The ⁴⁰₁₈X is the symbol for ⁴⁰₁₈Ar - atom and it has 18 protons, 18 electrons, and 22 neutrons.
What is Mass number ?Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.
In the given element, ⁴⁰₁₈X, Subscript 18 is the number of proton and is also equal to the number of electron. While supercript 40 is the atomic mass.
The number of neutrons is given by subtracting the proton number from the mass number.
Therefore,
Number of Neutron = Mass Number - Atomic Number
= 40 - 18
= 22 Neutrons
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Which is the best One to One tutoring website?
Answer:
Brainly or Chegg tutors.
Explanation:
Try those!
Explain why the compound Cl2O has a low melting and boiling point.
what are the condition for a gas like carbon (II) oxide to obey the gas laws?
Answer:
I don't know the answer, but I can give options :)
Explanation:
A gas such as carbon monoxide would be most likely to obey the ideal gas law at:
Option 1) High temperatures and low pressure.
Option 2) Low temperatures and high pressure.
Option 3) High temperatures and high pressure.
Option 4) Low temperatures and low pressure.
Answer:
The gas must occupy 0 volume at -273°celcius
What is open system?
What is close system?
What is the valency of an atom?
State Heisenberg uncertainty principle
Define endothermic reaction
Answer:
1) open system is the system through which both matter and energy and enter as well as leave
ex - open beaker
2) close system is the system through which only energy can leave but matter cannot
ex - pressure cooker.. ( energy leave as air)
3) Valency of an atom is the no. of outer most electron which can participate in a reaction.
4). Heisenberg uncertainty principal states that it is impossible to measure or calculate exactly, both the position and the momentum of an object
5) The reaction in which heat is required to make products are called endothermic reaction. it cools down the surrounding .
Which are the product(s) of this chemical reaction? FeCl 3 + 3NH 4OH ->
a. 3NH4Fe + Cl3OH
b. 3FeCl3NH4OH
c. 3NH4Cl + 3FeOH
d. Fe(OH)3 + 3NH4Cl
6a. 0.898 mol sample of hydrogen gas at a temperature of 20.0 °C is found to occupy a volume of 24.5 liters. The pressure of this gas sample is
mm Hg.
6b. A sample of helium gas collected at a pressure of 991 mm Hg and a temperature of 300 K has a mass of 2.82 grams. The volume of the sample is
L.
8a. What volume is occupied by a 0.814 mol sample of xenon gas at a temperature of 0 °C and a pressure of 1 atm?
8b. A 1.21 mol sample of oxygen gas occupies a volume of
L at STP.
9b.What volume of carbon dioxide is produced when 7.95 liters of butane (C4H10) react according to the following reaction? (All gases are at the same temperature and pressure.)
butane (C4H10)(g) + oxygen(g) carbon dioxide(g) + water(g)
liters carbon dioxide
10b. What volume of carbon dioxide is produced when 0.504 mol of calcium carbonate reacts completely according to the following reaction at 0°C and 1 atm?
calcium carbonate ( s ) calcium oxide ( s ) + carbon dioxide ( g )
liters carbon dioxide
Gas law refers to the relationship between the temperature, volume and pressure of a gas.
What is gas laws?The term gas law refers to the relationship between the temperature, volume and pressure of a gas.
6a) PV =nRT
P = nRT/V
P = 0.898 * 0.082 * 293/24.5
P = 0.88 atm
6b) Number of moles of helium = 2.82 g/4 g/mol = 0.705 moles
Pressure = 991 mm Hg or 1.3 atm
V = nRT/P
V = 0.705 * 0.082 * 300/1.3
V = 13.3 L
8a) V = nRT/P
V = 0.814 * 0.082 * 273/1
V = 18.22 L
8b) 1 mole of oxygen occupies 22.4 L
1.21 mole of oxygen occupies 1.21 mole * 22.4 L/ 1 mole
= 27.1 l
9b) C4H10(g) + 13/2O2 -----> 4CO2 + 5H20
1 moles of butane produces 4 moles of CO2, It then follows that the volume of carbon dioxide produced is 4( 7.95 liters) = 31.8 litres
10b) CaCO3 ------> CO2 + CaO
Since the reaction is 1:1, 0.504 mol of CO2 is produced
PV =nRT
V = 0.504 * 0.082 * 273/1 atm
V = 11.3 L
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In an experiment, a student gently heated a hydrated copper compound to remove the water of hydration. The following data was recorded:
Mass of crucible, cover, and contents before heating = 23.4 g.
