Answer:
D.All three graph lines peak over the same few weeks of winter.
Explanation:
took the test
Why is it necessary to add concentrated HCl, then water, rather than a solution of HCl to the eudiometer tube
If we add water to a concentrated acid, then the solution may boil very violently, splashing concentrated acid. If add acid to water, the solution that forms is very dilute and a small amount of heat is released.
Why do we add acid to water?When a strong acid is poured into water, it flows down the flask and mixes much better, so no boiling takes place. The addition of water to acid forms an extremely concentrated solution of acid initially. A large amount of heat is released and the solution may boil very violently, splashing concentrated acid out of the beaker and all this because the reaction is exothermic in nature.
The reason this takes place is due to a large amount of energy liberated in the hydration reaction of concentrated ions. Therefore, we add acid to water dropwise for the dilution with constant stirring and not water to acid directly.
If we add water to acid, then an exothermic reaction occurs and the solution may boil very violently. To form the dilute solution of any strong acid, you should add acid to water and the small amount of heat released is not sufficient to vaporize and spatter it.
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The atomic masses of 20Ne (90.48 percent), 21Ne (0.27 percent), and 22Ne (9.25 percent) are 19.9924356, 20.9938428, and 21.9913831 amu, respectively. Calculate the average atomic mass of neon. The percentages in parentheses denote the relative abundance
Answer:
20.180042 amu
Explanation:
From the question given above, the following data were obtained:
Isotope A (20Ne)
Mass of A = 19.9924356 amu
Abundance (A%) = 90.48%
Isotope B (21Ne):
Mass of B = 20.9938428 amu
Abundance (B%) = 0.27%
Isotope C (22Ne):
Mass of C = 21.9913831 amu
Abundance (C%) = 9.25%
Average atomic mass of Neon =.?
The average atomic mass of Neon can be obtained as follow:
Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]
= [(19.9924356 × 90.48)/100] + [(20.9938428 × 0.27) /100] + [(21.9913831 × 9.25) /100]
= 18.0891557 + 0.05668338 + 2.03420294
= 20.180042 amu
Therefore, the average atomic mass of Neon is 20.180042 amu
Question 2 of 25
Rain exists in which phase?
O A Liquid
O B. Solid
C. Plasma
D. Gas
Answer:
liquid
Explanation:
correct answer hope it helps
I need the answer multiple choice
Answer:
it's answer is
element of an atom ✌️
On average what is the time between collisions of a xenon atom at 300 K and (a) one torr pressure; (b) one bar pressure.
Answer:
(a). 132 × 10^-9 s = 132 nanoseconds.
(b)..176.5 pico-seconds.
Explanation:
(a). At one torr, the first thing to do is to find the speed and that can be done by using the formula below;
Speed = [ (8 × R × T)/ Mm × π]^1/2.
Where Mm = molar mass, T = temperature and R = gas constant.
Speed= [ ( 8 × 8.314 × 300)/ 131.293 × π × 10^-3)^1/2. = 220m/s.
The next thing to do now is to calculate for the degree of collision which can be calculated by using the formula below;
Degree of collision = √2 × π × speed × d^2 × pressure/ K × T.
Note that pressure = 1 torr = 133.32 N/m^2 and d = collision diameter.
Degree of collision = √2 × π × 220 × (4.9 × 10^-10)^2 × 133.32/ 1.38 × 10^-23 × 300.
Degree of collision = 7.55 × 10^6 s^-1.
Thus, 1/ 7.55 × 10^6. = 132 × 10^-9 s = 132 nanoseconds.
(b). At one bar;
1/10^5 × 10^3 × 56.65 = 1.765 × 10^-10 = 176.5 pico-seconds.
Which step is part of a scientific investigation?
O designing a solution
O implementing the solution
O evaluating the solution
O communicating the findings
An excess of oxygen reacts with 451.4 g of lead, forming 374.7 g of lead(II) oxide. Calculate the percent yield of the reaction.
Answer: The percent yield of the reaction is 77.0 %
Explanation:
[tex]2Pb+O_2\rightarrow 2PbO[/tex]
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
[tex]\text{Number of moles of lead}=\frac{451.4g}{207.2g/mol}=2.18moles[/tex]
[tex]\text{Number of moles of lead oxide}=\frac{374.7g}{223.2g/mol}=1.68moles[/tex]
According to stoichiometry:
2 moles of [tex]Pb[/tex] produces = 2 moles of [tex]PbO_2[/tex]
2.18 moles of [tex]Pb[/tex] is produced by=[tex]\frac{2}{2}\times 2.18=2.18moles[/tex] of [tex]PbO_2[/tex]
Mass of [tex]PbO_2[/tex] =[tex]moles\times {\text {Molar mass}}=2.18\times 223.2g/mol=486.6[/tex]
percent yield =[tex]\frac{374.7g}{486.6g}\times 100=77.0\%[/tex]
A 7.28 g sample of chromium metal was heated to produce chromium oxide. The weight of the compound was 10.63 g. What is the percent chromium in this compound?
Answer:
68.48%
Explanation:
The percent mass of an element in a compound tells us about the amount of such element contributed to the total compound.
In this case, 7.28 g sample of chromium metal was heated to produce chromium oxide with weight of 10.63 g. The percent mass of chromium in chromium oxide can be calculated by using the formula:
%mass of Cr = mass of Cr/mass of Chromium oxide × 100%
%mass of Cr = 7.28/10.63 × 100
%mass of Cr = 0.6848 × 100
%mass of Cr = 68.48%
Whenever the same two elements form more than one
compound, the different masses of one element that combine
with the same mass of the other element are in the ratio of
small whole numbers.
TRUE
FALSE
Answer:
The answer is true
Explanation: Because The law of multiple proportions states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.
List 5 foods that contain bacteria?
Which one of the following is NOT a proper unit for frequency? *
m·s–1
Hz
s–1
1/s
Answer:
m*s⁻¹.
Explanation:
Hello!
In this case, since the frequency measures how repetitive an event is per unit of time, for instance the laps a car drives every 5 minutes or something similar, we can infer it has units of event/time; in such a way, the unit m*s⁻¹ is not a proper unit of frequency because it is a proper unit of velocity which is the distance traveled per unit of time.
In such a way, Hz (hertz), s⁻¹ and 1/s are possible ways frequency can be represented.
Best regards!
every spring has an equilibrium position which statement describe a spring at it equilibruim position?
What color do you get if you mix red and blue light?
Red and Green?
Blue and green?
What relationship do you find between frequency and energy?
What relationship do you find between wavelength and current flow?
What relationship do you find between light intensity and current flow?
Answer:
Purple light.
Yellow light.
Explanation:
PLEASE HELP ME!!!!!!!!!!!!!!!!!!!
WRITE A SHORT PASSAGE ON HOW FIBRES ARE SPUN
HELPPP WILL MARK AS BRAINLIEST
Answer: Spun yarn is made by twisting staple fibers together
To make a cohesive thread Or “single”. Twisting fibers, into yarn in the process called spinning can be dated back to the upper Paleolithic. Yarn spinning was one of the first processes to be industrialized.
Explanation:
A Barometer reads 29.1 inches of mercury.Calculate this pressure in mmHg.
What is the answer?
This follows a simple conversion technique. Basically what the question is trying to say here is to convert 29.1 inHg to mmHg. 1 inHg is equal to 25.4 mmHg so 29.1 inHg would be equal to [tex]25.4 * 29.1[/tex] which when evaluated turns out to be: [tex]739.14[/tex]. :D
The pressure will be 739.14 mm Hg.
What is pressure?The SI unit measuring pressure would be the pascal, which measures the force of each unit area of the surface.
Calculation of pressure
It is known that 1inHg = 25.4 mm Hg.
Hence, the pressure = 25.4 × 29.1 = 739.14 mm Hg
Therefore, the pressure will be 739.14 mm Hg.
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The three lines in this Lewis dot structure represent the.
A)
three valence electrons of dinitrous oxide.
B)
six electrons in the triple bond of diatomic nitrogen.
C)
three electrons joining two nitrogen atoms in a diatomic molecule.
D)
three double bonds between the valence electrons of diatomic nitrogen.
Answer:
B) . six electrons in the triple bond of diatomic nitrogen
Explanation:
The three line in this Lewis dot structure represents the six electrons in the triple bond of diatomic nitrogen.
Nitrogen is made up of 7 electrons with 5 valence ones.
A lewis structure is made up of the symbol of the element surrounded by dot to represent the valence electrons.
In this nitrogen molecule, both species share 6 electrons. This makes each nitrogen atom isoelectronic with neon.
A scientist is considering formaldehyde (HCHO) for use in an experiment. She is studying the strength of triple bonds in molecules. Is
ormaldehyde a good choice for her to use? Why?
