mendeleev arranged the elements in order of increasing relative atomic mass. When he did this he noted that the chemical properties of the elements and their compounds showed a periodic trend
Answer:
Left to right
Elements are arranged by increasing atomic mass
The vapor pressure of carbon disulfide is 355.6 torr at 25°C. What is the vapor pressure of a solution prepared by dissolving 10.60 g naphthalene (C10H8, Molar Mass = 128.2 g/mol) in 155 mL CS2 liquid (Molar Mass = 76.14 g/mol, density = 1.261 g/mL)? Assume the solution obeys Raoult's law, and treat naphthalene as a nonvolatile solute.
Answer:
344.5764 torr
Explanation:
Molar mass of naphthalene = 128.2g/mol
Mass of naphthalene = 10.60 g
Carbon disulfide:
Molar mass= 76.14g/mol ;
volume = 155mL ;
density = 1.261 g/mL
Vapour pressure = 355.6 torr
Number of moles = mass / molar mass
CS2:
Mass = density × volume
Number of moles = (density × volume) / molar mass
Number of moles = (1.261 * 155) / 76.14 = (195.455 / 76.14) = 2.567 moles of CS2
Number of moles of C8H10:
Number of moles = 10.60 / 128.2 = 0.083 C8H10
Total number of moles :
2.567 + 0.083 = 2.65 moles
Mole fraction of each compound in solution :
CS2 :
2.567 / 2.65 = 0.969
C8H10:
0.083 / 2.65 = 0.031
According to Raoult's:
Psolution = Xsolvent × Posolvent
CS2 = solvent
Xsolvent = Mole fraction of solvent
Posolvent = Vapour pressure of pure solvent
Psolution = 0.969 × 355.6 torr = 344.5764 torr
The vapor pressure of the solution would be as follows:
[tex]344.5764[/tex] torr
Given that,
Vapor pressure of Carbon Disulfide [tex]= 355.6[/tex] torr
[tex]volume = 155mL ;[/tex]
[tex]density = 1.261 g/mL[/tex]
Naphthalene's mass [tex]= 10.60 g[/tex]
Naphthalene's molar mass [tex]= 128.2g/mol[/tex]
Now,
We know that
Number of moles [tex]= mass/molar mass[/tex]
Mass [tex]= density[/tex] × [tex]volume[/tex]
[tex]Number of moles =[/tex] [tex](density[/tex] × [tex]volume) / molar mass[/tex]
So,
Number of moles of Carbon Disulfide [tex]= (1.261[/tex] × [tex]155) / 76.14[/tex]
[tex]= (195.455 / 76.14)[/tex]
[tex]= 2.567[/tex] moles of Carbon Disulfide
Number of moles of Naphthalene:
Number of moles [tex]= 10.60 / 128.2[/tex]
[tex]= 0.083[/tex]
Now,
Total number of moles :
[tex]2.567 + 0.083[/tex]
[tex]= 2.65[/tex] moles
Mole fraction of each compound in solution :
Carbon Disulfide:
2.567 / 2.65
[tex]= 0.969[/tex]
Naphthalene
0.083 / 2.65
[tex]= 0.031[/tex]
According to Raoult's:
P[tex]solution = Xsolvent[/tex] × [tex]Posolvent[/tex]
Carbon Sulfide = Solvent
[tex]Xsolvent =[/tex] Mole fraction of solvent
[tex]Posolvent =[/tex] Vapour pressure of the pure solvent
[tex]Psolution[/tex] [tex]= 0.969[/tex] × [tex]355.6 torr[/tex]
[tex]= 344.5764[/tex] torr
Thus, "[tex]344.5764[/tex] torr" is the correct answer.
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Write 0.00103 in scientific notation
Answer:
1.03
Explanation:
You would take 0.00103 and move the decimal like this; 0001.03, we wouldn't have the zeroes in front of the one, as it can throw us off. Therefore, your answer would be 1.03.
Hope I helped! Don't hesitate to let me know if I made a mistake.
What is the answer? Please
Answer:
To instill a high degree of personal honor, self-reliance, and confidence in each cadet by presenting a military environment in which cadets will be forced to rely upon themselves and their shipmates to study, work, and learn.
A beaker can hold 200 cm3 of water. When it's empty, how
many liters are needed to refill it?
