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
Harold can solve 25 math problems in 40 minutes. At that rate, how many minutes will it take Harold to solve 60 math problems?
Find the volume of the pyramid.
Please Help!
Answer:
144cm
Step-by-step explanation:
Just search it up lol
For what value of z would the following system of
equations be true for all real integers?
3x-2y = 14
-12x+8y = 8z
9514 1404 393
Answer:
z = -7
Step-by-step explanation:
The equations will be true for all real integers when they are a dependent set. That will be the case when the second equation is a multiple of the first.
Already, we observe that the ratios of x- and y-coefficients are -4:
-12/3 = -4
8/-2 = -4
The equations will be dependent when the constants have that same ratio:
8z/14 = -4 . . . . desired ratio
8z = -56 . . . . . multiply by 14
z = -7 . . . . makes the equations true for all real numbers
_____
Comment on the question
The system of equations can be made inconsistent (no solutions) or consistent & dependent (infinite solutions) by the choice of z.
However, integer solutions are limited to pairs of the form (2n+2, 3n-4) for integer values of n. The values of x and y are not "all real integers".
Consequently, we have interpreted the question to be asking for the value of z that will make the system of equations have an infinite number of solutions, including both rational and irrational, real and complex values of x and y. They cannot be made to be true for "all real integers" by any choice of z.
Answer:
z = -7 is the answer.Step-by-step explanation:
#CarryOnLearningApproximate, in square meters, the area of a circle with radius = 58.2 m. (Round your answer to three decimal places.)
Answer:
10,635.934 m^2
Step-by-step explanation:
The formula for area of a circle is π r² (pi ⋅ radius ⋅ radius)
According to the word problem, 58.2 is the radius.
Now that we know the radius, we have our final equation:
pi ⋅ radius ⋅ radius
(3.14 IS USED FOR PI)
3.14 ⋅ 58.2 ⋅ 58.2 = 10,635.9336
10,635.9336 rounded to the three decimal places (to the nearest thousandth): 10,635.934
Therefore, the area of this circle in square meters is 10,635.934 m^2.
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?
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.
In triangle ABC, m∠A=(2x)∘, m∠B=(3x+1)∘, and m∠C=(3x−5)∘.
What is the value of x?
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;
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Solution set no links please
I believe that the answer is 11/4. I hope this helps!
What’s 22,000 - 407% of 60?
Answer:
21,755.8
Step-by-step explanation:
To solve this equation, we must first find 407% of 60.
To do this, place the percent over 100 (fraction form), then, multiply it by the number you're finding the percentage of.
407/100 x 60/1 = 24,420/100
24420 / 100 = 244.2
244.2 is 407% of 60.
Lastly, you subtract 244.2 from 22,000.
22,000 - 244.2 = 21,755.8
Answer:
21755.8
Step-by-step explanation:
407%=4.07
4.07*60=244.2
22,000-244.2=21755.8
WILL MARK BRAINLIEST IF FOTTEN RIGHT!!!
Answer:
A
Step-by-step explanation:
area = [tex]\pi r^{2}[/tex]
circumference = [tex]2\pi r[/tex]
[tex]r^{2} = 4\\\sqrt{r^{2}} =\sqrt{4} \\r = 2[/tex]
[tex]2\pi (2) = 4\pi[/tex] [tex]yd[/tex]
Sade used the two blocks pictured to build a tower. What is the TOTAL VOLUME of the two blocks for this entire tower? *
Answer: V=120
have an amazing day <3
Answer:what is the answer i dont understand
plz help
If the given figure is rotated 180° around the origin, what are the new coordinates of point Z?
please I really need help with this.
Answer:
New coordinates of the point Z are (-6, 9)
Step-by-step explanation:
If a point (x, y) is rotated 180° about the origin, coordinates of the image point is given by the rule,
(x, y) → (-x, -y)
Coordinates of the vertex Z → (6, -9)
Following the same rule,
Z(6, -9) → Z'(-6, 9)
Therefore, coordinates of the new (image) point will be (-6, 9).
The lengths of a certain species of beetles are normally distributed with a mean of 1.9 centimeters and a standard deviation of 0.2 centimeters.
What is the z-score of a beetle of this species with a length of 2.38 centimeters?
Enter your answer in the box.
Enter your answer, rounded to the nearest tenth, in the box.
Answer:
The z-score of a beetle with a length of 2.38 centimeters is 2.4
Step-by-step explanation:
As we know,
z = (x - µ)/σ
x is the length of the beetle species.
µ is the mean length
σ is the standard deviation
Substituting the given values in above equation, we get
z = (2.38 - 1.9)/0.2
z = 0.48/0.2
z = 2.4
help with this math assignment
If a triangle has a center of dilation at the origin and a scale factor of two. if point he was at(-2,-3) what would point A’ would be.
Answer: Second option.
Step-by-step explanation:
First it is important to remember the definition of Dilation.
A Dilation is defined as a transformation in which the Image (The figure obtained after the transformation) and the Pre-Image (The original figure, before the transformation) have the same shape, but their sizes are different.
In this case you know that the triangle ABC is dilated by a scale factor of 2 with a center of dilation at the origin.
According to the exercise, the point C has these coordinates:
Therefore, in order to find the coordinates of C', you need to multiiply the coordinates of the point C by the scale factor 2.
Then, you get that the coordinates of the point C' are:
Estimate 719 – 274. Round each number first.
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.
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
What is the area of a rectangle with 4 1/3 length and 2 1/2 width?
MAX POINTS PLEASE HELp
part a. What are the values of x and y? If your answer is not a whole number, write it as a decimal and round to one decimal place if necessary.
part b:
Here is a triangular prism.
