why helium is inactive
Answer:- Outer shell of the He (1s) is completely filled with the 2 electrons He has very low intermolecular forces so it donot get liquefied even Due to complete duplet it has stable configuration so it doesn't required to react with another atoms to attain stabilityDue to high stability it is also placed among noble gases which are also called inert gasesOne of the advantages of nylon over rayon is that nylon:
Explain the process of how James Chadwick
found the neutron.
Answer:
In 1932, the physicist James Chadwick conducted an experiment in which he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium. The resulting radiation showed high penetration through a lead shield, which could not be explained via the particles known at that time.
Explanation:
F. How many centigrams are in 253,000 picograms?
Plz show work
The answer is 2.53e-5, I unfortunately don't know how you would really show the work other than showing the division.
Balance the following chemical equations:
Problem 1
Pb(SO )2 +
Pb(OH), =
H,SO, +
Н,O
Answer:
2+1=1+4
Explanation:
2h2so4+1pb(oh)4=1pb(so)4+4h2o
A sample contains 2.2 g of the radioisotope niobium-91 and 15.4 g of its daughter isotope, zirconium-91.
If the half-life of niobium-91 is 680 years, how long will it take for the decay described in the previous question?
680 years
1,360 years
✓2,040 years (correct answer)
2,720 years
Time to decay : 2040 years
Further explanation
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements ,so that they generally decay, are alpha (α), beta (β) and gamma (γ) particles
General formulas used in decay:
[tex]\tt Nt=No.\dfrac{1}{2}^{\dfrac{T}{t\frac{1}{2} }[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
moles zirconium :
[tex]\tt \dfrac{15.4}{91}=0.169[/tex]
moles niobium :
[tex]\tt \dfrac{2.2}{91}=0.0242[/tex]
the half-life of niobium-91 is 680 years
Reaction
⁹¹₄₁Nb ⇒⁹¹₄₀Zr + ₁⁰e
Amount of Nb from reaction : 0.169
Amount of initial Nb = 0.0242 + 0.169 = 0.1932
Time to decay (T) :
[tex]\tt 0.0242=0.1932.\dfrac{1}{2}^{\dfrac{T}{680}}\\\\0.1252=\dfrac{1}{2}^{\dfrac{T}{680}}\\\\\dfrac{1}{2}^{3}=\dfrac{1}{2}^{\dfrac{T}{680}}\\\\T=680\times 3=2040[/tex]
Answer:
It’s CCCCCCCCCCCCCCC
Explanation:
I just took the instruction and yes its “C.”
PLEASE HELP ASAP The concentration of a solution is equal to the mass of solute divided by the volume of solvent. Units of concentration are grams per 100 milliliters, g/100 mL. You add 12g of sugar to 100 mL of water. What is the concentration?
. 12 g/100mL
12 g/100mL
12g
120g
Answer:
120 g is the answer I think
Bismuth has a density of 9.80 g/cm^3. What is the mass of 3.02 cm^3 bismuth?
Answer:
29.596 g/cm^3
Explanation:
mass=density*volume=9.8*3.02=29.596
Using the formula M1V1 = M2V2 , how many milliliters of a 2. 50 M hydrochloric acid solution is required to make 100. 0 mL of a 0. 750 M solution?.
Dilution of the solution can be calculated by the formula of the molarity and volume. The initial volume of 2.50 M solution was 30 mL.
What is the relationship between molar concentration and dilution?Molar concentration or the dilution factor is in an inverse relationship and with an increase in the dilution, the molarity of the solution decreases.
Given,
Initial molarity = 2.50 M
initial volume = ?
Final molarity = 0.750 M
Final volume = 100.0 ml
Substituting values in the formula:
[tex]\begin{aligned}\rm V_{1} &= \rm \dfrac{M_{2}V_{2}}{M_{1}}\\\\&= \dfrac{0.750 \times 100}{2.50}\\\\&= 30 \;\rm mL\end{aligned}[/tex]
Therefore, 30 mL was the initial volume of the solution before it was diluted.
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quickly, please. If you want to have better frost protection, you can add an excess of 0.0200 moles of salt or 0.0200 moles of sugar. Explain which would result in the greater frost protection – sugar or salt. Justify your response.
The more the number of particles the better the frost protection hence, salt offers a better frost protection than sugar.
What is frost protection?The term frost protection has to do with protection agianst the accumulation of frost or snow.
We have to note that this property depends on the ability of the substance to decrease the melting point of ice. The more the number of particles the better the frost protection hence, salt offers a better frost protection than sugar.
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) The atomic number of magnesium is 12.
Magnesium exists as three isotopes; Magnesium-24, Magnesium-25 and Magnesium 26.
Describe, by reference to the numbers of subatomic particles, the differences between one atom of
each of these isotopes.
(2)
Answer: The difference between these 3 isotopes is the number of neutrons.
The atomic mass of an atom is the number of protons plus neutrons. We know that the atomic number of magnesium is 12, so therefore there are 12 protons.
In Magnesium-24, there are 24-12 neutrons = 12 neutrons.
In Magneusium-25, there are 25-12 neutrons = 13 neutrons
In Magnesium-26, there are 26-12 neutrons = 14 neutrons
please help!!!
A chemist dilutes 2.0 L of a 1.5 M solution with water until the final volume is 6.0 L. What is the new molarity of the solution?
show work.
The new molarity of the solution is 0.5M.
HOW TO CALCULATE MOLARITY?The molarity of a solution can be calculated by using the following expression:
C1V1 = C2V2
Where;
C1 = initial molarityC2 = final molarityV1 = in initial volumeV2 = final volumeAccording to this question, a chemist dilutes 2.0 L of a 1.5 M solution with water until the final volume is 6.0 L.
1.5 × 2 = 6 × C2
3 = 6C2
C2 = 3/6 = 0.5M
Therefore, the new molarity of the solution is 0.5M.
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The mass of the sugar in a small sugar packet is about one gram. If we could harness all of the energy contained in the nuclei of atoms in a small sugar packet, how much energy could we obtain?
Select one:
a. 9.00 x 1013 J
b. 3.00 x 105 J
c. 9.00 x 1010 J
d. 9.00 x 1016 J
Answer:
a. 9.00 x 1013 J
Explanation:
Trust me
PLEASE ANSWER AND I WILL GIVE BRAINLIEST! THE ANSWER IS NOT B
Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below.
A large black cross in a purple circle with a black line around the purple, with 10 small green balls dispersed within the purple circle.
What experimental evidence led to the development of this atomic model from the one before it?
A. A few of the positive particles aimed at a gold foil seemed to bounce back.
B. The colors of light emitted from heated atoms had very specific energies.
C. Equations were used to identify regions around the nucleus where electrons would likely be.
D. Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
A
Explanation:
It says it in the videos my sister watch on Edgenuity. A few of the positive particles aimed at a gold foil seemed to bounce back. If you take notes it says it. (ps. I am not trying to be mean I am just saying- no hurt feelings?)What is the concentration, in grams per liter, of a solution prepared by dissolving 0.00040 mol hcl in 2.2 l h2o? assume that the volume of the solution does not change when the hcl is added. g/l
The concentration, in grams per liter, of a solution prepared by dissolving 0.00040 mol HCl in 2.2L H₂O is 0.0066 g/L.
How we calculate mass from moles?Mass of any substance will be calculated by using their moles as:
n = W/M, where
W = required mass
M = molar mass
GIven moles of HCl = 0.00040 mole
Mass of 0.00040 mole of HCl will be calculated as:
W = (0.00040mol)(36.45g/mol) = 0.01458g
Given volume of Water = 2.2 L
Now the concentration in molality (g/L) will be calculated as:
concentration = (0.01458g) / (2.2L) = 0.0066 g/L.
Hence required concentration is 0.0066 g/L.
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Answer: first one is 0.0066 and second one is 6.6
Explanation:
I got it right
Small quantities of hydrogen and helium gas at the same temperature are released simultaneously at one end of a laboratory. State with reason which gas is more likely to be detected at the other end.
Answer:
hydrogen
Explanation:
it diffuses faster compared to helium since it is less dense
Answer:
Hydrogen
Explanation:
It is lighter than helium
2. Box A and box B have the same mass. Box A,
however, has more volume. Which box has
less density? Why?
The more matter you place into a defined
volume, the denser it becomes. Therefore they have the same density because (Mass is the amount of matter in a object)
What mass of sugar C12H22O11 is required to provide 2.50 x 1023 molecules of O2?
an unknown gas at constant temperature, has a pressure of 2 atm and a volume of 7 L. Calculate the final pressure if the volume drops to 0.7 L.
At constant temperature, if the volume of the unknown gas drops to the given value, the pressure increases to 20.0atm.
Given the data in the question;
Initial volume of the unknown gas; [tex]V_1 = 7L[/tex]Initial pressure of the unknown gas; [tex]P_1 = 2atm[/tex]Final volume of the unknown gas; [tex]V_ 2 = 0.7L[/tex]Final pressure of the unknown gas; [tex]P_2 = \ ?[/tex]
Boyle's lawBoyle's law simply states that the volume V of any given quantity of gas is inversely proportional to its pressure P as long as temperature remains constant.
Boyle's law is expressed as;
[tex]P_1V_1 = P_2V_2[/tex]
Where [tex]P_1[/tex] is Initial Pressure, [tex]V_1[/tex] Initial volume, [tex]P_2[/tex] is Final Pressure and [tex]V_2[/tex] is Final volume.
We substitute our given values into the expression above to determine the final pressure.
[tex]P_1V_1 = P_2V_2\\\\P_2 = \frac{P_1*V_1}{V_2} \\\\P_2 = \frac{2atm\ * 7L}{0.7L} \\\\P_2 = \frac{2atm\ * 7}{0.7}\\\\P_2 = \frac{14atm}{0.7}\\\\P_2 = 20.0atm[/tex]
Therefore, at constant temperature, if the volume of the unknown gas drops to the given value, the pressure increases to 20.0atm.
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Of all the planets in our solar system, which planet, overall, is the MOST like Earth?
A. Mercury
B. Venus
C. Mars
D. Uranus
Answer:
The answer is Venus. So B
A board measures 68 inches. How many feet is this?
Answer:
5.66667
Explanation: because you have to take 12 and see how many times it fits into 68. Hope this helps! :^)
The standard reduction potentials for two half-cells involving iron are: given below. Fe2+ (aq) + 2e– ® Fe (s) Eο = –0.44 V Fe3+ (aq) + e– ® Fe2+ (aq) Eο = +0.77 V What is the equation and the cell potential for the spontaneous reaction that occurs when the two half-cells are connected?
Answer:
Explanation:
Fe⁺² (aq) + 2e⁻ = Fe (s) ; E⁰ = - .44 V
Fe⁺³ (aq) + e⁻ = ® Fe²⁺ (aq) ; E⁰ = + .77 V
Reduction potential of second reaction is more , so it will take place , ie Fe⁺³ will be reduced and Fe will be oxidised .
So reaction in the combined cell will be
2Fe⁺³ + Fe = 3Fe⁺²
cell potential = .77 - ( - .44 )
= 1.21 V .
Decide if these characteristics belong to the Protons, neutrons or Electrons.
1) They spin around the nucleus. _____
2) They are located in the orbits. _____
Answer:
1)electrons
2)protons, neutrons
Explanation:
please mark me as brainlest
Answer:
1 . c
2. a , b
Explanation:
1 . the electrons spin around the nucleus of an atom
2. the protons and neutrons are located in the orbit of an atom
Definition: This is a property of matter that can be identified without changing the identity of the substance.
Answer:
physical property
Explanation:
A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?
V
Na
Mg
Se
its Na
A substance has a density of 6.26 g mL-1. What is the volume that a 2.49 g sample would occupy?
Answer:
The answer is 0.4 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 2.49 g
density = 6.26 g mL-1
So we have
[tex]volume = \frac{2.49}{6.26} \\ = 0.397763578...[/tex]
We have the final answer as
0.4 mLHope this helps you
60 points please help me i would appreciate it!
Answer:
[tex]\huge\boxed{\sf 39\ L}[/tex]
Explanation:
In the reaction:
for 1 mol of propane, 3 moles of CO₂ are produced.
Volume of propane = 13 L
At STP,
1 mol of propane = 22.4 L/dm³ molar value
So,
Moles in 13 L of propane:
= volume / molar volume
= 13 / 22.4
= 0.58 mol
Since,
1 mol of propane = 3 moles of CO₂
0.58 mol of propane = 3 × 0.58 mol of CO₂
0.58 mol of propane = 1.74 mol of CO₂
Converting 1.74 mol of CO₂ into L:
[Multiply it by 22.4 L/mol]
= 1.74 mol × 22.4 L/mol
= 39 L
[tex]\rule[225]{225}{2}[/tex]
What is the Energy of a wave whose frequency is 8.45 x 10^14 Hz?
What is the wavelength of a wave whose frequency is 8.25 x 10^14 mHz? (1mHz is 10-3 Hz)
What is the frequency of a wave whose wavelength is 4.10 x 10^-7 nm? (1nm is 10-9 m)
What is the wavelength of a wave whose energy is 5.50 x 10^-7 mJ (1 mm = 10^-3 m)
Answer:
E = hf
E = hc/lamda
where E-energy,
h-planck's constant (6.62 x 10^-34 Js)
f- frequency ( f = c/lamda)
c-velocity of light ( 3 x 10^8 m/s)
lamda- wavelength
you can this formula to solve all the 4 questions.
Liquids have a density greater than 1 g/m?
Sometimes true? True? never true?
Answer:
Water has a density of 1 g/m so it could be sometimes true
Explanation:
Answer:True
Explanation: If you look it up it says the anwser. Can you give me a thank and a five.
Also very important if you put your question in the search bar and put quizlet after then you can find answer for you test quizes and more.
I hope this helps you and have a great day bye.
Which of the following is an ozone depleting substance (ODS)?
a.
ultraviolet radiation
b.
chlorofluorocarbon (CFC)
c.
biogeochemical cycle
d.
none of the above
Answer:
b
Explanation:
In an ecosystem, the ozone depleting substance is chlorofluorocarbon or the CFC's.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the ecosystem through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.There are different types of ecosystems.
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Which is the electron configuration for bromine?
Answer:
bromine atomic number =35
1s²2s²2p^6 3s² 3p^6 4s² 3d^10 4p^5.