L
Answer:
[tex]V=0.200L[/tex]
Explanation:
Hello,
In this case, since the volumetric capacity of the beaker is 200 cm³, by considering that 1000 cm³ equals 1 L, the liters are then computed via the following unit conversion:
[tex]V=200cm^3*\frac{1L}{1000cm^3}\\ \\V=0.200L[/tex]
Best regards.
A certain element XX has four isotopes. 5.845% of XX has a mass of 53.93961 amuamu. 91.75% of XX has a mass of 55.93494 amuamu. 2.123% of XX has a mass of 56.93539 amuamu. 0.2820% of XX has a mass of 57.93328 amuamu. What is the average atomic mass of element XX? Express your answer numerically to four signif
Answer:
55.85 amu
Explanation:
Let A, B, C and D represent the four isotopes of element X.
The following data were obtained from the question:
Isotope A:
Abundance (A%) = 5.845%
Mass of A = 53.93961 amu
Isotope B:
Abundance (B%) = 91.75%
Mass of B = 55.93494 amu
Isotope C:
Abundance (C%) = 2.123%
Mass of C = 56.93539 amu
Isotope D:
Abundance (D%) = 0.2820%
Mass of D = 57.93328 amu
Average atomic mass of element X =.?
The average atomic mass of X can be obtained as follow:
Average Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100] + [(Mass of D × D%)/100]
Average Atomic mass = [(53.93961 × 5.845)/100] + [(55.93494 × 91.75)/100] + [(56.93539 × 2.123)/100] + [(57.93328 × 0.2820)/100]
= 3.15277 + 51.32031 + 1.20874 + 0.16337
= 55.84519 ≈ 55.85
Therefore, the average atomic mass of X is 55.85 amu
Which of the following would have the largest pKa?
a. CH3CH2NH+3
b. C6H5NH+3
c. C6H5NH2
d. CH3CH2NH2
Answer:
CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
Explanation:
To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:
pKa of CH3CH2NH3+ = CH3CH2NH2; C6H5NH3+ = C6H5NH2
Also, Kw / Kb = Ka
Thus:
pKa of CH3CH2NH3+/CH3CH2NH2 is:
Kw / kb = Ka = 1.79x10⁻¹¹
-log Ka = pKa
pKa = 10.75
pKa of C6H5NH3+/ C6H5NH2 is:
Kw / kb = Ka = 2.5x10⁻⁵
-log Ka = pKa
pKa = 4.6
That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
Which statement describes a property that is unique to metalloids?
Metalloids are shiny.
Metalloids are semiconductive.
Metalloids are solid.
Metalloids are brittle.
Answer:
Metalloids are semiconductive.
Explanation:
Answer: Metalloids are semiconductive.
How many neutrons are there in 8 molecules of
[tex] \frac{19}{9} f2[/tex]
Answer:
128 neutrons
Explanation:
How many neutrons are there in 8 molecules of [tex]^{19} _9 F_2[/tex]?
Step 1: Calculate the number of neutrons in 1 atom of F.
The atomic number (z) of F is 9 and its mass number (A) is 19. We can calculate the number of neutrons using the following expression.
n⁰ = A - Z = 19 - 9 = 10
Step 2: Calculate the number of neutrons in 1 molecule of F₂.
1 molecule of F₂ contains 2 atoms of F. The number of neutrons in 1 molecule of F₂ is:
(8 n⁰/1 atom F) × (2 atom F/1 molecule F₂) = 16 n⁰/1 molecule F₂
Step 3: Calculate the number of neutrons in 8 molecules of F₂
8 molecule F₂ × 16 n⁰/1 molecule F₂ = 128 n⁰
Brian's aunt has cats. When Brian recently visited her, he started sneezing badly and believes that it was because
he is allergic to cats.
What would be the next step for Brian to form a hypothesis?
O by avoiding going to his aunt's house
by wearing a nose mask near cats
by visiting other households with cats
O by visiting his aunt's house again with the cats outside
Answer:
By visiting other households with cats.
Explanation:
This will give Brian a variety of other houses and determine if it is truly cats or just alleries from other items. This is the most direct way to get Brian the answer he is looking for.
Answer:
c
Explanation:
i just did it
What is the solubility product expression for Zn3(PO4)2?