What is the volume of the prism, in cubic centimeters?
cubic centimeters
What is the surface area of the prism, in square centimeters?
cubic centimeters
Answer:
X=35 Y=73
Step-by-step explanation:
use the opposite angle theorem for x. X would equal 35.
we know that x is 35. So 2y+35=180
180-35=2y
y=72.5 or 73
srry I can’t help with question 2. I don’t know how
The height of a cone is two times its base diameter. What is the volume of the cone in terms of its base radius ?
Step-by-step explanation:
Cone Volume = 1/3 ×( π r² h) h = 2 × diameter = 2 × 2 × r
Cone Volume = 1/3 ×( π r² h) h = 2 × diameter diameter = 2r
= 2 × (2 × r)
= 4r
Cone Volume = 1/3 ×( π r² 4r)
= (4 π r³ / 3)
PLEASE HELP!
In the figure below, m∠R is 66°, and m∠T is 122°.
Note: Figure is not drawn to scale.
What is m∠Q?
A.
58°
B.
56°
C.
24°
D.
124°
Answer:
B. 56°
Step-by-step explanation:
We are given that m∠R is 66° and m∠T is 122°.
We can apply the supplementary rule since ∠S and ∠T are a linear pair. So, we can use ∠T to find ∠S through 180° - 122° = 58°.
Now, we can use ∠R and ∠S to find ∠Q.
66° + 58° = 124°
180° - 124° = 56°
Answer:
m∠Q is 56°.
Step-by-step explanation:
An exterior angle of a triangle is equal to the sum of the two interior angles that are not adjacent to that exterior angle.
In this case, ∠T is an exterior angle of the triangle, and ∠Q and ∠R are the two interior angles that are not adjacent to ∠T.
So, the measure of ∠T is equal to the sum of the measure of ∠Q and the measure of ∠R.
Therefore, m∠Q is 56°.
A large school district claims that 80% of the children are from low-income families. 150 children from the district are chosen to participate in a community project. Of the 150 only 70% are from low-income families. The children were supposed to be randomly selected. Do you think they really were
Incomplete question. However, I answered from a general research perspective.
Explanation:
Note, the term sample used in statistical research refers to subjects or persons carefully selected (using a particular sampling method/type ) to represent the target population.
A randomly selected sample could be done as either:
Simple Random Sampling Stratified Random Sampling Cluster Random Sampling.Systematic Random Sampling.Using any of the above sampling methods could result in 70% of the population being from low-income families as this is a matter of chance. Hence, we can agree with the research results.
Using the z-distribution, it is found that since the test statistic is less than the critical value for the left-tailed test, there is enough evidence to conclude that the children were not randomly selected.
At the null hypothesis, we test if they were really randomly selected, that is, the proportion is of 80%:
[tex]H_0: p = 0.8[/tex]
At the alternative hypothesis, we test if they were not randomly selected, that is, the proportion is of less than 80%.
[tex]H_1: p < 0.8[/tex]
The test statistic is given by:
[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]
In which:
[tex]\overline{p}[/tex] is the sample proportion. p is the proportion tested at the null hypothesis. n is the sample size.For this problem, the parameters are:
[tex]p = 0.8, n = 150, \overline{p} = 0.7[/tex]
Then, the value of the test statistic is:
[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]
[tex]z = \frac{0.7 - 0.8}{\sqrt{\frac{0.8(0.2)}{150}}}[/tex]
[tex]z = -3.06[/tex]
The critical value for a left-tailed test, as we are testing if the proportion is less than a value, with a significance level of 0.05, is of [tex]z^{\ast} = -1.645[/tex].
Since the test statistic is less than the critical value for the left-tailed test, there is enough evidence to conclude that the children were not randomly selected.
A similar problem is given at https://brainly.com/question/24166849
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
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
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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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
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.
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]
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
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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⚠️PLEASEEEEE HELPPPPPP !!!
Answer:
38
Step-by-step explanation:
I'm pretty sure its just the same
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.
Answer:
the volume of the rectangular swimming pool is 660 meters cubic
Step-by-step explanation:
you multiply 15x11x4
what is the value of the expression below? (64^3)^1/6
Answer:
(64^3)^(1/6)
=(64)^(3×1/6)
=(64)^(1/2)
=(8^2)^(1/2)
=(8)^(2×1/2)
=8^1
=8
8 is the correct answer of your question...
Answer:
8
Step-by-step explanation:
Remember the phrase "power to a power means to multiply the exponents"
That is, if you have a number (call it x) raised to a power (call it b), and that whole expression is raised to a power (call it c), it's the same as that number x raised to the power of the product of those two powers.
[tex](x^a)^b = x^a^b[/tex]
Here's an example showing to give some intuition behind this (and a way to derive the above formula if you forget it):
[tex]x^3 = x*x*x\\(x^3)^2 = (x*x*x)^2 = x*x*x*x*x*x = x^6[/tex]
Or more simply,
[tex](x^3)^2 = x^(^3^*^2^) = x^6[/tex]
So in this case:
[tex](64^3)^\frac{1}{6} = 64^(^3^*^\frac{1}{6}^) = 64^\frac{1}{2} = 8[/tex] (remember a number raised the to the power of 1/2 is the square root of the number; in this case, the square root of 64 is 8)
a. Find three rational numbers between 1/4 and 0.25 repeating
b. Find three rational numbers between 1/3 and 0.34 repeating
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:
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ABCD is a square and it's side is 16 cm long. What is the area of the shaded part?
Answer:
I'm sorry I can't help because I don't know what part is shaded. Note: Since a square has the same length for each side all the sides are 16 cm.
Area and Perimeter for WHOLE square:
A: 256 sq cm
P: 64 cm