\sqrt{3})(1-\sqrt{3})}{(1+\sqrt{3})(1-\sqrt{3})}\\\\\tan(165) = \frac{(1-\sqrt{3})^2}{(1)^2-(\sqrt{3})^2}\\\\\tan(165) = \frac{(1)^2-2*1*\sqrt{3}+(\sqrt{3})^2}{(1)^2-(\sqrt{3})^2}\\\\\tan(165) = \frac{1-2\sqrt{3}+3}{1-3}\\\\\tan(165) = \frac{4-2\sqrt{3}}{-2}\\\\\tan(165) = -2+\sqrt{3}\\\\[/tex]
----------------------
As confirmation, you can use the idea that if x = y, then x-y = 0. We'll have x = tan(165) and y = -2+sqrt(3). When computing x-y, your calculator should get fairly close to 0, if not get 0 itself.
Or you can note how
[tex]\tan(165) \approx -0.267949\\\\-2+\sqrt{3} \approx -0.267949[/tex]
which helps us see that they are the same thing.
Further confirmation comes from WolframAlpha (see attached image). They decided to write the answer as [tex]\sqrt{3}-2[/tex] but it's the same as above.
The height of an object dropped from the top of a 144-foot building is given by ℎ(. How long will it take the object to hit the ground?)=―162+144
Answer:
Step-by-step explanation: h(t) = -16t2 + 144
h(1) = -16(12) + 144 = 128 ft
h(2) = -16(22) + 144 = 80 ft
h(2) - h(1) = 80 - 128 = -48 ft
It fell 48 ft between t = 1 and t = 2 seconds.
It reaches the ground when h(t) = 0
0 = -16t2 + 144
t = √(144/16) s = 3s
It reaches the ground 3s after being dropped.
2 men can build a wall in 10 days. in how many days will 8 men build the wall?
Step-by-step explanation:
8 men can do 60 man days of work by dividing 60 man days by the 8 men, which gives us 60/8 = 7 1/2 da
find the area of the circle use 3.14 for pi d=4 m
Answer:
The area of circle is 12.56m sq.
rewrite the following statements into algebraic expression
the sum of x and y
5 is subtracted from y