Answer:
[tex]Ksp=[Zn^{2+}]^3[PO_4^{3-}]^2[/tex]
Explanation:
Hello,
In this case, since the equilibrium dissociation of zinc phosphate is:
[tex]Zn_3(PO_4)_2(s)\rightleftharpoons 3Zn^{2+}(aq)+2(PO_4)^{3-}(aq)[/tex]
Due to the fact that only the zinc and phosphate ions are in aqueous state, the solubility product expression is written considering the law of mass action in which the concentration of each species is powered to the corresponding stoichiometric coefficient as follows:
[tex]Ksp=[Zn^{2+}]^3[PO_4^{3-}]^2[/tex]
Best regards.
19) What did Rutherford's experiment show?
Answer:
experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus.
Explanation:srry im late but i dont be on it like that hoped it helped tho srry
Can someone help me with example #1 please
Answer: 343 K
Explanation:
To convert Celsius to Kelvin, you would add 273 to Celsius.
70°C+273=343 K
Now, we know that 70°C is 343 K.
Please help need ASAP!!! Due tonight,
Name the Compounds. Spelling counts
SiCl4
N2O4
Answer:
Silicon tetrachloride
Dinitrogen tetroxide
The name of the compound SiCl₄ is named silicon tetrachloride and N₂O₄ is named dinitrogen tetroxide.
SiCl₄ is named silicon tetrachloride. It is composed of one silicon atom (Si) bonded to four chlorine atoms (Cl). The prefix "tetra-" indicates the presence of four chlorine atoms bonded to the central silicon atom.
N₂O₄ is named dinitrogen tetroxide. It consists of two nitrogen atoms (N) bonded to four oxygen atoms (O). The prefix "di-" indicates the presence of two nitrogen atoms, and the suffix "-tetraoxide" indicates the presence of four oxygen atoms.
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Hover over answer image to enlarge
8)
Which part of the atom cannot have its location accurately determined and is modeled by a cloud around the center of
the atom?
-0)
A)
electron
B)
neutron
nucleus
D)
proton
An atomic nucleus is composed of
)
How many Ethers were in existence at launch and why? 1. 21 million because they wanted to have more units than Bitcoin 2. 72 million because they couldn't make any less 3. 72 million because they needed to raise cash for its development 4. 21 million because they needed some to use on the testnet
Answer:
72 million because they needed to raise cash for its development
Explanation:
It is a known fact that at lunch Ethereum had only 72 million tokens in existence back in July 2015. In other to develop the Blockchain network further, the founder, Vitalik Buterin organized a fundraising event around July and August 2014.
Fast forward to the year 2020, Ether now has a total supply of about 112 million.
3. Diesel fuel has a density of 0.839g/mL What is the volume, in gallons, of 2.3 kg of diesel? [1 gallon = 3.79 L)
Answer:
0.71 gal
Explanation:
Step 1: Given data
Density of Diesel (ρ): 0.839 g/mL
Mass of Diesel (m): 2.3 kg
Step 2: Convert "m" to grams
We will use the relationship 1 kg = 10³ g.
2.3 kg × (10³g/1 kg) = 2.3 × 10³ g
Step 3: Calculate the volume (V) of the Diesel sample
We will use the density formula.
ρ = m/V
V = m/ρ
V = 2.3 × 10³ g/(0.839 g/mL)
V = 2.7 × 10³ mL
Step 4: Convert "V" to L
We will use the relationship 1 L = 10³ mL.
2.7 × 10³ mL × (1 L / 10³ mL) = 2.7 L
Step 5: Convert "V" to gal
We will use the relationship 1 gal = 3.79 L.
2.7 L × (1 gal/3.79 L) = 0.71 gal
Answer:
2.3 kg x1000 g/kg = 2300 g
2300 g x 1 ml/0.839 g = 2741 ml
2741 ml x 1 L/1000 ml = 2.741 L
2.741 L x 1 gal/3.79 L = 0.72 gallons
Explanation:
3 H2S + 2AuCl --> Au2S3 + 6 HCL is what type
of reaction
Answer:
Double Displacement (Metathesis)
Explanation:
Define self reduction reaction.
Answer:
Self-reduction is a reaction in which no external reducing agent is required. It is called self-reducing because copper oxide itself reduced the copper sulfide to give copper and sulfur dioxide.
Which pair of elements have chemical properties that are most similar
[tex]\text{Hello there! :)}[/tex]
Answer:
[tex]\large\boxed{(B)}[/tex]
Elements on the periodic table that are the closest in characteristics are in the same group, or column.
Looking at the answer choices, the only two pairs of elements that are in the same group are (B) Al and Ga, as well as (D) F and I.
