Answer:
1 mole Of Helium = Weight of Helium/4Weight of Helium = 1*4 = 4 grams 1 mole of Helium contains 6.023*10²³ ( Avogadro number) atoms. Number of moles of in 4 grams of Hydrogen 4 grams is = given weight / molecular weight of Hydrogen (H₂) = 4/2 =2 Number of atoms/molecules in 2 moles of Hydrogen is (2*6.023*10²³) atoms. = 12.046*10²³ atoms.
(Hope this helps)
The number of atoms in 2 moles of helium is 1.204×10²⁴ atoms
From Avogadro's hypothesis,
1 mole of any substance = 6.02×10²³ atoms
Thus,
1 mole of helium = 6.02×10²³ atoms
With the above information in mind, we can obtain the number of atoms in 2 moles of helium as follow:
1 mole of helium = 6.02×10²³ atoms
Therefore,
2 moles of helium = 2 × 6.02×10²³ atoms
2 moles of helium = 1.204×10²⁴ atoms
Thus, we can conclude that 2 moles of helium contains 1.204×10²⁴ atoms
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Relate dark matter to the development of the universe after the Big Bang. In 3-5 sentences, speculate on how the development of the universe would have been different if there had been no dark matter. In your answer, use the term structures.
Please answer this and ill mark you as brainliest
Answer:
Dark matter also called baronic matter is the matter that makes up 27% of the universe.
In 1933 it was determined as that mass that cannot be seen, that is, the non-visible mass of outer space.
Dark matter also plays a central role in the formation of structures and the evolution of galaxies and has measurable effects on the anisotropy of cosmic microwave background radiation. The composition of this matter is unknown today.
The dark matter component has considerably more mass than the "visible" component of the Universe.
Explanation:
There are certain researchers who say that the appearance of dark matter was before the appearance of the big bang.
A relevant fact of this matter is that dark matter exerts gravity, and that gravity affects the movements of objects.
Despite the fact that nothing is known about its origin, astronomers have amply demonstrated that dark matter plays a determining role in the formation of galaxies and galactic clusters, which could not maintain their cohesion without its existence, but many doubt that it is the remainder / remnant or product of a big bang.
how many Atoms of chlorine Cl are there in 3.45 mol Cl?
Answer:
2.078x10^24
Explanation:
No. of atoms of chlorine = 3.45 x 6.022x 10 ^23 x 1
= 2.078x10^24
( to find no. of atoms of, heres the formula i was taught No. of atoms = no. of moles x Avogadros constant x no. of atoms in the formula of compound)
Which sentence best describes part of the process for generating electricity in a nuclear power plant?
A.Atoms Join together to produce water molecules.
B.An atom releases electrons, producing an electric current.
C.Protons and neutrons Join together to create atoms.
D.Heat is released when atomic nuclel split.
Answer:it is D
Explanation: it is only one that makes sense
aight imma let you guys i
Answer:
b
Explanation:
it is right
What is El Nino and La Nina explained? Please help fast
Answer:
el nino: the boy
la nina: the girl
Explanation:
Answer:
el nino is dinosour la nino is fishcat
Explanation:
What improvements have been made in modern farming? Select all that apply.
1. machines can do more work over less time
2. better seeds sprout and grow much more quickly
3. trains can transport food over long distances faster
4. trains can transport the machines to rural farms once built
5. insecticides used to keep insects off the crops
Answer:
all of them except number 2
Explanation:
Answer:
1,3,4,5 the other perosn is correct
Explanation: That what my quiz said
What is the correct answer? Please
Answer:
c
Explanation:
A community includes
A. all of the living organisms in a specific place at a specific time,
B. all plants, animals, minerals, and water in a specific place at a specific time,
C. only the plants in a specific place at a specific time.
D. only the animals in a specific place at a specific time.
Answer:
answer: A. all of the living organisms in a specific place at a specific time
Explanation:
Need help with these three pls!!!!!
The only thing that makes one kind of light different from another is it’s ____?
A) frequency
B) color
C) wavelength
D) temperature
what is an example of a strong base?
HCl
NaCl
NaOH
HF
Answer:
The answer is NaOH
Explanation:
Strong bases are characterized by the fact that they dissociate completely in an aqueous solution. In this case, sodium hydroxide, NaOH, is classified as a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Also, it is strong because it totally breaks in its ion. And the base which breaks totally in its atom called the strong base and which doesn't it that is a weak base.
Answer:
NaOH
Explanation:
Got it right in the test. Please mark as brainliest
How many joules are produced when 45 gram of copper is placed into water that releases them temperature from 12c to 71c (c)=0.75j/g*c
Answer:
Heat energy (Q) = 1.9925 KJ = 2 KJ (Approx)
Explanation:
Given:
Mass of copper (M) = 45 gram
Change in temperature (ΔT) = 71°C - 12°C = 59°C
Specific heat (c) =0.75 j /g*c
Find:
Heat energy (Q) = ?
Computation:
Heat energy (Q) = Mass(M) × Change in temperature (ΔT) × Specific heat (c)
Heat energy (Q) = 45 gram × 59°C × 0.75 j /g*c
Heat energy (Q) = 1991.25 J
Heat energy (Q) = 1.9925 KJ = 2 KJ (Approx)
Why is soap mixed with water?
O A. The soap turns the water molecules into a nonpolar solvent.
B. It covalently bonds to the water so it can be washed away.
O C. Its polar end mixes with the water so it can be washed away.
D. The soap becomes chemically active when mixed with water.
Answer:
Explanation:
Soap breaks up the oil into smaller drops, which can mix with the water. It works because soap is made up of molecules with two very different ends. One end of soap molecules love water - they are hydrophilic. The other end of soap molecues hate water - they are hydrophobic.
Answer:
C. Its polar end mixes with the water so it can be washed away.
Explanation:
Just took test
Which is usually associated with a faster reaction rate?
A. diluting a solution of the reactants
B. adding modeling clay to the reactants
C. removing heat energy from the reactants
D. using a solid with a high surface area in the reactants
Answer:
D. using a solid with a high surface area in the reactants, is your correct answer.
Explanation:
Using a solid with a high surface area in the reactants is usually associated with a higher reaction rate.
What is the mole fraction of Ba(OH)2 in an aqueous solution that contains 22.8% Ba(OH)2 by mass?
Answer:
0.03
Explanation:
22.8 g Ba(OH)2 (1 mol Ba (OH)2/ 171.34 g) = 0.133 mol Ba (OH)2
77.2 g H2O (1 mol H2O/18 g) = 4.29 mol H2O
X= molar fraction= mol Ba(OH)2/ mol total
X= 0.133/ (0.133+4.29) = 0.03
0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.
What is a mole fraction?The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.
Moles of [tex]Ba(OH)_2[/tex]
Moles = [tex]\frac{mass}{molar \;mass}[/tex]
Moles = [tex]\frac{22.8 g Ba(OH)_2}{171.34 g}[/tex]
= 0.133 mol [tex]Ba (OH)_2[/tex]
Moles of [tex]H_2O[/tex]
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]Moles = \frac{77.2 g H_2O}{18 g}[/tex]
= 4.29 mol [tex]H_2O[/tex]
The mole fraction of [tex]Ba(OH)_2[/tex]
[tex]\frac{mol Ba(OH)_2}{total \;mol}[/tex]
= 0.03
0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.
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Is the equation Zn+HCl > ZnCL2+H2 unbalanced or balanced
Answer:
unbalanced
Explanation:
Cl and H have an extra atom
- Hope that helps! Please let me know if you need further explanation.
What is the answer ?
Answer:
b
Explanation:
Electromagnetic waves are waves that have no medium to travel whereas mechanical waves need a medium for its transmission.
when the surface of a mirror curves inward, like the inside of a bowl, it is called a ____.
A) plane mirror
B) convex mirror
C) concave mirror
D) diffuse mirror
Answer:
C
Explanation:
The answer is always C
Answer:C. Concave mirror
Explanation:
When the surface of a mirror curves inward, like the inside of a bowl, it is called c. Concave mirror.
Which of these Electromagnetic waves has the most kinetic energy and can be
dangerous?
O radio waves
O gamma rays
O ultraviolet waves
O visible light
Answer:
Gamma Rays.
Explanation:
Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength.
Which of the following presents a safety hazard while working in the science laboratory?
A knowing how to use equipment
B wearing safety goggles
C following directions
D working alone
Answer:
D working alone
Explanation:
Working alone is the only option that could potentially be a safety hazard; if you have no one watching your back, errors could occur, like dropping glass or burning your hand, and no one is around to help you.
Choices A, B, and C are not correct because those are all good safety standards.
ASAP NEED HELP PLSSS
A gas occupying a volume of 3.75L at a pressure of 0.980 arm is allowed to expand at constant temperature until its pressure reaches 0.641 atm. What is the final volume of the sample?
Answer:
Volume = 5.73L
Explanation:
Data;
V1 = 3.75L
P1 = 0.980atm
P2 = 0.641atm
V2 = ?
This question involves the use of Boyle's law, which states that, the volume of a fixed mass of gas is inversely proportional to its pressure provided that temperature remains constant.
Mathematically,
V = kP, k = PV
P1V1 = P2V2 =P3V3=........=PnVn
P1V1 = P2V2
V2 = (P1 * V1) / P2
V2 = (0.980 × 3.75) / 0.641
V2 = 5.73L
The final volume of the gas is 5.73L
what are the possible values for standard temperature and pressure
Answer:
0 °C and 1 Atm,
Explanation:
Standard Temperature and Pressure. Standard temperature is equal to 0 °C, which is 273.15 K.
Standard Pressure is 1 Atm, 101.3kPa or 760 mmHg or torr
What Le Chatelier’s factors cause an increase in the concentration of Hb(CO)4(aq) in the Hb(CO)4(aq) + 4O2(g)Hb(O2)4(aq) + 4CO(g)
Answer:
Explanation:
Hb(CO)4(aq) + 4O2(g) ⇄ Hb(O2)4(aq) + 4CO(g)
1 ) If we increase the concentration of CO(g) , the reaction above will proceed in reverse direction to decrease its concentration, according to Le Chatelier principle. Hence more of Hb(CO)4(aq) will be formed.
2 ) If we decrease the concentration of O₂ , then also , reaction will proceed in reverse direction . Hence concentration of Hb(CO)4(aq) will be increased .
How are electrons similar and different to the planet Earth?
Answer:
The planets themselves are composed of several trillions or quadrillions or more atoms. As far as hard science is concerned, it would be really hard to picture them as electrons. Conclusion: It can be said with a great accuracy that our planets are NOT huge electrons.
Rutherford's experiments showed that the mass of atoms was mostly concentrated in a very small region, with charge equal to the atomic number- the nucleus. He absolutely did not show, nor is it true, that electrons orbit the nucleus as if they were planets. That was a guess people made in trying to figure out how to picture the atom.
(Hope this helps) Sky
Fiona is examining a material. She notices that the material has a dull appearance and feels very brittle.
Fiona is most likely examining a _______
(I'll give brainliest)
"Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides." - Wikipedia
what happens to the density of a box full of leaves if you crush up all the leaves and place them in another box
A the density increases
B the density stays the same
C the density decreases
D the density first decreases, then increases
Answer:
B the density stays the same
Help me!
what is the biggest disadvantage of using nuclear power to produce electricity?
a. nuclear fission releases more air pollution than burning coal
b. nuclear fission produces less energy than burning coal or oil.
c. nuclear waste must be safely stored for many years
d. nuclear waste must be incinerated
The biggest disadvantage of using nuclear power to produce electricity is the nuclear waste must be safely stored for many years.
What is nuclear power?Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from:
Nuclear fission Nuclear decay and Nuclear fusion reactionsNuclear reactions produces high amount of energy and many waste materials which are non degradable and will stay in the environment for the long time.
Hence, nuclear waste must be safely stored for many years.
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A typical cell phone uses wavelength of 0.36meters. How much energy does this wave have?
Answer:
55×10^-26 J
Explanation:
We can calculate the energy of the wave from
E= hc/λ
Where
h= Planks constant = 6.6×10^-34 Is
c= speed of light = 3×10^8 ms-1
λ= wavelength of the wave = 0.36 metres
Recall that cell phone use radio waves which belong to the electromagnetic spectrum hence it must possess the speed of light.
E= 6.6×10^-34 × 3×10^8/ 0.36
E= 55×10^-26 J
Hence the energy possessed by 0.36 meters wavelength radio waves is 55×10^-26 J
Balance the following equation by adding the correct mole numbers.
P⁴+Cl²->PCl³
Hey there!
P₄ + Cl₂ → PCl₃
First, let's balance Cl.
There are 2 on the left, and 3 on the right.
To balance this, let's put a coefficient of 3 in front of Cl₂ and a coefficient of 2 in front of PCl₃.
P₄ + 3Cl₂ → 2PCl₃
Now we have 6 on the left and 6 on the right.
Next, let's balance P.
There are 4 on the left and 2 on the right.
Let's change the coefficient in front of PCl₃ from 2 to 4.
P₄ + 3Cl₂ → 4PCl₃
There are now 4 P on each side.
However, now Cl is unbalanced, with 6 on the left and 12 on the right.
We can change the coefficient in front of Cl₂ from 3 to 6.
P₄ + 6Cl₂ → 4PCl₃
So now, we have 4 P on each side and 12 C on each side.
This is our final balanced equation.
Hope this helps!
Answer:
1:1
Explanation:
Took test
Which equilibrium describes a reversible reaction a short time after starting the reaction with reactants only?
Answer:
Should be A
Explanation:
