Calculate the number of grams of NaCN that must be added to 1.0 L of a 0.5M HCN solution to give a pH of 7.0. (Ka for HCN is 6.2 x 10-10)
A. 0.0034g
B. 11g
C. 24g
D. 160g
E. 0.15g
Answers
The number of grams of NaCN that must be added to the solution is approximately 1.52 x 10^(-8) g.
To calculate the number of grams of NaCN that must be added to 1.0 L of a 0.5M HCN solution to give a pH of 7.0, we need to consider the dissociation of HCN and the resulting concentration of CN- ions.
The dissociation of HCN can be represented by the equation: HCN ⇌ H+ + CN-
Since we want to achieve a pH of 7.0, we know that the concentration of H+ ions should be equal to 10^(-7) M. Using the equation for the dissociation constant (Ka) of HCN (6.2 x 10^(-10)), we can determine the concentration of CN- ions.
Ka = [H+][CN-]/[HCN]
By substituting the known values into the equation, we can solve for [CN-]. Rearranging the equation, we have:
[Cn-] = (Ka * [HCN])/[H+]
[Cn-] = (6.2 x 10^(-10) * 0.5) / 10^(-7)
[Cn-] = 3.1 x 10^(-10) M
Now, we can calculate the number of moles of CN- ions present in the 1.0 L solution:
moles = concentration * volume
moles = 3.1 x 10^(-10) * 1.0
moles = 3.1 x 10^(-10) mol
Finally, we can calculate the mass of NaCN required using the molar mass of NaCN (49.01 g/mol):
mass = moles * molar mass
mass = 3.1 x 10^(-10) * 49.01
mass ≈ 1.52 x 10^(-8) g
Therefore, the number of grams of NaCN that must be added to the solution is approximately 1.52 x 10^(-8) g.
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Related Questions
Predicate logic 1. (x) (Px v Dx) 2. ~Da /Ра 2
1. (∃x)Gx ⊃ (y)(Hy)
2. GC /Hс
Answers
1. The first statement is a universally quantified predicate that states for all x, either Px or Dx is true.
2. The second statement is the negation of Da, which means Da is false. From this, we can infer that Pa is true.
1. The first statement, (∀x)(Px v Dx), expresses that for all x, either Px or Dx is true. This means that every element x satisfies the condition of being either Px or Dx. It does not specify which elements satisfy Px or Dx, but it applies to all x universally.
2. The second statement, ~Da, indicates that Da is false. From the negation of Da, we can infer the truth of its negation, which is Pa. Therefore, we can conclude that Pa is true based on the given information.
By combining the conclusions from the two statements, we can deduce the following:
- (∀x)(Px v Dx) is true for all x.
- ~Da is true, which implies Pa is true.
However, there is no direct relation or implication between Pa and the statement GC / Hc. Without further information or logical connections, we cannot derive the conclusion Hc based solely on the given premises.
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If m = 8, how many solutions are there to the expression 7m?
Answers
Answer:
7m and m = 8
7(8) = 56 one solution and that solution is 56
Step-by-step explanation:
Answer:
Hey there!
There is only one solution.
7(8)=56. It cannot be anything else.
Let me know if this helps :)
Robert got his hair cut for $21. He gave his barber a 15% tip. What was the
TOTAL Robert paid? *
Answers
Answer:
24.15
Step-by-step explanation:
I think
Can someone solve this as soon as possible please
Answers
Answer:
The ratio for this problem is 9 : 100
Step-by-step explanation:
Enjoy
There are 14 boys and 13 girls in a class. Write the ratio of boys
to girls.
Answers
Answer
The answer is 14:13
Simplify the following.
-
1. 3m - 2n + 5m
2. -b - b + 5
3. 50 - 9 - 8C + 5
-
Answers
Answer:
1.\(8m-2n\)
2.\(-2b+5\)
3.\(-8c+46\)
Step-by-step explanation:
Given the following questions:
\(3m-2n+5m\)
\(-b-b+5\)
\(50-9-8c+5\)
To simplify the following we are going to have to regroup and combine like terms which means we are going to use inverse of operations on terms with similar variables.
