Answer: Atomic mass (Cu) = (x)(63.0 amu) + (1 – x)(65.0 amu) = 63.5 amu 63.0x + 65 – 65.0x = 63.5 –2x = –1.5 x = 0.75 The percent abundance of each isotope is 75.0 % (Cu-63) and 25.0 % (Cu-65).
Explanation: As you know, the average atomic mass of an element is determined by taking the weighted average of the atomic masses of its naturally occurring isotopes.
Simply put, an element's naturally occurring isotopes will contribute to the average atomic mass of the element proportionally to their abundance.
What is the entropy of this collection of training examples with respect to the positive class B. What are the information gains of A1 and A2 relative to the training dataset For A3, which is a continuous attribute, compute the information gain for every possible split. C. What is the best split (among A1,A2, and A3) according to the information gain
The data set is missing in the question. The data set is given in the attachment.
Solution :
a). In the table, there are four positive examples and give number of negative examples.
Therefore,
[tex]$P(+) = \frac{4}{9}$[/tex] and
[tex]$P(-) = \frac{5}{9}$[/tex]
The entropy of the training examples is given by :
[tex]$ -\frac{4}{9}\log_2\left(\frac{4}{9}\right)-\frac{5}{9}\log_2\left(\frac{5}{9}\right)$[/tex]
= 0.9911
b). For the attribute all the associating increments and the probability are :
[tex]$a_1$[/tex] + -
T 3 1
F 1 4
Th entropy for [tex]$a_1$[/tex] is given by :
[tex]$\frac{4}{9}[ -\frac{3}{4}\log\left(\frac{3}{4}\right)-\frac{1}{4}\log\left(\frac{1}{4}\right)]+\frac{5}{9}[ -\frac{1}{5}\log\left(\frac{1}{5}\right)-\frac{4}{5}\log\left(\frac{4}{5}\right)]$[/tex]
= 0.7616
Therefore, the information gain for [tex]$a_1$[/tex] is
0.9911 - 0.7616 = 0.2294
Similarly for the attribute [tex]$a_2$[/tex] the associating counts and the probabilities are :
[tex]$a_2$[/tex] + -
T 2 3
F 2 2
Th entropy for [tex]$a_2$[/tex] is given by :
[tex]$\frac{5}{9}[ -\frac{2}{5}\log\left(\frac{2}{5}\right)-\frac{3}{5}\log\left(\frac{3}{5}\right)]+\frac{4}{9}[ -\frac{2}{4}\log\left(\frac{2}{4}\right)-\frac{2}{4}\log\left(\frac{2}{4}\right)]$[/tex]
= 0.9839
Therefore, the information gain for [tex]$a_2$[/tex] is
0.9911 - 0.9839 = 0.0072
[tex]$a_3$[/tex] Class label split point entropy Info gain
1.0 + 2.0 0.8484 0.1427
3.0 - 3.5 0.9885 0.0026
4.0 + 4.5 0.9183 0.0728
5.0 -
5.0 - 5.5 0.9839 0.0072
6.0 + 6.5 0.9728 0.0183
7.0 +
7.0 - 7.5 0.8889 0.1022
The best split for [tex]$a_3$[/tex] observed at split point which is equal to 2.
c). From the table mention in part (b) of the information gain, we can say that [tex]$a_1$[/tex] produces the best split.
What would you call the bright blue liquid?
The speed of an electron is 1.68*10^8m/s what is the wavelength
Answer:
[tex]\lambda =4.33x10^{-12}m=4.33pm[/tex]
Explanation:
Hello there!
In this case, since the speed, wavelength and mass of an electron are related via the the Broglie wavelength:
[tex]\lambda =\frac{h}{m*v}[/tex]
Thus, by plugging in the mass of the electron and the Planck's constant, we obtain the following wavelength:
[tex]\lambda =\frac{6.626x10^{-34}J*s}{9.11x10^{-31}kg*1.68x10^{8}m/s}\\\\\lambda =4.33x10^{-12}m=4.33pm[/tex]
Best regards!
The reason for using 1-propanol as the solvent of choice for recrystallization is that triphenylphosphine oxide is more soluble in 1-propanol than the alkene product because triphenylphosphine oxide can use its oxygen to hydrogen-bond to 1-propanol, whereas the alkene has no hydrogen-bonding capability. Triphenylphosphine oxide, therefore, is removed based on its polarity and H-bonding ability.
a. True
b. False
Answer:
True
Explanation:
Hydrogen bonding is a bond that exists between hydrogen and a highly electronegative element such as oxygen, nitrogen, fluorine etc.
The greater solubility of the triphenylphosphine oxide owes to the hydrogen bonded interaction between it and the 1-propanol.
The alkene lacks such hydrogen bonded interaction because it does not have a highly electronegative atom in its structure.