Mass of empty crucible and cover = 18.82 g.
Mass of crucible, cover, and contents after heating to constant mass = 20.94 g.
The percent of water in the hydrated salt will be 55.08 %
What is mass?Mass is a numerical measure of quantity, which is a basic feature of all matter. The kilogram is the international system of units of mass.
Given data;
Mass of crucible, cover, and contents before heating = 23.4 g.
Mass of empty crucible and cover = 18.82 g.
Mass of crucible, cover, and contents after heating to constant mass = 20.94 g.
⇒Mass of hydrated salt used = Mass of the crucible, cover, and contents before heating - Mass of the empty crucible and cover
⇒Mass of hydrated salt used = = 23.54 g – 18.82 g
⇒Mass of hydrated salt used = = 4.72 g
⇒Mass of dehydrated salt after heating = Mass of the crucible, cover, and contents after heating to constant mass-Mass of the empty crucible and cover
⇒Mass of dehydrated salt after heating = 20.94 g – 18.82 g
⇒Mass of dehydrated salt after heating = 2.12 g
⇒ Mass of water liberated from salt = Mass of hydrated salt used - Mass of dehydrated salt after heating
⇒ Mass of water liberated from salt = 4.72 g – 2.12 g
⇒ Mass of water liberated from salt = 2.60 g
Water % in the hydrated salt is found as;
% water =(mass of water/ mass of hydrated salt)× 100
% water =(2.60/4.72) × 100
% water =55.08 %
Hence the percent of water in the hydrated salt will be 55.08 %
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What is the rule when "ao" or "oo" are together when naming covalent bonds
They are converted into a single “o” when "ao" or "oo" are together when naming covalent bonds.
What is a covalent bond?A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.
Sometimes, while naming the chemical compounds, a problem arises when compounds with “ao” and “oo” are written with -ide name. Conventionally, they are converted into a single “o”.
For example, the “ao” in the dichlorine hept-ao-xide ([tex]Cl_2O_7[/tex]). This “ao” in the [tex]Cl_2O_7[/tex] can be converted into “o”. As the result, the correct name of this compound would be dichlorine hept-o-xide.
Hence, they are converted into a single “o” when "ao" or "oo" are together when naming covalent bonds.
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A 1dm3 solution was made by mixing 0.0040 mol of HCl(aq) and 0.0025 mol of NaOH(aq). What was the pH of the resulting solution?
The pH of the resulting solution is 2.82.
What is pH ?pH is the measure of acidity and alkalinity of a solution , It has a range of 1 to 14.
HCl + NaOH → NaCl + H₂O
0.0040 .0025 0 0
0.0040 -0.0025 0 0.0025 0.0025
Moles of HCl = 0.0015
As 0.0025 moles of NaOH reacts with 0.0025 moles of HCl leaving behind 0.0015 moles of HCl
Concentration of HCl = 0.0015/ 1 = 0.0015 M
[ H⁺] = 0.0015 M
pH = -log [ H⁺]
pH = -log [ 0.0015]
pH = 2.82
Therefore the pH of the resulting solution is 2.82.
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Activity 1.3 Put an unlit incense stick in a corner of your class. How close do you have to go near it so as to get its smell? Now light the incense stick. What happens? Do you get the smell sitting at a distance? Record your observations.
Please help thanks in advance
Calculate the equilibrium constant K for the following reaction at 25°C from standard electrode potentials. Fe³(aq) + Cu(s) = Fe²(aq) + Cu²(aq)
The equation is not balanced. Use standard reduction electrode potentials.
The equilibrium constant K for the following reaction at 25°C from standard electrode potentials is Antilog (37.5).
What is chemical equilibrium?Chemical equilibrium is the condition in the course of a reversible chemical reaction in which no net change in the amounts of reactants and products occurs.
Reduction Half-Reaction
[tex]Fe^{3+}[/tex](aq)+[tex]e^-[/tex] →[tex]Fe^{2+}[/tex](aq)
Standard reduction electrode potentials = +0.77
Oxidation Half-Reaction
Cu(s) = [tex]Cu^{+2}[/tex](aq) + 2[tex]e^-[/tex]
Standard reduction electrode potentials = -0.34
E° cell= E°cathode- E°anode
E° cell= +0.77+0.34
E° cell=1.11
E°cell= 0.0592÷n logK
From the redox reaction equations above, n=2
1.11 V= 0.0592÷2 logK
37.5 = logK
K= Antilog (37.5)
Hence, the equilibrium constant K for the following reaction at 25°C from standard electrode potentials is Antilog (37.5).
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water boils at 100 degrees celsius at sea level. If the water in this experiment did not boil to 100 degrees celsius, what could the reason be?
Answer:
It depends on how high you are above sea level
Explanation:
I did an experiment in my Scince class that showed, the less air that is around water will lessen it’s boiling level. We put water in a glass beaker inside of our vacuum chamber, we made a vacuum in he chamber. Making a vacuum is like being on a mountain, the less air the lower the boiling point. The water then began to boil due to the water evaporating. When we reached to maximum vacuum that we could the water started to boil at 61°C. No the water was not very hot, it was just warm water that just so happened to also be boiling, cool right!!! Anyways, we played with dry ice the next day.
Hoped this helped.
Hope I earned your star rating or helpful rating from this.
the air pressure around the experiment is lower than at sea level
What is the frequency of the green light emitted by a hydrogen atom with a wavelength of 525 nm?
The frequency of the green light emitted by a hydrogen atom with a wavelength of 525 nm is [tex]5.71[/tex]×[tex]10^{14} s^{-1}[/tex]
What is wavelength?
It is the length between two successive crests or troughs of any wave.What is a frequency?
It is the total number of waves that pass through a fixed point in unit time.Wavelength=525nm
The relation between wavelength and frequency
[tex]v=\frac{c}{lambda}[/tex]
[tex]v=[/tex]frequency
[tex]c=[/tex]speed of light = [tex]3.0[/tex]×[tex]10^{8}[/tex][tex]m/sec[/tex]
λ(lambda)=wavelength
substitute the value in the equation mentioned above
[tex]v=3.0[/tex]×[tex]10^{8}[/tex][tex]/525[/tex]×[tex]10^{-9}[/tex]
[tex]=5.71[/tex]×[tex]10^{14}[/tex][tex]s^{-1}[/tex]
hence, the frequency of the green light emitted by a hydrogen atom with a wavelength of 525 nm is [tex]5.71[/tex]×[tex]10^{14} s^{-1}[/tex]
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Determine the hybrid orbital of this molecule.
The hybrid orbital of this molecule is [tex]sp^3[/tex]. Hence, option C is correct.
What is hybridisation?Hybridization is defined as the concept of mixing two atomic orbitals to give rise to a new type of hybridized orbitals.
In this compound, [tex]sp^3[/tex] a hybrid orbital makes I-O bonds. Due to [tex]sp^3[/tex]hybridization iodate should have tetrahedral geometry but because of the presence of lone pair of electrons the shape of [tex]IO^{3-}[/tex] the ion is pyramidal.
The hybrid orbital of this molecule is [tex]sp^3[/tex]. Hence, option C is correct.
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If 13.0 g of MgSO4⋅7H2O is thoroughly heated, what mass of anhydrous magnesium sulfate will remain?
6.349 g mass of anhydrous magnesium sulfate will remain.
What are moles?A mole is defined as 6.02214076 × 1023 of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Molar mass MgSO₄.7 H₂O = 246.52 g/mol
[tex]Moles =\frac{mass}{molar \;mass}[/tex]
[tex]Moles =\frac{13.0 g}{246.52}[/tex]
0.0527 moles
Molar mass MgSO₄ = 120.4 g/mol
Mass of anhydrous magnesium sulfate :
( 0.0527 x 120.4 ) => 6.349 g
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Under which conditions will gases best dissolve in liquids?
A. when the pressure is low and the temperature is low
B. when the pressure is high and the temperature is high
C. when the pressure is low and the temperature is high
D. when the pressure is high and the temperature is low
c option is correct answer
What hazard symbol does Pesticides have?
The hazard symbol that pesticides have are skull and cross bones.
What are hazard symbols?Hazard symbols represent those symbols that are used as a warning sign towards materials that are dangerous to health.
Example of symbols used are:
Exploding bomb symbol: used for explosivesFlame symbol: used for flammablesskull with cross bones symbol: used for toxic substances such as pesticides.Therefore, the hazard symbol that pesticides have are skull and cross bones.
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The hazard symbol of pesticides is a picture of the skull and crossbones.
What are pesticides?Pesticides are known as substances that are meant to control or destroy pests. They include herbicide, insecticide, nematicide, avicide, rodenticide, bactericide, insect repellent, etc.
The hazard symbol of pesticides is a picture of the skull and crossbones
Thus, the hazard symbol of pesticides is a picture of the skull and crossbones.
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what kind of investigations allow for the control of variables?
The experimental investigations allow for the control of variables.
What is control of variables?The control of variables is the experimental element that remains constant and unchanged throughout the experiment of the investigation.
The control of variables is held constant during the experiment to test the relation between the dependent and independent variables.
Thus, An experimental investigation allows the control of variables all the time.
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Refer to the following table of Ksp values to answer the question below.
Compound
PbS
SnS
ZnS
HgS
Ksp
3 x 10-29
1 x 10-26
2x 10-25
1.6 x 10-52
A solution has 0.01 M Pb²+, 0.01 M Sn²+, 0.01 M Zn²+, and 0.01 M Hg2+. As tiny amounts of sulfide ion are slowly added
to the solution, which compound will precipitate first?
PbS
O Fes
HgS
SnS
HgS will precipitate first when tiny amounts of sulfide ion are slowly added to the solution.
What is Ksp?The solubility product constant, Ksp, is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution.
If Solubility product is greater than the ionic product then no precipitate will form on adding more solute because unsaturated solution is formed.
If Solubility product is lower than the ionic product then excess solute will precipitate out because of the formation of super saturated solution.
Here, Ksp value of HgS is very low. Hence, HgS will precipitate first when tiny amounts of sulfide ion are slowly added to the solution.
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An imaginary element, Y, has two different isotopes.
y has a percentage abundance of 25% and 29y has a percentage abundance of
75%.
Which of the following is the relative atomic mass of Y?
26
25
27
28
Answer:
kliujhygfdsalikumjyhbtgvf
Explanation:
The answer is:
28
I just got this answer so I don't know how to work it out but i hope it helps.
How many molecules in HNO3?
An unknown gas effuses at a rate of 2.0 times the rate of Cl₂. What is the molar mass of the unknown gas?
The molar mass of the unknown gas is determined as 17.75 g.
Rate of gas diffusionThe rate of gas diffusion is given by Graham's law.
R₁√M₁ = R₂√M₂
where;
R₁ is the rate of diffusion of the unknown gasM₁ is the molecular mass of the unknown gasR₂ is rate of diffusion of chlorine gasM₂ is the molecular mass of chlorine gas[tex]\frac{R_1}{R_2} = \sqrt{\frac{M_2}{M_1} } \\\\\frac{2R_2}{R_2} = \sqrt{\frac{71}{M_1} }\\\\2 = \sqrt{\frac{71}{M_1} }\\\\2^2 = \frac{71}{M_1} \\\\M_1 = \frac{71}{4} \\\\M_1 = 17.75 \ g[/tex]
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Describe the subatomic structure of the nucleus, including the structure of each nucleon. Draw a picture. Describe the forces that hold the nucleus together and draw them on your diagram. Explain how beta emission works.
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How many significant figures does 7,874.9640 s have?
Submit Question
Answer:
8 significant figures
Explanation:
All numbers (that are not zero) are always significant. Because there is a zero at the end of the number after the decimal place, this makes this zero also significant. This zero is significant because it makes the number more precise. Therefore, all of the numbers in this number are significant.
Answer:
There are 8 sig figs
Explanation:
A temperature of 300 Kelvin is how many degrees Celsius?
A. 273
B. 27
C. 573
D. 300
Answer:
The answer is B, to convert kelvin to temperature you :
Subtract 273 (k - 273)
Determine the hybrid orbital of this molecule.
There are three sigma bonds, so hybridization of the molecule will be sp²
When did China's earliest civilization originate?
Answer:
The Chinese civilization really has an exact chronology, and the historical period began in the first year of the Western Zhou Dynasty in 841 BC. Before that, only the lineage records of the kings were recorded. Therefore, the earliest origin of Chinese civilization has not yet been finalized. Although there are many records about the Xia Dynasty in the traditional literature, due to the late completion of the book, there is no recognized evidence of the existence of the Xia Dynasty and its previous history. Therefore, some people in the modern and modern historical circles have always questioned the existence of the Xia Dynasty. sex.
Explanation:
In a container with 512.1 L water, the pH should be changed to 5 using 95% sulfuric acid. The question is how much sulfuric acid is needed.
Answer:
15
Explanation:
I got it right I just had the answer
uses of radio isotopes
Answer:
1. Used in many smoke detectors for homes and businesses to measure levels of toxic lead in dried paint sample to ensure uniform thickness in rolling processes like steel and paper production and to help determine where oil wells should be drilled.
2.Used to treat cancerous tumors to measure correct patient dosages of radioactive pharmaceutical to measure and control the liquid flow in oil pipelines to tell researchers whether oil wells are plugged by sand and to ensure the right fill level for packages of food, drugs, and other
products.
3.Used in medical diagnosis
4.Used to treat thyroid disorders. (Graves’s disease).
5.Used in molecular biology and genetics research.
6.Used in nuclear medicine for lung ventilation and blood flow studies.
7.Used in dental fixtures like crowns and dentures to provide a Uranium-234 natural color and brightness.
8.Used in electric blanket thermostats and to gauge the thickness of thin plastics, thin sheet metal, rubber, textile and paper.
What is the osmotic pressure, in atm, of a 0.287 M solution of MgCl2 at
37.0 °C? (assume complete dissociation).
Answer:
Π = 21.9 atm
Explanation:
The equation used to find osmotic pressure is:
Π = iMRT
In this formula,
>> Π = osmotic pressure (atm)
>> i = van't Hoff factor
>> M = molarity (M)
>> R = constant (0.0821 atm*L/mol*K)
>> T = temperature (K)
Remember, van't Hoff factor is the amount of ions the species (MgCl₂) dissociates into while in solution. MgCl₂ dissociates into 3 ions. These ions are Mg²⁺ and 2 Cl⁻.
The temperature needs to be in Kelvin....
37.0 °C + 273.15 = 310.15 K
You now know the value of all the variables.
Π = iMRT
Π = (3)(0.287 M)(0.0821 atm*L/mol*K)(310.15 K)
Π = 21.9 atm