Question one:
\(3m-2n+5m\)
\(3m-2n+5m=3m+5m-2n\)
\(3m+5m-2n\)
\(3m+5m=8m\)
\(=8m-2n\)
Question two:
\(-b-b+5\)
\(-b-b=-b+-b=-2b\)
\(=-2b+5\)
Question three:
\(50-9-8c+5\)
\(50-9-8c+5=-8c+50-9+5\)
\(-8c+50-9+5\)
\(50-9=41\)
\(-8c+41+5\)
\(41+5=46\)
\(=-8c+46\)
Which means your answers are "8m - 2n, -2b + 5, and -8c + 46."
Hope this helps.
Beatrice makes a jar of dry soup mix. The ingredients are:
1 3/4 cups uncooked rice
1/3 cup beef bouillon
1/2 cup dry lentils
1/4 cup dried onion flakes
1 2/3 = 5/3cups uncooked pasta
1/2 cup dried peas
_______________________
O Commutative Property
O Associative Property
O Zero property
O Distributive property
Answers
i dont know what to do please help
Answers
Answer:
Step-by-step explanation:
Number Price per Total Commission Total cost
of Shares Share (At 6% of total)
100 $16.25 $1625 \(1625\times \frac{6}{100}=97.5\) 1625+97.5 = $1722.5
100 $11.31 $1131 \(1131\times \frac{6}{100}=67.86\) 1131+67.86=$1198.86
40 $9.15 $366 \(366\times \frac{6}{100}=21.96\) 366+21.96=$387.96
100 $15.27 $1527 \(1527\times \frac{6}{100}=91.62\) 1527+91.62=$1618.62
100 $13.22 $1322 \(1322\times \frac{6}{100}=79.32\) 1322+79.32=$1401.32
The diameter of a circle is 2 centimeters. What is the circle's circumference?
Use 3.14 for .
I centimeters
Answers
because C=2pi•r
so in this case C=2•3.14•1
which is C=2•3.14
and that leads to C=6.28cm
hope this helped
Write an expression for the nth term of the sequence. (Your formula should work for n = 1, 2,...) 1/3 middot 4, 2/4 middot 5, 3/5 middot 6, 4/6 middot 7,... Find the first five terms of the given recursively defined sequence. a_n = 3a_n - 1 + 5 and a_1 = 3
Answers
Expression for the nth term of the sequence: (n + 1) / (n + 3).The expression for the nth term of the sequence is (n + 1) / (n + 3). Using this formula, we found the first five terms of the sequence, which are 1/2, 3/5, 4/6, 5/7, and 3/4.
To find the expression for the nth term of the sequence, we observe that each term can be expressed as (n + 1) divided by (n + 3), where n represents the position of the term in the sequence.
Let's verify this formula with the given terms:
For n = 1: (1 + 1) / (1 + 3) = 2 / 4 = 1/2 (first term of the sequence)
For n = 2: (2 + 1) / (2 + 3) = 3 / 5 (second term of the sequence)
For n = 3: (3 + 1) / (3 + 3) = 4 / 6 (third term of the sequence)
For n = 4: (4 + 1) / (4 + 3) = 5 / 7 (fourth term of the sequence)
For n = 5: (5 + 1) / (5 + 3) = 6 / 8 = 3 / 4 (fifth term of the sequence)
Therefore, the first five terms of the given sequence are: 1/2, 3/5, 4/6, 5/7, 3/4.
The expression for the nth term of the sequence is (n + 1) / (n + 3). Using this formula, we found the first five terms of the sequence, which are 1/2, 3/5, 4/6, 5/7, and 3/4.
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｡ﾟﾟ･｡･ﾟﾟ｡
ﾟ。Pain is temporary, swag is forever
ﾟ･｡･ <3
Answers
ASAP!
(1,4) and (6,-1)
Answers
Answer:
-1
Step-by-step explanation:
What is the y-intercept and slope of 3x-5y=15
Answers
Answer:
Slope= 3/5
y-intercept= -3
Step-by-step explanation:
if the probability is f(x) that a product fails the xth time it is being used, that is, on the xth trial, then its FAILURE RATE at the xth trial is the probability that it will fail on the xth trial given that it has not failed on the first x-1 trials; symbolically, it is given by
z(x) = f(x)/(1-F(x-1))
where F(x) is the value of the corresponding distribution function at x. Show that if X is a geometric random variable, its failure rate is constant and equal to p. p is the probability of success.
Answers
X is a geometric random, its variable is constant and equal to p.
How to find geometric random variable?To show that if X is a geometric random variable, its failure rate is constant and equal to p, we will use the definition of the geometric distribution and the failure rate formula.
Recall the probability mass function (PMF) of a geometric random variable X:f(x) = p(1-p)^(x-1), for x = 1, 2, 3, ...Compute the distribution function F(x) for a geometric random variable:
F(x) = P(X ≤ x) = 1 - (1-p)^xPlug f(x) and F(x-1) into the failure rate formula:
z(x) = f(x) / (1 - F(x-1))Substitute the expressions from Step 1 and Step 2:
z(x) = p(1-p)^(x-1) / (1 - (1 - (1-p)^(x-1)))Simplify the expression:
z(x) = p(1-p)^(x-1) / (1-p)^xObserve that (1-p)^x can be written as (1-p)^(x-1) * (1-p):
z(x) = p(1-p)^(x-1) / ((1-p)^(x-1) * (1-p))Cancel out the common terms in the numerator and denominator:
z(x) = p / (1-p)
As the expression for z(x) does not depend on x, the failure rate is constant and equal to p/(1-p). However, we need to show that it is equal to p.
Recall that p is the probability of success. Since failure and success are complementary events, the probability of failure is q = 1-p.
z(x) = p / (1-p) = p / q
Observe that the failure rate z(x) equals the probability of success p when divided by the probability of failure q. Since the failure rate for a geometric random variable only depends on the probability of success p and the probability of failure q, it is constant and equal to p.
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standard form 7.82 x 10-5 answers... 782000/ 78200/ 0.000782/ 0.0000782
Answers
Answer:
Step-by-step explanation:
0.000078 is the answer since you move 5 spaces to the left to get the answer.
Answer:
0.0000782
Step-by-step explanation:
\(7.82 \times {10}^{ - 5} \)You would move the decimal 5 places to the left since it's negative. as you see in the diagram it moves 5 places
A 10m by 7m pond is going to be surrounded with a flower bed of uniform width. The combined area of the pond and flower bed will be 180m^2. Find the width of the flower bed.
Answers
The width of the flower bed is approximately 1.4m.
To solve this problem, we need to use the formula for the area of a rectangle: A = L x W, where A is the area, L is the length, and W is the width.
Let's start by finding the area of the pond:
A pond = 10m x 7m = 70m^2
Next, we need to find the total area of the pond and the flower bed combined. We are given that this area is 180m^2:
A total = A pond + A flower bed
\(180m^2 = 70m^2 + A flower bed\)
\(110m^2 = A flower bed\)
Now we can use the formula for the area of a rectangle again to find the width of the flower bed:
A flower bed = L x W
\(110m^2 = (10m + 2x) (7m + 2x)\)
\(110m^2 = 70m^2 + 20xm + 14xm + 4x^2\)
Simplifying and rearranging, we get:
\(4x^2 + 34xm + 40m^2 - 110m^2 = 0\)
\(4x^2 + 34xm - 70m^2 = 0\)
Dividing both sides by 2, we get:
\(2x^2 + 17xm - 35m^2 = 0\)
Now we can use the quadratic formula to solve for x:
\(x= \frac{-b±\sqrt{(x^{2})-4ac } }{2a}\)
Where a = 2, b = 17m, and \(c = -35m^2\).
Plugging these values in, we get:
\(x =\frac{ (-17m ± \sqrt{17(m)^{2}+280(m)^{2} } }{4}\)
\(x= \frac{(-17m ±\sqrt{697} )}{4}\)
Since the width of the flower bed can't be negative, we take only the positive root:
\(x= \frac{(-17m +\sqrt{697} )}{4}\)
x = 1.4m
Therefore, the width of the flower bed is approximately 1.4m.
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Which is the better buy? (18 points)
7-pack of T-shirts for $23.02
8-pack of T-shirts for $26.72
Answers
Answer: 7 Pack
Step-by-step explanation: Divide each price by the number of shirts :)
what is the slope of a line that is parallel to y=5x 3
Answers
slope is 5
Answer:
solution given:
y=5x-3....[1]
comparing above equation with y=mx+c
we get,
m=5
s0,
slope=5
Step-by-step explanation:
A _____ sample is a sample in which every member of the population has an equal chance of being chosen.
A. systematic
B. probability
C. stratified
D. simple random
Answers
A D. simple random sample is a sample in which every member of the population has an equal chance of being chosen.
A. Systematic: In a systematic sample, the population is first ordered or arranged in some systematic way, such as by alphabetical order or numerical sequence. Then, a starting point is randomly selected, and subsequent members are chosen at regular intervals from the ordered list. This method ensures that every member of the population has an equal chance of being selected.
B. Probability: The term "probability sample" is a general concept that encompasses various sampling methods. It refers to any sample in which each member of the population has a known nonzero probability of being selected. Probability sampling methods include simple random sampling, stratified sampling, cluster sampling, and systematic sampling.
C. Stratified: In stratified sampling, the population is divided into distinct subgroups or strata based on specific characteristics or attributes. Then, a random sample is taken from each stratum in proportion to its representation in the overall population. This method ensures that the sample is representative of the population across different subgroups or strata.
D. Simple random: A simple random sample is a sampling method where each member of the population has an equal and independent chance of being selected. It involves selecting individuals randomly and without any specific pattern or grouping. This method ensures that each member of the population has an equal probability of being chosen, leading to unbiased estimates and generalizability to the larger population.
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Find the total ares of the entire firgure. *
Answers
Answer:
Area of entire fig=Area of rectangle+Area of trianglelet the length be x and breadth be y and h be the height of the triangle
therefore ,
breadth=base
\(x \times y + \frac{1}{2} x \times h\)
ad the values to find the answer
tip:the answer is\( {864in}^{2} \)
Mr. Johnson drove to town at 18mph. Biking at the same route at 12mph, Mr. Smith took 3 hours longer than Mr. Johnson to get to town. How far is the route to town?
Answers
Answer:
To find the distance, we can set up an equation based on the given information. Let's assume the distance to town is represented by "d."
Since Mr. Johnson drove at 18 mph, we can express the time it took for him to reach town as "d/18."
Mr. Smith, on the other hand, biked at 12 mph, and it took him 3 hours longer than Mr. Johnson to reach town. Therefore, we can express the time it took for Mr. Smith as "d/12 + 3."
Setting up an equation, we have:
d/18 = d/12 + 3
To solve for "d," we can multiply both sides of the equation by the least common multiple (LCM) of 18 and 12, which is 36. This gives us:
2d = 3d + 108
Simplifying further, we find:
d = 108
Hence, the distance of the route to town is 108 units.
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I need help with math
Answers
Frank's Hardware's store has a rectangular logo with a width of 3.4m
and area 13 square meters, we are to obtain the length,
\(\begin{gathered} \sin ce\text{ Area=L}\times B \\ The\text{ equation becomes;} \\ L=\frac{13}{3.4} \end{gathered}\)What are 5 ways to study a test?
Answers
Start your schoolwork, Schedule study time Study according to the exam, Defy procrastination, and Study in groups these are the 5 ways to study for a test.
5 ways to study a test can be in the following manner.
1. start your schoolwork
Actually, you should begin preparing for exams and quizzes well before you are aware that a test is coming up. As you take notes in class, you can start developing good study habits. Taking notes helps you to recall what you've read or been taught.
2. Schedule Study Time
Consider how much time you want to spend on each topic before starting to study. By doing this, you'll avoid feeling overloaded.
Determine how much time you will need to study between now and your three tests on Friday if it is Monday and you have three tests on Friday. Then calculate how much time each subject will require
3. Study according to the kind of exam you're taking
A lot of teachers prepare their pupils for exams by explaining the format in advance. You can adjust your study methods as a result. For instance, if you know there will be multiple-choice questions about World War II, you can concentrate on learning facts and specifics. However, if the test will include essay questions, you should consider the subjects that are most likely to be addressed.
4. Defy the urge to put off things.
5. Organize a study group.
Going through the material with others who are preparing for the same test can occasionally be beneficial for ensuring that your notes are accurate and that you comprehend the material. Study groups are beneficial since you may brainstorm strategies to make topics stick in your minds while also testing one another.
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If you are standing 75 ft away from a tree and looking up at the top at a 40° angle, what is the height of the tree?
Answers
Answer:
Step-by-step explanation:
help ima fail if i dont pass thisssssss
Answers
Answer:A
Step-by-step explanation:
George bought a model of a Viking ship for $68. If he paid
$5.10 in sales tax, what was the sales tax rate?
Answers
Answer:
We can convert 6.75% to a decimal by dividing by 100.
If x is the price of the house, then the sales tax is 0.0675x. The price of the house and the sales tax add up to $319,000.
x+0.0675x=319,000
Combe terms on the left.
1.0675x=319,000
Finally, divide both sides by 1.0675.
x=319,0001.0675=298,829.04
Help guys I really need it
Answers
Answer:
yes it does
Step-by-step explanation:
Answer:
yes
Step-by-step explanation:
convertir 26 grados celsius a grados a grados fahrenheit
Answers
Answer:
Para transformar 26 °C a grados Fahrenheit tienes que multiplicar 26 x 9/5 y después sumarle 32. 1 °C son 33,8 °F.
Step-by-step explanation:
26 degrees Celsius is equal to 78.8 degrees Fahrenheit.
To convert 26 degrees Celsius to degrees Fahrenheit, you can use the following formula:
°F = (°C × 9/5) + 32
Plug in the value of celsius.
°F = (26 × 9/5) + 32
°F = (234/5) + 32
°F = 46.8 + 32
°F = 78.8
Therefore, 26 degrees Celsius is equal to 78.8 degrees Fahrenheit.
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Convert 26 degrees Celsius to degrees Fahrenheit?
Whats a difference of a two square (I just need the definition)
Answers
Answer:
In mathematics, the difference of two squares is a squared (multiplied by itself) number subtracted from another squared number. Every difference of squares may be factored according to the identity
{\displaystyle a^{2}-b^{2}=(a+b)(a-b)}a^2-b^2 = (a+b)(a-b)
but you might wanna put it in your own words
you are making two triangular flags for a project and need the flags to be the same shape and size. triangle xyz and triangel x'y'z' are flags you have drawn are the flags the same shape and size explain
Answers
To determine if triangle XYZ and triangle X'Y'Z' are the same shape and size, we need to compare their corresponding angles and side lengths.
Angle Comparison: Check if the corresponding angles in both triangles are equal. If all three angles of triangle XYZ are congruent to the corresponding angles of triangle X'Y'Z', then they have the same shape. However, this does not guarantee they have the same size.
Side Length Comparison: Compare the lengths of the corresponding sides. If all three sides of triangle XYZ are equal in length to the corresponding sides of triangle X'Y'Z', then they have the same size.
If both the angles and side lengths are equal for the corresponding parts of the triangles, then triangle XYZ and triangle X'Y'Z' are congruent, meaning they are the same shape and size.
It's important to note that without specific measurements or additional information about the triangles, it is not possible to definitively determine if they are the same shape and size.
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