Hence, triphenylphosphine oxide is removed based on its polarity and hydrogen bonding ability.
Characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices. (1) Water's boiling point is much higher than expected, based on comparison with other substances, because of hydrogen bonding. (2) In the gaseous state, disruptive forces and cohesive forces are of about the same magnitude. (3) As liquid surface area increases, the rate of evaporation of a liquid increases.
Answer:
The correct answer is - 1 and 3 are true.
Explanation:
Hydrogen bonds require a lot of energy to be broken as these bonds are relatively strong intermolecular forces which makes the boiling point of liquid like water very high, as it requires a lot of heat to break the intermolecular bonds holding the water molecules together.
An increase in the surface area of the liquid also increases the rate of evaporation as it takes place among the molecules of the liquid on the surface.
What do the symbols in the parentheses indicate
Answer:
(C) the physical state of each reactant and product
Explanation:
Hope this helps
From these four cycles which are water cycle, carbon cycle, nitrogen cycle, and phosphorus cycle which cycle has more nutrients
Answer:
Nitrogen cycle
Explanation:
Use the periodic table to answer this question.
How many moles of He are in 16 g of the element?
A 4.0 mol
B 1.0 mol
C 8.0 mol
D 16 mol
Answer:
A. 4.0 mol
Explanation:
Divide 16 g by the molar mass of He, which is 4.0 g/mol.
16 g / 4.0 g/mol = 4.0 mol
arrange the following group of atoms in order of increasing atomic size:B,Al,Ga
Answer:
Al,Ga,B
Explanation:
Now since i helped you can you help me with this plz
Matteo took 5 math quizzes. The mean of the 5 quizzes was 8.2. Here are four of his quiz scores 7, 7, 8, 10. What is the 5th quiz score? Show work.
Boron ( B )
Aluminium ( Al )
Gallium ( Ga )
The Earth's asthenosphere is a structural layer
A.
that is made of the crust and the uppermost part of the mantle.
B.
that is contained completely within the crust.
C.
that is contained completely within the upper mantle.
D.
that is made of the mantle and the uppermost part of the crust.
Answer:
Dont completly trust me here but i think its a but id try and wait for someone else just be careful
Explanation:
A gas occupies a volume of 2.4 L at 0.14 ATM. What volume will the gas occupy at 0.84 ATM?
Answer:
0.4 L
Explanation:
Calculate by using Boyle's Law P₁V₁=P₂V₂
(0.14atm)(2.4L) = (0.84atm)(V₂)
0.336 atmL = (0.84atm)(V₂)
V₂ = 0.336 atmL/0.84atm
V₂ = 0.4 L
If 50.0 g of silicon dioxide is heated with an excess of carbon, 27.9 g of silicon carbide is produced. What is the percent yield of the reaction
Answer: The percent yield of the reaction is 83.5 %
Explanation:
The given balanced equation is
[tex]SiO_2+3C\rightarrow SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and [tex]C[/tex] is the excess reagent.
According to stoichiometry :
60.08 g of [tex]SiO_2[/tex] produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce=[tex]\frac{40.11}{60.08}\times 50.0=33.4[/tex] of [tex]SiC[/tex]
Experimental yield of SiC = 27.9 g
Percent yield = [tex]\frac{\text {Experimental yield}}{\text {theoretical yield}}\times 100=\frac{27.9g}{33.4g}\times 100=83.5\%[/tex]
Thus percent yield of the reaction is 83.5 %
The percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
What is the chemical balance of the equation?
The chemical equations are balanced when the reactants react to form products. The reactants and products react in proper ratios and if they are not in ratio then we balance them by adding the required quantity in the reactants and the products.
The given balanced equation is
[tex]\rm SiO_2+3C---- > SiC+2CO[/tex]
[tex]SiO_2[/tex] is the limiting reagent as it limits the formation of product and is the excess reagent.
According to stoichiometry
60.08 g [tex]SiO_2[/tex] of produce = 40.11 of [tex]SiC[/tex]
Thus 50.0 of [tex]SiO_2[/tex] will produce= [tex]\dfrac{40.11}{60.08} \times 50=33.4\ SiC[/tex]
The experimental yield of SiC = 27.9 g
The percentage yield will be calculated as
[tex]\rm Percentage \ Yield = \frac{Experimental\ yield}{Theoretical \ yield }\times 100[/tex]
[tex]\rm Percentage \ yield =\dfrac{27.9}{33.49} \times 100=83.5[/tex]
Thus the percent yield of 83.5 % of 50.0 g of silicon dioxide is heated with an excess of carbon, and 27.9 g of silicon carbide is produced in the reaction.
To know more about balanced chemical equations follow
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Choose the options below that are true.
A. The rate law for a given reaction can be determined from a knowledge of the rate-determining step in that reaction's mechanism.
B. The rate laws of all chemical reactions can be determined directly from their net chemical equations.
C. The rate laws of bimolecular elementary reactions are second order overall.
D. The rate law for a given reaction can be determined from its reaction mechanism, without the accompanying rates of each elementary step in the mechanism.
Answer:
The options (A) -The rate law for a given reaction can be determined from a knowledge of the rate-determining step in that reaction's mechanism. and (C) -The rate laws of bimolecular elementary reactions are second order overall ,is true.
Explanation:
(A) -The rate law can only be calculated from the reaction's slowest or rate-determining phase, according to the first sentence.
(B) -The second statement is not entirely right, since we cannot evaluate an accurate rate law by simply looking at the net equation. It must be decided by experimentation.
(C) -Since there are two reactants, the third statement is correct: most bimolecular reactions are second order overall.
(D)-The fourth argument is incorrect. We must track the rates of and elementary phase that is following the reaction in order to determine the rate.
Therefore , the first and third statement is true.
How many moles of NaOH are contained in 56.0 mL of a 2.40 M solution of 1 point
NaOH in water? (**Use only numerical answers with 3 significant figures.
The units are given in the question.)
Your answer
Answer:
1.34 mol
Explanation:
Molarity, which is the molar concentration of a solution, can be calculated by dividing the number of moles (n) by the volume (V).
That is;
Molarity (M) = n/V
According to the information provided in this question;
M = 2.40M
V = 56.0 mL = 56/1000 = 0.056 L
Since molarity = n/V
number of moles = M × V
n = 0.056 × 24
n = 1.34 mol
HELP ASAP PLEASE!!! :)
Answer:
Alkane
Explanation:
Alkenes have CH in their condensed formulas and alkynes have C in their condensed formulas. There are only CH3 and CH2 so it's an alkane.
The dehydration of the alcohol functional group is a widely used reaction in organic chemistry. The mechanism is generally accepted to always operate via an ______ step-wise process. The _____ mechanism process will always produce (after dehydration) a ________________ style alkene as major product. The driving force for the production of this ________________ style alkene product is generally going to be determined by stability of the ________ ____________.
Answer:
EliminationEliminationZaitsevZaitsevCarbocationExplanation:
The mechanism is generally accepted to always operate via an ELIMINATION step-wise process. The ELIMINATION mechanism process will always produce (after dehydration) a ZAITSEV style alkene as major productThe driving force for the production of this ZAITSEV style alkene product is generally going to be determined by stability of the CARBOCATIONElimination mechanism is the removal of two substituents from a molecule in either a one- or two-step mechanism
Carbocation is a molecule containing a positive charged carbon atom and three bonds
The mechanism is generally accepted to always operate via an elimination step-wise process. The elimination mechanism process will always produce (after dehydration) a Zaitsev style alkene as major product. The driving force for the production of this Zaitsev style alkene product is generally going to be determined by stability of the carbocation.
What is dehydration?
Dehydration is a process in which a water molecule releases from the given compound to form an unsaturated compound.
Dehydration process of alcohol is done by the elimination reaction in which water molecule eliminate and due to this dehydration we get an unsaturated product alkene. This dehydration process is go through the formation of carbocation which in turn forms the product. Stability of the product is determined by the Zaitsev rule and according to this rule most substituted product is the major and stable product.
Hence correct options are: Elimination, elimination, Zaitsev, Zaitsev and carbocation.
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2. Some nitrogen at a pressure of 35.75 p.s.i is in a 100 L container. If the container's volume is reduced to 2250 ml then what is the resulting pressure?
Answer:
1455.6
Explanation: you first convert 2250ml to l by dividing by 1000 so you get 2.25l then you use Boyles law which is p1v1=p2v2 then insert values
35.75*100=p2*2.25 then divide both sides by 2.25 then you get 1455.6
The pressure can be increased by doing what?
A)increasing the force and decreasing the area
B)increasing the force and increasing the area
C)decreasing the force and increasing the area
D)none of the above
Iron has a density of 7.87 g/cm^3. What is the mass of 55.2 cm^3 of iron?
Answer: Formula: Mass = (Volume)(Density)
Iron Density = 7.87 g/cm^3
Volume of Iron = 55.2 cm^3
Mass=(V)(D)
Mass= (55.2 cm^3) x (7.87 g/cm^3)
Mass= 434,42 g
Explanation:
Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
What do you mean by density ?The term density is defined as the measurement of how closely a material is packed together.
It is also defined as the mass per unit volume. Density Symbol is D or ρ Density Formula is ρ = m/V, where ρ is the density, m is the mass of the object and V is the volume of the object.
Density is an important because it allows us to find out what substances will float and what substances will sink when placed in a liquid.
Formula:
Mass = (Volume)(Density)
Given:
Iron Density = 7.87 g/cm³
Volume of Iron = 55.2 cm³
Mass=(V)(D)
Mass= (55.2 cm³) x (7.87 g/cm³)
Mass= 434,42 g
Thus, Iron has a density of 7.87 g/cm³. 434,42 g is the mass of 55.2 cm³ of iron.
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Do nitrates always form precipitates?
Answer:
Nitrates compared to sulphates are much more soluble therefore won't form precipitates easily.
The solubility of a solid in a liquid generally increases with increase temperature.
True
Or
False
Answer:
False, Solubility increases with temperature for most solids.
Explanation:
All light travels at the same speed.
O True
O False
Answer:
False
Explanation:
It depends on wixh kid of light is it
Example
Sun light difders from lamp light
Why does a red object appear red?
O A. It reflects light of wavelengths other than red.
OB. It absorbs light of red wavelengths.
O C. It absorbs light of wavelengths other than red.
O D. It reflects infrared radiation.
Right answers only for brainly
Answer:
Objects appear different colours because they absorb some colours (wavelengths) and reflected or transmit other colours. ... For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum
A red object appear red because it absorbs light of wavelengths other than red. Therefore, option C is correct.
What is wavelength ?The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).
A transverse wave's wavelength is defined as the distance between two adjacent crests. A longitudinal wave's wavelength can be calculated as the distance between two adjacent compressions.
The wavelengths that are reflected or transmitted are what we see as colors. A red shirt, for example, appears red because the dye molecules in the fabric have absorbed light wavelengths from the violet/blue end of the spectrum. The only light reflected from the shirt is red light.
Thus, option C is correct.
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How many significant figures are in the number 420,000 mi?
Answer:
2
Explanation:
zeros are not considered sig figs
Easy question please help.
Answer:
1 km an hour
Explanation:
i mean its pretty easy like you said if at 4 hours its traveled 4 km then its going 1 km an hour and at 10 its gone 10 km
most sedimentary rock forms in the ocean.This is because oceans-
Answer:
Explanation:
are where most bits of broken rock are deposited.
This is because oceans are where most bits of broken rock are deposited.
If an equilibrium mixture of the three gases at 600K contains 2.92*10^-2 M COCH(g) and 1.76*10^2 M CO, what is the equilibrium
concentration of Cl2?
Answer:
C
Explanation:
What are the products for
Answer:
[tex]ZnCO_3(s)+2KNO_3(aq)[/tex]
Explanation:
Hello there!
In this case, for the referred reactants side, we can evidence that this is a double displacement reaction whereby Zn gets bonded with CO3 and therefore K gets bonded with NO3 to yield:
[tex]Zn(NO_3)_2+K_2CO_3\rightarrow ZnCO_3+2KNO_3[/tex]
Whereas the KNO3 product is aqueous and the ZnCO3 is solid due to the corresponding solubility rules. Thereby, the answer is the third one.
Regards!
Why do scorpions glow on a black light?
Answer:
All scorpions fluoresce under ultraviolet light, such as an electric black light or natural moonlight. The blue-green glow comes from a substance found in the hyaline layer, a very thin but super tough coating in a part of the scorpion's exoskeleton called the cuticle
Explanation:
Answer:
All scorpions fluoresce under ultraviolet light, such as an electric black light or natural moonlight. Much like many other creepy, crawly insects, scorpions like hiding in dark places. ... If you're worried that you may have a scorpion problem, you can use a black light to search for them at night. When a black light hits a scorpion, the proteins on its exoskeleton create a bright neon blue hue.Scorpions do not like heat and bright light. They lose some of what little water they have to evaporation. So they use their sensitivity to UV rays to determine if it's dim enough for them to crawl out and get to business. He thinks that scorpions glow to convert the dim UV light from the moon and the stars into the colour that they see best – blue-green. This could explain why scorpion eyes are so exquisitely sensitive, to the point where they can detect the faint glow of starlight against the background of the night sky.Given the high densities of scorpions in some areas, their importance in ecological food webs, particularly with respect to helping control insect populations, is considerable. Many are sensitive to environmental degradation and are considered equilibrium species. Ecology: Scorpions are primarily nocturnal.Scorpions are preyed upon by large centipedes, tarantulas, lizards, birds (especially owls), and mammals such as bats, shrews, and grasshopper mice.
Explanation: I added a little more info about them please give me brainliest
As mentioned in the kinetic molecular theory, what is the main reason that the volume of gas particles can be considered zero?
a)The bonds present in gas particles are stronger than other bonds, pulling atoms in closer to each other, causing a shorter bond length which greatly decreases the volume.
b)When atoms enter the gas phase, they are less affected by gravity, which lowers their mass and in turn, their volume.
c)The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained.
Answer:
The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained
Explanation: