Answers
Answer:
B
Step-by-step explanation:
Related Questions
When electricity (the flow of electrons) is passed through a solution, it causes an oxidation-reduction (redox) reaction to occur. If the solution contains a metal cation such as Ag+, the flow of electrons will reduce the silver ion, causing solid silver to plate onto the electrode. The amount of metal plated depends on the number of electrons passed. The total charge of a mole of electrons is 96, 485 coulombs (C) and 1 ampere = 1 coulomb/second (C/s).
What mass of Cu(s) is electroplated by running 28.5 A of current through a Cu2+ (aq) solution for 4.00 h? Express your answer to three significant figures and include the appropriate units.
How many minutes will it take to electroplate 37.1 g of gold by running 5.00 A of current through a solution of Au+(aq)? Express your answer to three significant figures and include the appropriate units.
Answers
Answer:
a. 135 g
b. 60.6 min
Step-by-step explanation:
a. What mass of Cu(s) is electroplated by running 28.5 A of current through a Cu2+ (aq) solution for 4.00 h? Express your answer to three significant figures and include the appropriate units.
The chemical equation for the reaction is given below
Cu²⁺(aq) + 2e⁻ → Cu(s)
We find the number of moles of Cu that are deposited from
nF = It where n = number of moles of electrons, F = Faraday's constant = 96485 C/mol, I = current = 28.5 A and t = time = 4.00 h = 4.00 × 60 min/h × 60 s/min = 14,400 s
So, n = It/F = 28.5 A × 14,400 s/96485 C/mol = 410,400 C/96485 C/mol = 4.254 mol
Since 2 moles of electrons deposits 1 mol of Cu, then 4.254 mol of electrons deposits 4.254 mol × 1 mol of Cu/2 mol = 2.127 mol of Cu
Now, number of moles of Cu = n' = m/M where m = mass of copper and M = molar mass of Cu = 63.546 g/mol
So, m = n'M
= 2.127 mol × 63.546 g/mol
= 135.15 g
≅ 135 g to 3 significant figures
b. How many minutes will it take to electroplate 37.1 g of gold by running 5.00 A of current through a solution of Au+(aq)?
The chemical equation for the reaction is given below
Au⁺(aq) + e⁻ → Au(s)
We need to find the number of moles of Au in 37.1 g
So, number of moles of Au = n = m/M where m = mass of gold = 37.1 g and M = molar mass of Au = 196.97 g/mol
So, n = m/M = 37.1 g/196.97 g/mol = 0.188 mol
Since 1 mol of Au is deposited by 1 moles of electrons, then 0.188 mol of Au deposits 0.188 mol of Au × 1 mol of electrons/1 mol of Au = 0.188 mol of electrons
We find the time it takes to deposit 0.188 mol of electrons that are deposited from
nF = It where n = number of moles of electrons, F = Faraday's constant = 96485 C/mol, I = current = 5.00 A and t = time
So, t = nF/It
= 0.188 mol × 96485 C/mol ÷ 5.00 A
= 18173.30 C/5.00 A
= 3634.66 s
= 3634.66 s × 1min/60 s
= 60.58 min
≅ 60.6 min to 3 significant figures
HELPPPPP WILLLLL AMRK BRAINLIESTTTTTT
Answers
Sade used the two blocks pictured to build a tower. What is the TOTAL VOLUME of the two blocks for this entire tower? *
Answers
Answer: V=120
have an amazing day <3
Answer:what is the answer i dont understand
plz help
If y=1/4x and x=-12, find y.
Answers
Answer:
-3 I believe
Step-by-step explanation:
why dose the answer have to be 20+ letters
Answer:
-3
Step-by-step explanation:
To find y, plug in -12 for x in the y=1/4x equation. Multiply -12 by 1/4 (or divide -12 by 4) and you get -3.
help! geometry
find the arc length of the shaded sector
arc length = blank cm
Answers
Answer:
Step-by-step explanation:
we need the arc length formula . it's Arc length = 2πr (θ/360)
Arc length = 2π5 (144/360)
Arc length = 12.56637 cm
It has been reported that 8.7% of U.S. households do not own a vehicle, with 33.1% owning 1 vehicle, 38.1% owning 2 vehicles, and 20.1% owning 3 or more vehicles. The data for a random sample of 100 households in a resort community are summarized in the frequency distribution below. At the 0.05 level of significance, can we reject the possibility that the vehicle-ownership distribution in this community differs from that of the nation as a whole?