On the periodic table, Al (Aluminum) and Ga (Gallium) are only one period (row) away from each other, while F (Flourine) and I (Iodine) are 3 periods away.
***Periods determine the number of energy levels and other properties, so elements that are closer to each other would have more similar properties.
Therefore, Aluminum and Gallium contain the most similar chemical properties.
Which of the following correctly describes a way in which Earth's atmosphere interacts with the biosphere
Answer:
Living organisms breathe gases in the atmosphere.
Explanation:
Answer:
Living organisms breathe gases in the atmosphere.
Explanation:
Biosphere
the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms.
Atmosphere
the envelope of gases surrounding the earth or another planet
To what volume (in mL) would you need to dilute 25.0mL of a 1.45 m solution of Kcl to make a 0.0245m solution of KCl
Answer:
The answer is
1479.60 mLExplanation:
In order to calculate the volume needed we use the formula
[tex]V_2 = \frac{C_1V_1}{C_2} [/tex]
where
C1 is the concentration of the stock solution
V1 is the volume of the stock solution
C2 is the concentration of the diluted solution
V2 is the volume of thevdiluted solution
From the question
C1 = 1.45 M
V1 = 25 mL
C2 = 0.0245 M
So we have
[tex]V_2 = \frac{1.45 \times 25}{0.0245} = \frac{36.25}{0.0245} \\ = 1479.59...[/tex]
We have the final answer as
1479.60 mLHope this helps you
what is biotic?check all that apply
Answer: biotic is Living things in their ecological relations.
Explanation:
The two forces acting on a boat or some other floating object are________
and gravity.
Answer:
buoyancy. ...
Explanation:
........
Answer:
buoyancy
Explanation:
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An example of an extensive physical property is
Group of answer choices
mass
density
boiling point
melting point
Answer:
Mass and density is the answer?
The temperature at which carbon dioxide sublimes is about 195 K. What is this
temperature in units of degrees Celsius?
-78° Celsius is the temperature in units of degrees Celsius.
What is temperature?Temperature is the measure of hotness or coldness expressed in terms of any of several scales, including Fahrenheit and Celsius.
195 Kelvin = 195 - 273.15 = -78.15 Celsius.
-78° Celsius is the temperature in units of degrees Celsius.
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The uncertainty in the measurement 0.0035 mg is:_______ A) + 0.1 mg B) + 0.01 mg C) 0.001 mg D) + 0.0001 mg
Answer:
The correct option is (D).
Explanation:
Uncertainty means lack of certainty in any calculations. It is the quantification of doubts after the calculations are done.
In this problem, we need to find the uncertainty in the measurement 0.0035 mg. There are 4 numbers after decimal. It means uncertain digit 1/10000 is the smallest scale division.
Hence, the uncertainty in the measurement 0.0035 mg is +0.0001 mg
A jet airplane flies from St. Louis, Missouri, to Phoenix, Arizona, in 3 hrs. The distance is
1,500 miles. What is the plane's speed ?
Answer:
Distance = 1500miles
time taken = 3 hours
speed of plane = distance/time taken = 1500/3= 500milesperhour
Explanation:
According to the distance formula , the speed of the plane is 500 miles per hour.
What is speed?The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit interval of time indicating that it is thus a scalar quantity.The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity.
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or in the US and the UK, miles per hour (mph).
Here, speed is calculated as distance /time= 1500/3= 500 miles per hour.
Thus, the speed of plane is 500 miles per hour.
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BRAINLIEST PLEASE HELP WITH THIS CHEMISTRY QUESTION!!
Which of the following describes how further studies supported the work done by Ernest Rutherford?
Answer: James Chadwick discovered neutral particles in the nucleus. So your answer is C
Explanation:
I just took a pretest and I had this same question and I got it right
Answer:
James Chadwick discovered neutral particles in the nucleus.
Using the brønsted theory, classify the compounds as either an acid or a base
1. HCOO-
2. HNO3
3. -CH3COOCH3
4. HCOOH
Answer:
all the below are ACIDS
Explanation:
1.HCOO- Formate
HCOO- is a conjugate base.
2.HNO3- Nitric Acid
Acid
3.CH3COOCH3: Methyl acetate
Acid
4. HCOOH: Formic Acid
Acid
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How do you find the average density?
Answer:
total mass divided by its total volume
Explanation: