Answer: D. False, it should read, "A theory and a law are already both supported by evidence and are equal, but they have different functions."
Explanation:
A "Theory" and a'' Law" in scientific method are already both supported by evidence but they have different function,
The function of " Theory" in scientific method is to give an explanation to the observations and findings gathered during the process. It can be modified, improved or even rejected as more information is being gathered.
While a '' Law '' tends to describe an observed event in nature that is true whenever it is put to test. It does not explain why the occurence or event is true.
What combination of substances will give a buffered solution that has a pH of 5.05? (Assume each pair of substances is dissolved in 5.0 L of water.) (Kb for NH3 = 1.8 ´ 10–5; Kb for C5H5N = 1.7 ´ 10–9) Select one: a. 1.0 mole NH3 and 1.5 mole NH4Cl b. 1.5 mole NH3 and 1.0 mole NH4Cl c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl e. none of these
Answer:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl
Explanation:
We can determine pH of a buffer using H-H equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] is concentration of conjugate base and [HA] concentration of weak acid. These concentrations can be computed as moles of each species.
We need to determine pKa of both NH₃ and C₅H₅N buffers, thus:
pKb = -log Kb
NH₃ pKb = -log 1.8x10⁻⁵ = 4.74
C₅H₅N pKb = -log 1.7x10⁻⁹ = 8.77
And pKa = 14 - pKb:
NH₃ pKa = 14 - 4.74 = 9.26
C₅H₅N pKb = 14 - 8.77 = 5.23
A buffer works only under pH's between pKa-1 and pKa + 1. As pKa NH₃ buffer is 9.23 is not possible to produce a buffer with pH 5.05 for this system.
Thus, we only will compute the buffers made with C₅H₅N:
c. 1.0 mole C5H5N (Weak base) and 1.5 mole C5H5NHCl (Conjugate acid)
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.0 moles] / 1.5 moles]
pH = 5.05d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.5 moles] / 1.0 moles]
pH = 5.41Right solution is:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHClFor the set of ionic compounds, LiCl, AgCl, PbCl2, choose the correct characterization of their solubilities in water from the response list. Group of answer choices All three salts are soluble. None of the three salts are soluble. Two of the three salts are soluble. One of the three salts is soluble.
Answer:
Two of the three salts are soluble.
One of the three salts is soluble.
Explanation:
One or two of the three salts would be soluble in water depending on if the water is cold or hot.
According to the solubility rules of chloride salts, all chlorides are soluble in cold water except for those of silver (Ag), lead (Pb), and mercury (I) (Hg).
This thus means that both AgCl and [tex]PbCl_2[/tex] would be insoluble in cold water while LiCl would be soluble.
[tex]PbCl_2[/tex] is, however soluble in hot water.
Hence, in cold water, one of the three salts (LiCl) would be soluble, while in hot water, two of the three salts (LiCl and [tex]PbCl_2[/tex]) would be soluble.
In a mass spectrometer, the ions are sorted out in which of the following ways?
A. By accelerating them through electric field
B. By accelerating them through magnetic field
C. By accelerating them through electric and magnetic field
D. By applying a high voltage
Answer:
C
Explanation:
The ions are first accelerated electrically, and then bended magnetically to sort them and record them.
absorption of digested food takes place in the
Answer:
Explanation:
Absorption of digested food takes place in the small intestine.
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Answer:
Absorption of digested food takes place in the small intestine.
Explanation:
An aerospace engineer is designing a rocket to have three stages. Which is
not a reasonable explanation for this decision?
A. To simplify the design of the rocket
O B. To decrease the mass of the rocket as it flies
C. To take advantage of the lesser amount of thrust needed in space
D. So the rocket only carries necessary mass
Answer:
A. To simplify the design of the rocket.
Explanation:
3 stage rockets require huge amounts of fuel when launched in order to last the entire voyage.
As the rocket flies, some compartments may be detached and fall away from the rocket, decreasing its mass (eliminating B, as it is reasonable). This is done so that the rocket only carries necessary mass, which doesn't include the used up rocket parts (eliminating D, as it is reasonable). When the rocket finally reaches space, the decrease in gravity means less thrust is needed, which is an important thing to take note of while designing the rocket (eliminating C, as it is reasonable).
A three stage rocket is very complex and has many features and mechanisms that are complicated to add and deal with. Giving a rocket, three stages is not a simplification, so A is the answer.
A. To simplify the design of the rocket
What is the best design for a rocket?At supersonic speeds (faster than the velocity of sound), the great shape is a narrower and sharper point. Rockets with a bigger diameter have greater drag because there's greater air being driven out of the manner.
Designing A Rocket In Six Easy Steps is given below
Step One: Know What Your Rocket Needs to Do. Step Two: Establish Mission Parameters. Step Three: Call in Experts. Step Four: Start Drawing. Step Five: Whittle Down the Possibilities. Step Six: Pick the Best Design.Learn more about rocket here: https://brainly.com/question/17833361
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Which statement about Schrödinger’s theory of the atomic model is true?
Answer:
it explain odds of finding the position of an electron.
A substance is followed by the symbol (I) in a chemical Equation. What does the symbol Represent
Answer:
Iodine
Explanation:
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Polymers formed from amino acids are called _____. proteins carbohydrates lipids nucleic acids
Answer:
Proteins
Explanation:
Amino acids act as monomers (a single unit used to form polymers) , the polymer will be a long chain of individual amino acids. An amino acid chain forms a protein. These proteins are also known as peptides.
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What are the properties of alkynes
Easyyy plz
What Is the Reactivity Series? ...
Answer:
In chemistry the reactivity series is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to the lowest.
Answer:
In a reactivity series, the most reactive element is placed at the top and the least reactive element at the bottom. More reactive metals have a greater tendency to lose electrons and form positive ions.
A reactivity series of metals could include any elements. For example,
A list of elements from most reactive to least reactive: potassium, sodium, lithium, calcium, magnesium, aluminum, zinc, iron, copper, silver, and gold.
A good way to remember the order of a reactivity series of metals is to use the first letter of each one to make up a silly sentence. For example, People Say Little Children Make A Zebra Ill Constantly Sniffing Giraffes.
Observations of the way that these elements react with water, acids, and steam enable us to put them into this series.
The tables show how the elements react with water and dilute acids:
Element Reaction with water
Potassium Violently
Sodium Very quickly
Lithium Quickly
Calcium More slowly
Element Reaction with dilute acids
Calcium Very quickly
Magnesium Quickly
Zinc More slowly
Iron More slowly than zinc
Copper Very slowly
Silver Barely reacts
Gold Does not react
Note that aluminum can be difficult to place in the correct position in the reactivity series during these experiments. This is because its protective aluminum oxide layer makes it appear to be less reactive than it really is. When this layer is removed, the observations are more reliable.
Non-metals in the reactivity series
It is useful to place carbon and hydrogen into the reactivity series because these elements can be used to extract metals.
Here is the reactivity series including carbon and hydrogen:
A list of elements from most reactive to least reactive: potassium, sodium, lithium, calcium, magnesium, aluminum, carbon, zinc, iron, hydrogen, copper, silver, and gold.
Note that zinc and iron can be displaced from their oxides using carbon but not using hydrogen. However, copper can be extracted using carbon or hydrogen. Displacement reactions of metal oxides
A more reactive metal will displace a less reactive metal from a compound. The thermite reaction is a good example of this. It is used to produce white-hot molten (liquid) iron in remote locations for welding. A lot of heat is needed to start the reaction, but then it releases an incredible amount of heat, enough to melt the iron.
aluminium + iron(III) oxide → iron + aluminium oxide
2Al + Fe2O3 → 2Fe + Al2O3
Because aluminum is more reactive than iron, it displaces iron from iron(III) oxide. The aluminum removes oxygen from the iron(III) oxide:
iron is reduced
aluminum is oxidized
Reactions between metals and metal oxides allow us to put a selection of metals into a reactivity series. Using metals A, B, and C:
Metal A Metal B Metal C
A oxide X Displaces A Displaces A
B oxide No reaction X No reaction
C oxide No reaction Displaces C X
Metal A cannot displace either B or C - so it must be the least reactive and be at the bottom of this reactivity series.
Metal B displaces both A and C - so it must be the most reactive and be at the top of this reactivity series.
Metal C displaces A but cannot displace B - so it must be more reactive than A but less reactive than B, and be in between them in this reactivity series.
In general, the greater the difference in reactivity between two metals in a displacement reaction, the greater the amount of energy released.
Aluminum is much higher than iron in the reactivity series, so the thermite reaction releases a lot of energy. Magnesium is very high in the reactivity series, and copper is very low - so the reaction between magnesium and copper oxide is more violent.
Therefore, the order is:
A list of letters from most reactive to least reactive: B, C and A,
Displacement reactions of solutions
A more reactive metal will displace a less reactive metal from a solution of one of its salts. For example:
magnesium + copper(II) sulfate → copper + magnesium sulfate
Mg(s) + CuSO4(aq) → Cu(s) + MgSO4(aq)
In this reaction, the blue color of the copper(II) sulfate fades as it is used up (magnesium sulfate solution is colorless). We would also see copper metal forming.
Reactions between metals and solutions of metal salts allow us to put a selection of metals into a reactivity series. Using metals J, K, and L:
Metal J Metal K Metal L
J sulfate X No reaction No reaction
K sulfate Displaces K X Displaces K
L sulfate Displaces L No reaction X
Metal J displaces both K and L - so it must be the most reactive and be at the top of this reactivity series.
Metal K cannot displace either J or L - so it must be the least reactive and be at the bottom of this reactivity series.
Metal L displaces K but cannot displace J - so it must be more reactive than K but less reactive than J, and be in between them in this reactivity series.
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A two digit number is such that the sum of the ones and the tens digits is tens.If the digits are reversed,the new number formed exceeds the originals numbers by 54.Find the number.
Answer:
Explanation:
Let the no in the ones place be x
And the no in the tens place be 10 - x
Original no = 10 ( 10 - x ) + x
= 100 - 10x + x
= 100 - 9x
Reversed no = 10 - x + 10 ( x )
= 10 - x + 10 x
10 + 9x
According to the question,
the new number formed exceeds the originals numbers by 54.
10 + 9x = 100 - 9x + 54
10 + 9x = 154 - 9x
By transposing,
9x + 9x = 154 - 10
18 x = 144
x = 144 / 18
x = 8
∴ Digit in ones place = x = 8
Digit in tens place = 10 - x = 10 - 8 = 2
So the number = 28
( You can also recheck it by adding the ones and tens digit
8 + 2 = 10
In the question, the sum of ones and tens digit in ten )
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how many significant figures are in 820 400.0 L
Answer:
7 significant numbers
3. Prepare a saturated solution of common salt in hot water. Suspend a thick cotton wick into this solution. Keep it undisturbed for a few days. You will find that common salt crystals will deposit on the wick. Is the change physical or chemical?
Answer:
physical
Explanation:
The change is physical.
A physical change involves a reversible change to the physical properties of substances, whereas a chemical change involves an irreversible change to the chemical properties of substances through a chemical reaction.
The dissolution of common salt is a physical change because the common salt can be retrieved by evaporating off the water. This is what was manifested by the deposition of common salt crystals on the wick.
How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
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Os subníveis mais energéticos de um dado átomo são: ...4s2 3d10 4p5 a) indique o seu número atomico b) quantos electrões de valência apresenta esse átomo c) a que família pertence?
Answer:
A. 35
B. 7
C. halogênios
Explanation:
Aqui, para responder a essa pergunta, precisaremos conhecer o elemento particular em questão.
..... 4s ^ 2 3d ^ 10 4p ^ 5 significa que está a cinco elétrons da configuração eletrônica do último elemento na primeira camada dos metais pesados.
O último elemento da 1ª série do elemento de transição é o zinco, portanto, como está a apenas 5 elementos de distância, o átomo de que estamos falando é o átomo de Bromo de Bromo.
A. O zinco tem um número atômico 30 e como o bromo está a 5 elementos de distância, seu número atômico é 35
B. Uma vez que pertence ao grupo halogênio, tem 7 elétrons de valência como o resto da família
C. Pertence à família dos halogênios
how many oxygen atoms are in 7.25g of calcium nitrate
Answer:
The answer to this question is approximately equal to 1.6 ×
[tex] 1.6 \times {10}^{23} atom \: o[/tex]
Please be I need this quick
2. For each pair of atoms determine which can steal an electron easier (higher electronegativity),
draw a picture of Bohr's model, and explain why:
a. Oxygen and Fluorine
b. Sodium and Potassium
c. Boron and Calcium
Answer: Option (A) is the correct answer.
Explanation:
An atom who has seven valence electrons in its ground state will have the following electronic configuration in its sub shells as 2, 7.
Thus, there will be in total 9 electrons and it is known that fluorine has atomic number 9.
Whereas sodium has 2, 8, 1 electrons in its sub-shell.
Calcium has 2, 8, 8, 2 electrons in its sub-shell and oxygen has 2, 6 electrons in its sub-shell.
Thus, we can conclude that out of the given options, fluorine is the element whose atom in the ground state has seven valence electrons.
What is the specific latent heat of fusion of ice if it takes 863 kJ to convert 4.6 kg of ice into water at 0 C?
Answer:
The correct answer is 187.7 J/Jg.
Explanation:
The formula for finding the specific heat of fusion is,
Specific heat of fusion = Q/m
Here Q is the heat energy added, signified in kJ, and m is the mass of the object in kg.
Based on the given information, the heat energy added or Q is 869 kJ and the mass of the ice is 4.6 Kg
Now putting the values in the formula we get,
Specific heat of fusion = Q/m
Specific heat of fusion = 863 kJ / 4.6 Kg = 187.7 J/Kg
3. How did ethanol use affect the shortage of corn available to consumers during and
after the drought of 2012? Do you think that commodities in one sector should be used
in another economic sector? How might the concept of needs and wants affect your
analysis of this issue?
Due to drought, the production of corn decreases and shortage of it occurs.
Effects of droughtYes, commodities in one sector should be used in another sector because scientist invented methods in which one commodity is used in several sectors for the production of new products.
Corn was used for the production of ethanol which causes the shortage of corn that was available to consumers during and after the drought condition of 2012 so we can conclude that due to drought, the production of corn decreases and shortage of it occurs.
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Atoms contain positive and negative charges. Why is the overall charge on an atom neutral?
A. Atoms contain the same amount of protons and electrons, and their charges cancel out.
B. The nucleus of an atom contains neutrons, which keep the positive and negative charges balanced.
C. Atoms are all negatively charged because electrons are on the outside of the atom.
D. Atoms contain the same amount protons and neutrons, and their charges cancel out.
Answer:
Atoms contain the same amount protons and neutrons, and their charges cancel out.
Explanation:
Answer via Educere/ Founder's Education
Atoms contain positive and negative charges, the overall charge on an atom neutral because Atoms contain the same amount of protons and electrons, and their charges cancel out.Hence, Option (A) is correct
What is an Atom ?
An atom is the smallest unit of ordinary matter that forms a chemical element.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms.
Atoms are extremely small, typically around 100 picometers across.
An atom consists of a positively charged nucleus, surrounded by one or more negatively charged particles called electrons.
The positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral.Hence, Option (A) is correct
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What is the molarity of a 50.0ml aqueous solution containing 10.0 grams of hydrogen peroxide H2O2
Molarity= No of moles of solute * 1000 / vol solution in ml
No of moles= Given mass / Molar mass
Given Mass of solute (H2O2)= 10g
Molar mass of H2O2=34gmol^-1
No of moles= 10/34= 0.294 moles
Volume of solution=50ml
Molarity = 0.294*1000 / 50
Molarity = 5.8M
The electron in a hydrogen atom can undergo a transition from n = 4 to n = 3, emitting a photon with energy 1.06 × 10 –19J. Use this transition to answer the following questions.
i. What is the wavelength of this transition?
ii. How does this transition show that the position of the electron is quantized?
Answer:
Wavelength (λ) = 1.875 × 10⁻⁶ m
Explanation:
Given:
Energy (e) = 1.06 × 10⁻¹⁹ J
Find:
Wavelength (λ) = ?
Computation:
e = hc / λ
λ = hc / e
where c = 3 × 10⁸
Planck's constant (h) = 6.625 × 10⁻³⁴
So,
Wavelength (λ) = (6.625 × 10⁻³⁴)(3 × 10⁸) / (1.06 × 10⁻¹⁹)
1. Wavelength (λ) = 1.875 × 10⁻⁶ m
2. Given n = 4 to n = 3 both are integer not fraction so, electron is quantize
You work in the special effects department of a movie studio. You are
currently working on a superhero movie where the hero is very strong
and can punch through metal. For the next scene you need to replace a
6 inch by 6 inch square of a metal wall with a different material that will
crumble when the actor hits it. What could you use?
A. You could use Carbon(C)
B. You could use Potassium (k)
C. You could use Titanium (T)
D. You could use Manganese (Mn)
Answer:
The correct option is;
D. Manganese (Mn)
Explanation:
Manganese is very brittle, hard, iron like silvery-gray metal, that is difficult to melt. In air, Manganese slowly disintegrate in a similar manner to iron rusting in water
Manganese and iron have similar chemical and physical properties however manganese is more harder and more brittle than iron
A brittle material is one that easily breaks without deforming elastically
Therefore, manganese, due to its very iron like appearance and brittle nature will be suitable to replace the metal wall and crumble easily when the actor hits it.
in the symbol 3p4
a. the 3 represents the principal energy level
b. the p represents the principal energy level
c. the 4 represents the principal energy level
d. all of the above
help!
Answer:
a. the 3 represents the principal energy level
Explanation:
3 is the principal energy level. The p is the sublevel. 4 is the possible occupying electron.
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Explanation:
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Which of the following is the correct chemical formula for Ca and F? CaF Ca2F CaF2
Answer:
CaF2
Explanation:
Calcium fluoride is a solid formed by the chemical combination of Calcium (Ca) and Fluorine (F). Two molecules of fluorine (F2) and one molecule of Calcium (Ca) are needed to form the Calcium Fluoride molecule.
An ionic bond is formed between the Calcium and Fluorine atoms i.e. electrons are transferred from calcium atoms to fluorine atoms. The calcium ion is a cation with formula; Ca2+ while fluorine is an anion with formula; F-. Hence, it takes two molecules of Fluorine ion (F-) to form a relatively stable and neutral molecule with 1 molecule of Calcium ion (Ca2+).
What are cells and how are they important to maintaining life?
Answer:
Cells are the "building blocks for all living things." Without cells, we couldn't survive. Cells do many important things. Some of the things they can do are taking in food nutrients, frame our bodies, and change the food nutrients into energy.
The pOH of a solution is 3.1. Which of the following is true about the solution? (1 point)
It is acidic and has a pH of 10.9.
It is basic and has a pH of 10.9.
It is acidic and has a pH of 6.2.
It is basic and has a pH of 6.2.
Answer:
The answer is option BExplanation:
To solve the question above we must first find the pH of the solution using the formula
pH + pOH = 14
pOH = 3.1
So we have
pH + 3.1 = 14
pH = 14 - 3.1
pH = 10.9
Since it's pH is 10.9 the solution is a basic solution since it's pH lies in the basic region.
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what are the efficient things needed for a village
Answer:
Those aspects which are something a village needs are specified beneath.
Explanation:
Things being equally necessary to make living simpler and therefore more enjoyable. The government has promised to continue providing basic facilities to either an unpopulated location, including such roads, drinkable water, as well as electric power. Therefore, throughout the village, certain things accessible with maximum variety and quality that have become the basic requirements for this human existence.A 46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
THIS IS THE COMPLETE QUESTION BELOW
46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?
Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)
molybdenum 10.28 2,623 4,639
mercury 13.53 -39 357
hafnium 13.31 2,233 4,603
lead 11.34 327 1,749
A.
molybdenum
B.
mercury
C.
hafnium
D.
lead
Answer :
The correct option is OPTION C.
(C) Hafnium
Explanation;:
We were given the mass of substance as (m) = 46.9 g
The Volume of substance as (V) = 3.5 Cm^3
But we know Density of substance.= Mass/it's Volume
Then Density=46.9/3.5
=13.4g/Cm^3
From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.
Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.
