Answer:
First, the direct method requires recording the total mass of solution, and then evaporating off the solvent. The solid left behind is the solute, which is then weighed and used to calculate mass percent. Density can also be used to determine the mass percent of an unknown concentration.
in my opinion:)
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
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.
Learn more about speed,here:
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(01.04 LC)
What phase of matter has particles that are held together but can flow past each
other and takes the shape of a container, filling it from the bottom up? (3 points)
1) Gas
2) Liquid
3) Plasma
4) Solid
how do you tell if an chemical eqaution is unbalanced
3 H2S + 2AuCl --> Au2S3 + 6 HCL is what type
of reaction
Answer:
Double Displacement (Metathesis)
Explanation:
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 do you find the average density?
Answer:
total mass divided by its total volume
Explanation:
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
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.
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.
Learn more about "Pressure" here:
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Which of the following isotopes are NMR inactive?
a. 1H
b. 12C
c. 15N
d. 16o
e. 19F
f. 31P
Answer:
12C and 16O
Explanation:
Here, we want to select which of the options are NMR inactive. For an isotope to be NMR inactive, then the net nuclear spin is zero.
What this means is that the number of proton present coupled with the number of neutrons are an even number pair.
What we are saying here is that the number of protons is an even number while the number of neutrons too is an even number. So the net nuclear spin in this case is zero.
in the case of oxygen, we have 8 protons and 8 neutrons. This makes the nuclear spin zero and consequently makes the isotope NMR inactive.
Same is in the case of carbon. There are 6 protons and 6 neutrons and this also makes nuclear spin zero .
In all the other isotopes in the question, we have odd number even number or even number odd number pairs of protons and neutrons.
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.
When Z-4,5-dimethyloct-4-ene is treated with hydrogen chloride, HCl, the result is:________.
A. 4 stereoisomers
B. None of these
c. a pair of diastereomers
D. a racemic mixture OS a meso compound
Answer:
The correct option is c
Explanation:
The chemical equation for the reaction of Z-4,5-dimethyloct-4-ene and HCl is shown on the first uploaded image
Now looking at the product we see that there are two who has four different groups attached to them this carbon are known as chiral carbons hence the product formed is a pair of diastereomers
Not divisible
O atom
O compound
O mixture
O solution
Answer:
mixture or atom
Explanation:
I HOPE IT WILL HELP YOU
Explanation:
and ,answer is mixture.
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:
How do you scientist learn about the moon in other planets
Answer:NASA's Lunar Atmosphere and Dust Environment probe, for instance, orbits the moon and collects information about its atmosphere and surface. This important data can help scientists learn more about moons, asteroids and other objects in the solar system.
Explanation:
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.
Consider the following balanced equation:3Ca(NO3)2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaNO3(aq)If 24.2 moles of Na3PO4(aq) reacts with an excess of Ca(NO3)2(aq) to produce 50.6 moles of NaNO3(aq), what is the percent yield of the reaction?
Answer:
69.7% is percent yield
Explanation:
Based on the reaction:
3Ca(NO3)2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaNO3(aq)
2 moles of Na3PO4 react producing 6 moles of NaNO3.
As 24.2 moles of Na3PO4 react, theoretical moles of NaNO3 produced are:
24.2 moles Na3PO4 * (6 moles NaNO3 / 2 moles Na3PO4) =
72.6 moles of NaNO3
As there are produced 50.6 moles of NaNO3, percent yield is:
50.6 moles NaNO3 / 72.6 moles NaNO3 =
69.7% is percent yieldWrite 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.
why do NH3 and SO3 have different bond angles, even though they have the same number of atoms?
Answer:
Due to different atoms and different values of electronegativities.
Explanation:
NH3 and SO3 have different bond angles because both molecules have different type of atoms combine together. In NH3, nitrogen react with hydrogen while in SO3, sulfur react with oxygen atom. The bond angle of NH3 is 107 while the bond angle of SO3 is 120. This difference in bond angle is also due to different electronegativities of the bonded atoms. The electronegativity of oxygen is higher than hydrogen so repulsion of hydrogen is less and that's why its bond angle is also lower than oxygen.
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
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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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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If your front lawn is 25.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1350 new snowflakes every minute, how much snow, in kilograms, accumulates on your lawn per hour? Assume an average snowflake has a mass of 1.90 mg.
Answer:
19.17 kgExplanation:
calculate area of lawn
25 * 20 = 500 sq ft
calculate how many flakes fall per minute
500 * 1150 = 575 , 000 flakes/minute
convert per minute rate to per hour rate
575 , 000 * 60 = 34 ,500 , 000 flakes/hour
now you know how many flakes feel in that one hour so we can now weigh them
34 , 500 , 000 / 1.8 = 19 , 166 , 667 mg (rounded)
convert to kilograms
19 , 166 , 667 / 100 , 000 = 19.17 kg (rounded)
3 points
What is the energy (Joules) of violet light with a frequency = 3.43 x 10^14
1/s? *
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
O 2.27 x 10^-19 J
Pls help me
Answer:
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
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.
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
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.
what is biotic?check all that apply
Answer: biotic is Living things in their ecological relations.
Explanation:
You left a glass full of water by a window in your house in the morning. Three hours later you walk by the glass, and the water level is significantly lower than it was in the morning. You have made the observation that the water level in the cup is lower. Then, you ask the following question: “Why is the water level in the cup lower?” What is a possible hypothesis you could make?