Number of Vehicles Owned Number of Households 0 20 1 35 2 23 3 or more 22 =100
Answers
Answer:
Here, the test statistics ( 20.951 ) is greater than the critical value ( 7.815 )
Therefore, we reject H₀ at 0.05 level of significance.
Hence, there is significant evidence to support the claim that In this community, vehicle ownership distribution is NOT like that of all U.S household
Step-by-step explanation:
Given the data in the question;
Number of vehicle owned Number of households
0 20
1 35
2 23
3 or more 22
Total ( n ) 100
so
Null hypothesis H₀ : In this community, vehicle ownership distribution is like that of all U.S household
Alternative hypothesis Hₐ : In this community, vehicle ownership distribution is NOT like that of all U.S household
Also given that, ∝ = 0.05
Now, we compute the test statistics;
x² = ∑[ ( O[tex]_i[/tex] - E[tex]_i[/tex] ) / E[tex]_i[/tex] ]
where E[tex]_i[/tex] is expected frequency and O[tex]_i[/tex] is observed frequency.
so we make our table for chi square test statistics
No. of O[tex]_i[/tex] P E[tex]_i[/tex] (O[tex]_i[/tex] - E[tex]_i[/tex])² (O[tex]_i[/tex] - E[tex]_i[/tex])²/E[tex]_i[/tex]
Vehicle (n×P)
owned
0 20 0.087 8.7 127.69 14.677
1 35 0.331 33.1 3.61 0.109
2 23 0.381 38.1 228.01 5.985
3 or more 22 0.201 20.1 3.61 0.180
Total 100 100 20.951
hence, x² = 20.951
Now, degree of freedom df = k - 1 = 4 - 1 = 3
From Chi-Square critical value table; ( right tailed test ) for ∝ = 0.05
[tex]x_{0.05, 3[/tex] = 7.815
Decision Rule
Reject H₀ if x² is greater than xₐ².
Here, the test statistics ( 20.951 ) is greater than the critical value ( 7.815 )
Therefore, we reject H₀ at 0.05 level of significance.
Hence, there is significant evidence to support the claim that In this community, vehicle ownership distribution is NOT like that of all U.S household
What is the probability of choosing a 6 of clubs that's also a red card from a deck of cards? Type your answer as a fraction.
Answers
Answer: [tex]\dfrac{1}{52}[/tex]
Step-by-step explanation:
Given
We need to choose 6 of clubs that's also a red
A deck contains 13 cards of clubs, and 6 of clubs is the only red card i.e. favorable outcome is 1 out of 52 cards
Probability is the ratio of favorable to the total outcomes
[tex]\Rightarrow P=\dfrac{1}{52}[/tex]
13.) In 1990, a radio costs $25. Now,
the radio costs $5. What is the
percent of change?
Answers
Answer:
Step-by-step explanation:
80% of 25 = 5
because 10% of 25 = 2.5
and then 10 x 8 = 80
so 2.5 x 8 = 20
25 - 20 = 5
therefore, the percentage change is 80%
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hope this helped,
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write the first five terms of the sequence an=3n^2
Answers
Answer:
2,1,0 is the sequence of its terms
i need help please it's due today
Answers
Step-by-step explanation:
work is on the paper for you, somthing that might help you with your future with math is PEMDAS always do exponents first when it's an equation like your first, second, and third question. I hope this helped.
PLEASE HELP
What is the slope of the line shown below? (Enter your answer as a decimal if
necessary.)
(1, 2)
(-1, -4)
Answers
Answer:
-4-2/-1-1=-6/-2= 3
So the answer is 3
A recent survey reported that small businesses spend 24 hours a week marketing their business. A local chamber of commerce claims that small businesses in their area are not growing because these businesses are spending less than 24 hours a week on marketing. The chamber conducts a survey of 93 small businesses within their state and finds that the average amount of time spent on marketing is 23.0 hours a week. Assuming that the population standard deviation is 5.5 hours, is there sufficient evidence to support the chamber of commerce’s claim at the 0.02 level of significance?
Step 1 of 3 :
State the null and alternative hypotheses for the test. Fill in the blank below.
H0: μ=24
Ha: μ ____ 24
Step 2 of 3:
What is the test statistic?
Step 3 of 3:
Do we reject the null hypothesis? Is there sufficient or insufficient evidence?
Answers
Answer:
Ha: μ < 24
The test statistic is z = -1.75.
The pvalue of the test is 0.0401 > 0.02, which means that we do not reject the null hypothesis, as there is insufficient evidence.
Step-by-step explanation:
A recent survey reported that small businesses spend 24 hours a week marketing their business.
This means that the null hypothesis is:
[tex]H_0: \mu = 24[/tex]
A local chamber of commerce claims that small businesses in their area are not growing because these businesses are spending less than 24 hours a week on marketing.
This means that the alternate hypothesis is:
[tex]H_a: \mu < 24[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
24 is tested at the null hypothesis:
This means that [tex]\mu = 24[/tex]
The chamber conducts a survey of 93 small businesses within their state and finds that the average amount of time spent on marketing is 23.0 hours a week.
This means that [tex]n = 93, X = 23[/tex]
The population standard deviation is 5.5 hours
This means that [tex]\sigma = 5.5[/tex]
Value of the test-statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{23 - 24}{\frac{5.5}{\sqrt{93}}}[/tex]
[tex]z = -1.75[/tex]
The test statistic is z = -1.75.
Do we reject the null hypothesis? Is there sufficient or insufficient evidence?
The pvalue of the test is the probability of finding a sample mean below 23, which is the pvalue of z = -1.75.
Looking at the z table, z = -1.75 has a pvalue of 0.0401
The pvalue of the test is 0.0401 > 0.02, which means that we do not reject the null hypothesis, as there is insufficient evidence.
a. Find three rational numbers between 1/4 and 0.25 repeating
b. Find three rational numbers between 1/3 and 0.34 repeating
Answers
b. 0.3330001, 0.3330002, 0.3330003
By using the definition of rational numbers, we can get:
a) 0.2501, 0.2502, 0.2503b) 0.334, 0.335, 0.336How to find rational numbers?
Remember that a rational number is a number of the form:
N = a/b
Where a and b are integer numbers. Also, any number with a finite number of digits (or infinite repeating) after the decimal point is a rational point.
a) First, we want to find 3 rational numbers between 1/4 and 0.252525...
We can rewrite:
1/4 = 0.25
Then we want to find 3 rationals between 0.25 and 0.2525...
For example, 0.2501 meets this requirement, is larger than 0.25 and smaller than 0.2525...
Another two examples will be 0.2502 and 0.2503
b) Now we have 1/3 = 0.333... and 0.3434...
3 rational numbers between these two are:
0.333... < 0.334 < 0.3434...
0.333... < 0.335 < 0.3434...
0.333... < 0.336 < 0.3434...
If you want to learn more about rational numbers, you can read:
https://brainly.com/question/12088221
Help me with my homework, please
Answers
Answer:
150°
Step-by-step explanation:
We know each angle in a equilateral triangle is 60° and that of a rectangle is 90° . So ,
[tex]\implies \angle ABC = \angle DBC + \angle ABD \\\\\implies \angle ABC = 90^o + 60^o \\\\\implies \boxed{\boxed{ \angle ABC = 150^o }}[/tex]
Estimate 719 – 274. Round each number first.
Answers
719 rounded up equals 720
274 rounded down equals 270
720-270= 450
Suppose y varies directly with x. Write an equation relating x and y.
y = -22.5 when x = 15
a.
b.
y = -0.75x
2
y=-3
c. y=-1.5x
d. y = 1.5x
Answers
point a and point b are placed on a number line point a is located at -20 and point b is 5 less then point a Wich statement about point b is true
Answers
Answer:
Step-by-step explanation:
D beause less then 5 that means it gose down the grid
A rectangular swimming pool is 15 meters long, 11- meters wide, and 4-meters deep. What is its 2 2. volume? The volume is cubic meters.
Answers
Answer:
the volume of the rectangular swimming pool is 660 meters cubic
Step-by-step explanation:
you multiply 15x11x4
Grandma baked 96 cookies and gave them to her grandchildren. One of the grandchildren, Cindy, received
c fewer cookies than she would have received had all of the cookies been evenly divided among the 8
grandchildren.
ining
How many cookies did Cindy receive?
Write your answer as an expression.
Answers
Answer:
12-c
Step-by-step explanation:
This is quite simple
We know grandma has made 96 cookies and IF all children 8 receive equal cookies
They would have 12 cookies each
Cindy got c less cookies
so we can say
12-c is what Cindy got
I guess grandma got hungry
Answer:
Step-by-step explanation:
98 = 8 = 12
cindy cookies = 12-c
he first date went well. You are still dating the same person and still looking for a great person to spend your life with. You are cautiously moving forward with the relationship and know that if they are a great match, their likelihood of being kind to animals is 0.9 whereas their likelihood of being kind to animals if they are not a great match is 0.7. You see that your prospective spouse is kind to animals. What is the probability that they are a great match now?
Answers
Answer:
0.125 = 12.5% probability that they are a great match now.
Step-by-step explanation:
To solve this question, we need the probability of a person being a great match, which i will use 0.1.
This question is solved using conditional probability.
Conditional Probability
We use the conditional probability formula to solve this question. It is
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
In which
P(B|A) is the probability of event B happening, given that A happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Is kind to animals.
Event B: Is a great match.
Probability of being kind to animals:
0.9 of 0.1(Is a great match).
0.7 of 1 - 0.1 = 0.9(is not a great match). So
[tex]P(A) = 0.9*0.1 + 0.7*0.9 = 0.72[/tex]
Probability of being kind to animals and a great match:
0.9 of 0.1. So
[tex]P(A \cap B) = 0.9*0.1 = 0.09[/tex]
What is the probability that they are a great match now?
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.09}{0.72} = 0.125[/tex]
0.125 = 12.5% probability that they are a great match now.
Select the best answer for the question.
7. There are 250 mL of D5W infusing at 33 gtt/
min on IV tubing calibrated at 10 gtt/mL. What is the
infusion time?
O A. 1 hour and 16 minutes
OB. 1.5 hours
O C. 1 hour
O D. 2 hours
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Answers
Answer:
A. 1 hour and 16 minutes
Step-by-step explanation:
There are 250 mL of D5W infusing at 33 gtt/min on IV tubing calibrated at 10 gtt/mL. Calculate the infusion time.
select "No IV pump"
volume = 250 mL
rate = 33 gtt/min
calibration = 10 gtt/mL
Actual formula:
250 /( 33 gtt/min
10x 60)= 1.26 Hours
0.26 x 60 = 16 minutes
So 1.26 Hours = 1 Hour & 16 minutes
hope this will help you
Find the mean, median and mode of the following data sets.
1. 79, 84, 92, 81, 86, 77, 95, 80, 88, 84
2. 8, 9, 9, 9, 9, 10, 11, 15
3. 16, 23, 18, 30, 32, 34, 8, 19, 21
Answers
Answer:
1.
mean= 84.6
median=84
mode=84
2.
mean=10.14
median=9
mode=9
3.
mean=22.3
median=21
mode=phi
Step-by-step explanation:
mean: the sum of of the quantities by their number
median: the median value after rearranging the values
mode: the value that occurs most frequently
in the second question
mean = (8+9+9+9+9+10+11+15)/8
median(even number) =(9+9)/2=9
mode=9
Answer:
for data set 1
1.mean-84.6
2.median-(84+84)/2 = 84
3.mode-84
for data set 2
1.mean-9.25
2.median-(9+9)/2 = 9
3.mode-9
for data set 3
1.mean-22.3
2.median-21
3.mode-no mode with this data set
hope this helped!!
its de in 20 min help me pls and thank you
Answers
Zeros: x = 8, 4
Square: (x - 6)^2 - 4
Vertex: y = (x - 6)^2 - 4
X intercepts: (8,0), (4,0)
Y intercepts: (0, 32)
In triangle ABC, m∠A=(2x)∘, m∠B=(3x+1)∘, and m∠C=(3x−5)∘.
What is the value of x?
Answers
Answer:
x = 23
Step-by-step explanation:
A triangle contains 180°. So, simply create the equation m∠A + m∠B + m∠C = 180° and solve for x.
2x + 3x + 1 + 3x - 5 = 180
8x - 4 = 180
8x = 184
x = 23
The value of x in triangle ABC, where m∠A=(2x)∘, m∠B=(3x+1)∘, and m∠C=(3x−5)∘ is 23.
What is triangle angle sum theorem?According to the triangle angle sum theorem, the sum of all the angle(interior) of a triangle is equal to the 180 degrees.
In triangle ABC,
m∠A=(2x)∘, m∠B=(3x+1)∘, m∠C=(3x−5)∘.As, the sum of all the angles of triangle is equal to the 180 degree. Thus,
[tex]m\angle A+m\angle B +m\angle C=180^o\\(2x)+(3x+1)+(3x-5)=180\\2x+3x+3x=180+5-1\\8x=184\\x=\dfrac{184}{8}\\x=23^o[/tex]
Thus, the value of x in triangle ABC, where m∠A=(2x)∘, m∠B=(3x+1)∘, and m∠C=(3x−5)∘ is 23.
Learn more about the triangle angle sum theorem here;
https://brainly.com/question/7696843
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In a display at a museum, two planets have volumes of 8 cubic inches and 27 cubic
inches. What is the ratio of their diameters?
2:3
413.5
2:9
4:13.5
Answers
Answer:
2:3
Step-by-step explanation:
V = 4/3*pi*r^3
Diameter = 2r
The ratio of diameters of the two planets has volumes of 8 cubic inches and 27 cubic will be 2/3.
What is Ratio?A ratio is defined as a relationship between two quantities, it is expressed as one divided by the other such that they should not be divisible.
The upper number is called as the numerator and the lower is called the denominator.
For example, 3/4 where 3 will be numerator and 4 will be denominator.
Given that the In a display at a museum, two planets have volumes of 8 cubic inches and 27 cubic.
Now volume of planets(sphere) = πD³/6 where D is diameter of sphere
So volume of first planet / volume of second planet ∝ (dia or first)³/(dia of second)³
⇒ V₁/V₂ ∝ (D₁/D₂)³
Given that V₁/V₂ = 8/27
So 8/27 = (D₁/D₂)³
D₁/D₂ = 2/3
Hence, the ratio of diameters of two planets will be 2/3.
Learn more about Ratio here:
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Pls help me pls it’s
Answers
Q) What percentage of sudents who passed the test completed the review sheet
A)
19/27*100
=70.37%
Nearest 10th of a percent
=70%
) Solve
the problem please
Answers
Answer:
0.03703703703
Step-by-step explanation:
Look it up
What linear expression would you add to -4y+2 to have a sum of y
Answers
Answer:
4
Step-by-step explanation:
PLEASE HELP PLEASE
A girls' choir is choosing a uniform for their concert. They can pick red, green or
purple sweaters, and they can pick tan, white or black skirts. The shoes they need
come in gold and black. Assuming all combinations are acceptable, how many
different combinations can the choir pick?
Answers
Answer:
18
Step-by-step explanation:
=============================================================
Explanation:
There are 3 colors to pick for the sweaters (red, green, purple).There are 3 colors for the skirts (tan, white, black)There are 2 colors for the shoes (gold, black)Multiply out those values mentioned to get the final answer: 3*3*2 = 9*2 = 18.
There are 18 different outfit combos.
---------------
Further explanation (optional section):
Let's say we only worried about the sweaters and shoes, and for now there's only one color for the skirt. We have 3 colors for the sweaters and 2 for the shoes. Imagine a table with 3 rows and 2 columns. Each row is a different color for the sweater and each column is a different color for the shoe. There are 3*2 = 6 cells inside the table. Each cell is a different outfit.
For instance, we could have R = red sweater and G = gold shoe. Then that means RG = red sweater + gold shoe outfit. So we'd have RG as one of the cells of this 6 cell table.
Now imagine that we laid out a table that is 6 by 3. The 6 is from the 6 outfits calculated earlier, and the 3 is now accounting for the colors of the skirts. We'd then have 6*3 = 18 combos total. Again, each cell inside the table represents a different outfit combo.
Find the measure of 43.
43
75
43 = [?]
Answers
Answer:
<3=105°
Step-by-step explanation:
The angle directly to the right of the 75° angle is 105°, as the angles along a straight line add to 180.
<3=105° because they are corresponding angles
Answer:
Solution given:
<3+75=180[co- interior angle]
<3=180°-75°=105°
<3=105°