A. Yes, HCHO has three triple bonds.
B. Yes, HCHO has one triple bond.
C. No, HCHO has a double bond but no triple bonds.
D. No, HCHO has only single bonds.
HELP
What type of bond is formed between the carbon and either oxygen in CO2?
A) Single
B) Double
C) Triple
in the following chemical reaction between H_2 and Cl_2 to produce HCl, what is the sum of the mass of HCl produced plus the mass of left over reactants when 0.40 g of H_2 completely reacts with 12.35 g of Cl_2?
H_2(g) + Cl_2(g) → 2HCl(g)
Answer:
Left over mass of hydrogen = 0.06 g
Mass of HCl produced = 12.41 g
Explanation:
Given data:
Mass of H₂ = 0.40 g
Mass of Cl₂ = 12.35 g
Mass of left over reactant = ?
Mass of HCl produced = ?
Solution:
Chemical equation:
H₂ + Cl₂ → 2HCl
Number of moles of H₂:
Number of moles = mass / molar mass
Number of moles = 0.40 g/ 2 g/mol
Number of moles = 0.2 mol
Number of moles of Cl₂:
Number of moles = mass / molar mass
Number of moles = 12.35 g/ 71 g/mol
Number of moles = 0.17 mol
Now we will compare the moles of HCl with H₂ and Cl₂.
H₂ : HCl
1 : 2
0.2 : 2×0.2 = 0.4
Cl₂ : HCl
1 : 2
0.17 : 2 × 0.17 = 0.34
Chlorine is limiting reactant.
Mass of HCl produced:
Mass = number of moles × molar mass
Mass = 0.34 mol × 36.5 g/mol
Mass = 12.41 g
Leftover mass of hydrogen:
Cl₂ : H₂
1 : 1
0.17 : 0.17
Number of moles of H₂ react with Cl₂ are 0.17.
Moles remain unreacted = 0.2 - 0.17 = 0.03 mol
Mass left over:
Mass = number of moles × molar mass
Mass = 0.03 mol × 2 g/mol
Mass = 0.06 g
The sum of the mass of HCl produced plus the mass of left over reactants is:
Mass of hydrogen = 0.06 g
Mass of HCl = 12.41 g
Chemical ReactionGiven:
Mass of H₂ = 0.40 g
Mass of Cl₂ = 12.35 g
Mass of left over reactant = ?
Mass of HCl produced = ?
Chemical equation: H₂ + Cl₂ → 2HClNumber of moles of H₂:
Number of moles = mass / molar mass
Number of moles = 0.40 g/ 2 g/mol
Number of moles = 0.2 mol
Number of moles of Cl₂:
Number of moles = mass / molar mass
Number of moles = 12.35 g/ 71 g/mol
Number of moles = 0.17 mol
The moles of HCl with H₂ and Cl₂.
H₂ : HCl
1 : 2
0.2 : 2×0.2 = 0.4
Cl₂ : HCl
1 : 2
0.17 : 2 × 0.17 = 0.34
The chlorine is limiting reactant.
Mass of HCl produced:
Mass = number of moles × molar mass
Mass = 0.34 mol × 36.5 g/mol
Mass = 12.41 g
Leftover mass of hydrogen:
Cl₂ : H₂
1 : 1
0.17 : 0.17
Number of moles of H₂ react with Cl₂ are 0.17.
Moles remain unreacted = 0.2 - 0.17 = 0.03 mol
Mass left over:
Mass = number of moles × molar massMass = 0.03 mol × 2 g/molMass = 0.06 gLearn more about "Moles":
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The atom is one of the basic units of matter. Which part of the atom mostly determines the size of the atom?
a.Electrons
b.Nucleus
c.Neutrons
d.Protons
Answer:
Atomic size is the distance from the nucleus to the valence shell where the valence electrons are located. The separation that occurs because electrons have the same charge. The number of protons in the nucleus. The core electrons in an atom interfere with the attraction of the nucleus for the outermost electrons.
Explanation:
That would be B I believe, but please correct me if I'm wrong.
A baseball has serval properties. Write one property that a baseball has.
complete sentences.
A neutral atom becomes a positive ion when it
Answer:
Neutral atoms can be turned into positively charged ions by removing one or more electrons.
Explanation:
If there is an atom that has 9 protons and 9 electrons, removing an electron from the atom will gain a postive charge.
A 12 gram piece of Cu at 475 oC is placed in contact with a 15 gram piece of Cr at 265 oC.
Assume the two pieces of metal are the system and that there is no heat exchange between system and surrounding.
What is the final temperature of the two pieces of metal expressed in degree C?
Answer:
349.22°C
Explanation:
Let the final temperature of the two pieces of metal be x.
Now, the warmer metal which is C u reduces from 475°C to x. Thus Δt for C u is; Δt1 = 475 - x.
The cooler metal Cr increases in temperature from 265°C to x. Thus, it's change in temperature is Δt for Cr is; Δt2 = x - 265.
Now from conservation of energy, the amount of energy leaving the C u metal is equal to the amount of energy entering the Cr metal.
Thus;
q_lost = q_gain
Where;
q_lost = m1•c1•Δt1
q_gained = m2•c2•Δt2
Now, c1 & c2 are the specific heat capacity of C u and Cr respectively.
From online tables, c1 = 0.385 J/g°C and c2 = 0.46 J/g°C
We are given;
m1 = 12g and m2 = 15g
Thus;
12 × 0.385 × (475 - x) = 15 × 0.46 × (x - 265)
2194.5 - 4.62x = 6.9x - 1828.5
6.9x + 4.62x = 2194.5 + 1828.5
11.52x = 4023
x = 4023/11.52
x = 349.22°C
Will give brainliest, Look at the graph above. Compare it to the periodic table. What do you notice about the location on the periodic table of the elements that represent the high points
Answer:
We can see that the atomic radius decreases across every row.
Explanation:
I will comment more below.
The elements that represent the highest points on the graph are all elements of group 1 and occur at the head of the period to which they belong.
The periodic table is an arrangement of elements in groups and periods. The elements in the same group have the same number of valence electrons while the elements in the same period have the same number of shells.
Looking at the graph, we can see that the high points in the graph all correspond to the group 1 elements; sodium, potassium, rubidium and cesium.The have the highest atomic radii in the period. Atomic radii increases down the group but decreases across the period. Remember that these elements are at the head of the period to which they belong hence they have the highest atomic radii.
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What is the specific rotation of a sample of carvone that is an equal mixture of the R and S enantiomers
Answer:
Zero
Explanation:
An an equal mixture of the R and S enantiomers of carvone is called a racemic mixture.
In a racemic mixture, the R enantiomer rotates plane polarized light in one direction while the S enantiomer rotates plane polarized light in another direction.
This cancels out the rotation due to each enantiomer since they are equal in magnitude but opposite in direction leading to a specific rotation of zero for the racemic mixture.
When a material gains thermal energy and melts, it is undergoing a physical change.
Answer:
True, it undergoes a physical change.
Explanation:
A physical change is a change that does not change the chemical makeup of a material. This includes altering its shape.
TRUE OR FALSE? Alloys are used more than pure metals because they are generally softer and less likely to react with air or water. WILL GIVE BRAINLIEST
Answer:
False
Explanation:
They’re used cause they’re generally harder than pure metals
Alloys are used much more than pure metals because they are generally stronger and less likely to react with air or water...
So I would say false
4. Question: What effect does the amount of light have on plant growth?
Why does the flask have to be closed during the hydrochloric acid and sodium carbonate reaction?
Answer:
The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
Explanation:
The hydrochloric acid and sodium carbonate reaction was exothermic that caused the pressure to decrease. The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
In exothermic reactions, energy is produced in the form of heat or light.
A nuclear power plant is scheduled to undergo a retrofitting. What is the most likely outcome of the change?
The power plant will no longer generate radioactive wastes.
The power plant will recycle the water it uses to cool the reactor.
The power plant will be able to reprocess its used uranium fuel.
The power plant will switch from fission reactions to fusion reactions.
Answer:
It's B
Explanation:
I got it right on edjenuity
The most likely outcome of the retrofitting of a nuclear power plant is that it will be able to reprocess its used uranium fuel. Therefore, option C is correct.
What is nuclear power plant?A nuclear power plant is a facility that generates electricity by harnessing the heat produced by nuclear reactions. At the heart of a nuclear power plant is the reactor, where a controlled chain reaction of nuclear fission occurs.
Reprocessing is a process by which the used nuclear fuel is chemically treated to separate out and recover the unused uranium and plutonium, which can then be reused as fuel. This reduces the amount of radioactive waste produced by the plant and also extends the life of the uranium fuel.
The fission reactions to fusion reactions is not currently a viable option for power generation, and the idea that a retrofitting would eliminate radioactive wastes is unlikely, as nuclear power plants will always produce some amount of radioactive waste.
Thus, option C is correct.
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