Answer:
2 Al and 3 S
Explanation:
Al2S3 so 2 Al and 3 S
Assuming the substance is one of those listed in the table presented in this lesson, what is the identity of the substance?
iron
copper
lead
aluminum
Answer: Iron
Explanation: IRON : Iron is an element with symbol Fe and atomic number 26 2) it is the fourth most common element in earth's crust 3) It is a heavy silvery grey metal belongs to the first transition series. 4) High ductility and malleability 5) It is a good conductor.
The identity of the substance is Iron.
Properties of IronChemical propertiesThe element iron has the atomic number 26 and the symbol FeElectronic configuration of Fe is [AR] 3d6 4s2The atomic weight of Iron is 55.847The element iron belong to the group VIII of the periodic tableIt is the fourth most prevalent element in the crust of the worldIt is a highly reactive element as it gets rusted readily in the moisture of airPhysical propertiesIt is a heavy metal in the first transition series The color of iron is silvery greyHigh malleability and ductilityIt has a strong electrical conductivity.Learn more about periodic table on
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The energy required for the hypothetical reaction
2A+B⇌2C+2D
is 309 kJ as written.
How much heat is absorbed when 2.60 mol of A reacts?
Express your answer to three significant figures and include the appropriate unit.
Answer:
402 kJ
Explanation:
Because the energy of the reaction is positive, the reaction is endothermic. This means energy is a reactant.
You can determine how much energy/heat is absorbed using the balanced chemical equation. You can convert the moles A using the ratio composed of the coefficient in front of A and the energy required for each reaction.
2A + B + 309 kJ ⇌ 2C + 2D
2.60 moles A 309 kJ
---------------------- x -------------------- = 402 kJ
2 moles A
Suppose you need to prepare 136.9 mL of a 0.315 M aqueous solution of NaCl.
What mass, in grams, of NaCl do you need to use to make the solution?
Answer:
2.52 g NaCl
Explanation:
(Step 1)
To find the mass, you first need to find the moles NaCl. This value can be found using the molarity ratio:
Molarity = moles / volume (L)
After you convert mL to L, you can plug the given values into the equation and simplify to find moles.
136.9 mL / 1,000 = 0.1369 L
Molarity = moles / volume
0.315 M = moles / 0.1369 L
0.0431 = moles
(Step 2)
Now, you can use the molar mass to convert moles to grams.
Molar Mass (NaCl): 22.990 g/mol + 35.453 g/mol
Molar Mass (NaCl): 58.443 g/mol
0.0431 moles NaCl 58.443 g
------------------------------ x ------------------- = 2.52 g NaCl
1 mole
What is the frequency of
an electron with a wavelength
of 225 nm?
Answer:
1.33 x 10¹⁵ Hz
Explanation:
You can find the frequency using the following equation:
f = c / λ
In this equation,
-----> f = frequency (Hz)
-----> c = speed of light (3.0 x 10⁸ m/s)
-----> λ = wavelength (m)
Before we can plug the values into the equation, we need to convert the wavelength from nm to m.
225 nm 1 m
---------------- x -------------------- = 2.25 x 10⁻⁷ m
1 x 10⁹ nm
f = c / λ
f = (3.0 x 10⁸ m/s) / (2.25 x 10⁻⁷ m)
f = 1.33 x 10¹⁵ Hz
The frequency of a wave can be calculated using the wavelength and and speed of light. The frequency of a wave with 225 nm is 1.33 × 10¹⁵ Hz.
What is frequency ?Frequency of a wave is the number of wave cycles per second. It mathematically taken as the inverse of time taken to travel and it have a unit of s⁻¹ other than Hz.
The wavelength of an electromagnetic wave is the distance between two consecutive crests or troughs.Wavelength and frequency are in inverse relationship. For a longer wavelength the frequency will be lower.
Higher frequency waves are more energetic than longer wavelengths. Thus energy and frequency are in direct proportion
It is given that the wavelength of the electron is 225 nm. Consider the electron behaving as wave and the frequency v can be calculated using the speed of light c as follows:
[tex]v = C/\lambda[/tex]
= (3 ×10⁸ m/s) /(225 ×⁻⁹ m)
= 1.33 × 10¹⁵ Hz.
Hence, the frequency of an electron with a wavelength of 225 nm is 1.33 × 10¹⁵ Hz.
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round off each of the following numbers to two significant figure 0.436 and 9.000
Answer:
0.436 ⇒ 0.44
9.000 ⇒ 9.0
Concept:
Significant figures are where each of the digits of a number are used to express it to the required degree of accuracy, starting from the first nonzero digit.
Therefore, in the context of this question, two significant figure means that two digits of numbers are kept, from left to right, starting from the first nonzero digit.
Solve:
PART I: Rounding 0.4360.436 has 3 significant digits in total starting from left to right
Thus, the last digit should be rounded up / down
Since the last digit is 6, it is greater than 5, so it should be rounded up.
Therefore, a rounded 0.436 is [tex]\Large\boxed{0.44}[/tex]
PART II: Rounding 9.0009.000 has 4 significant digits in total starting from left to right
Thus, the last two digits should be rounded up / down
Since the last two digits are 0, it is less than 5, so it should be rounded up (or remained).
Therefore, a rounded 9.000 is [tex]\Large\boxed{9.0}[/tex]
Hope this helps!! :)
Please let me know if you have any questions
perform the following operation and express the answer in scientific notation 9.80x10^-3 + 1.60 x 10^-4
answer = 9.96x10^-3
I hope that help you
At a certain temperature the reaction
CO2(g) + H2(g) ↔ CO(g) + H2O(g) has Kc = 2.50.
If 2.00 mol of carbon dioxide and 1.5 mol of hydrogen are placed in a 5.00 L vessel and equilibrium is established, what will be the concentration of carbon monoxide?
The concentration of carbon monoxide at equilibrium is 0.209 M.
Concentration of each gasCO2 = 2 mol/5 L = 0.4
H2 = 1.5 mol/5L = 0.3
ICE tableCreate ICE table as shown below
CO2(g) + H2(g) ↔ CO(g) + H2O(g)
I 0.4 0.3 0 0
C - x - x x x
E 0.4 - x 0.3 - x x x
Kc = [CO][H₂O] / [CO₂][H₂]
2.5 = (x²)/(0.4 - x)(0.3 - x)
x² = 2.5(0.4 - x)(0.3 - x)
x² = 2.5(0.12 - 0.7x + x²)
x² = 0.3 - 1.75x + 2.5x²
0 = 1.5x² - 1.75x + 0.3
solve the quadratic equation using formula method;
x = 0.209
Thus, the concentration of carbon monoxide at equilibrium is 0.209 M.
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7. What is the name of an element with 3 protons and 5 neutrons?
Answer: Lithium - 8
Answer:
Lithium-8
Explanation:
The atom with three protons and five neutrons that has a mass number of eight is known as lithium-8.
↬ [tex]what \: is \: psi \:?[/tex]
[tex] \large \underline{ \boxed{ \tt \red{Pounds \: per \: square \: inch}}}[/tex]
[tex] \: \: \: [/tex]
( PSI ) is a measurement of pressure in the Imperial system of measurement.
PSI is commonly used to measure the pressure of gasses (pneumatic pressure) or liquids (hydraulic pressure). PSI is also used as a measure of tensile strength, defined as resistance to pulling forces, and elastic modulus strength, defined as resistance to deformation, which controls the stiffness of materials.[tex] \: \: \: [/tex]
hope helps ~
The equilibrium constant for the following equation:
PCl5(g) <--> PCl3(g) + Cl2(g) is 1.05 at 250 degrees Celsius. If the equilibrium partial pressures of PCl5 and PCl3 are 0.875 atm and 0.463 atm respectively, what is the equilibrium partial pressure of Cl2?
Group of answer choices
A. 1.05 atm
B. 1.98 atm
C. 0.463 atm
D. 0.054 atm
From the calculation, the partial pressure of Cl2 is 1.98 atm. Option B
What is the equilibrium constant?The term equilibrium constant refers to the value that shows us the extent to which reactants are converted into products. We know that the equilibrium constant can only be obtained by the use of the equilibrium partial pressures of each of the species.
Thus we have;
K = p PCl3 . pCl2/pPCl5
p PCl3 = partial pressure of PCl3
pCl2 = partial pressure of Cl2
pPCl5 = partial pressure of PCl5
K = equilibrium constant
Substituting values;
1.05 = 0.463 * pCl2/0.875
pCl2 = 1.05 * 0.875/0.463
pCl2 = 1.98 atm
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Which element belongs to the p6-block of the periodic table?
Oalkaline earth metals
Ohalogens
alkali metals
Onoble gases
Question 5 (Essay Worth 5 points)
(03.01 MC)
TOOIS
The electron configuration of an element is 1s²2s²2p63s¹. Describe what most likely happens when an atom of this element comes near an atom having seven valence electrons.
The likely thing which will occur when an atom of this element 1s²2s²2p6 3s¹ comes near an atom having seven valence electrons is what is referred to as electrovalent bonding.
What is Electrovalent bonding?
This is also referred to as ionic bonding and involves the transfer of atoms from one element to another. This is done so as to ensure that an octet configuration is achieved.
The element 1s²2s²2p6 3s¹ is Sodium and will undergo ionic bonding with the chlorine. One valence electron is transferred from the sodium to the chlorine which makes them stable.
This is therefore the reason why electrovalent bonding will most likely between the two elements.
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If an electron falls from the n = 2 to the n = 1 energy levels in a Hydrogen atom what wavelength of light is emitted?
Group of answer choices
A. 122 nm
B. 1024 nm
C. 97 nm
D. 103 nm
The wavelength is obtained as 122 nm. Option A
What is the wavelength?We know that from the Bohr model of the atom, an electron can move from a higher energy level to a lower energy level or from a lower energy level to a higher energy level. This is the idea of energy quantization as put forward by Neill Bohr.
The wavelength can be obtained by the use of the formula;
1/λ = RH(1/n^2initial - 1/n^2 final)
λ = wavelength of the emitted light
RH = Rydberg's constant
n intial = initial energy level
nfinal = final energy level
Thus;
1/λ = 1.09 * 10^7(1/1^2 - 1/2^2)
1/λ = 1.09 * 10^7( 1 - 0.25)
λ = 122 nm
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What is the [OH-] if the [H3O+] is 1 x 10 -10?
The answer is [OH⁻] = 1 x 10⁻⁴.
[OH⁻] = H₂O ÷ [H₃O⁺]
[OH⁻] = 1 x 10⁻¹⁴ / 1 x 10⁻¹⁰
[OH⁻] = 10⁻⁴
What would you need to do to calculate the molality of 0.2 kg of NaCl in 3 kg
of water?
A. Convert the 3 kg of water to moles of water.
B. Convert the 3 kg of water to liters of water.
C. Convert the 0.2 kg of NaCl to grams of NaCl.
D. Convert the 0.2 kg of NaCl to moles of NaCl
Answer:
D. Convert the 0.2 kg of NaCl to moles of NaCl
Explanation:
The molality equation looks like this:
Molality = moles of solute / mass (kg) of solvent
In this case, the solute is NaCl and the solution is water. So, if you have been given NaCl in kg, you need to convert it to grams and then to moles in order to plug it into the equation.
A student who prefers to study by converting lecture or written information into pictures, graphs, or charts, and then back into words
again: repeating the process as needed and watching videos most likely prefers which learning style?
O a. Visual
O b. Auditory
O c. Reading Writing
O d. Kinesthetic
The answer is C which is Reading Writing
A student who prefers to study by converting lecture or written information. The learning style of the student is reading writing. Thus option c is correct.
What is learning style?Learning style is defined as the hypothesis that learners can be classified based on how they process information.
It can also be defined as a set of theories aimed at explaining variances in individual learning.
There are basically seven types of learning style.
Visual learning style Kinesthetic learning styleAural learning styleSocial learning styleSolitary learning styleVerbal learning styleLogical learning styleReading and writing is one of the best style of learning as by this we can memorize the things for very long time.
Thus, the learning style of the student is reading writing. Thus option c is correct.
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How many mL of a 0.193 M aqueous solution of ammonium bromide, , must be taken to obtain 8.42 grams of the salt?
Answer:
445 mL NH₄Br
Explanation:
(Step 1)
Convert grams ammonium bromide (NH₄Br) to moles using its molar mass.
Molar Mass (NH₄Br): 14.007 g/mol + 4(1.008 g/mol) + 79.904 g/mol
Molar Mass (NH₄Br): 97.943 g/mol
8.42 grams NH₄Br 1 mole
----------------------------- x ------------------------ = 0.0860 moles NH₄Br
97.943 grams
(Step 2)
Calculate the volume of NH₄Br using the molarity equation. Then, convert liters (L) to milliliters (mL).
Molarity (M) = moles / volume (L)
0.193 M = 0.0860 moles / volume
(0.193 M) x volume = 0.0860 moles
volume = 0.445 L
1,000 mL = 1 L
0.445 L NH₄Br 1,000 mL
------------------------ x ------------------ = 445 mL NH₄Br
1 L
Help please I really don’t know what i’m doing.
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C₁₂H₂₂O₁₁
1 )
Molar mass = 12 x 12 + 22 x 1 + 11 x 16
= 144 + 22 + 176
= 342 g
2 )
100 mL of 1.0 M will contain 1.0 x0.100 = .1 mole of sucrose
0.1 mole of sucrose = 0.1 x 342 g = 34.2 g of sucrose.
So , mass of sucrose required is 34.2 g .
3 )
100 mL of .5 M sucrose = .100 x .5 mole of sucrose
= .05 mole of sucrose
.05 mole of sucrose = .05 x 342 g = 17.1 g of sucrose .
So , mass of sucrose required is 17.1 g .
Calculate the density of a piece of wood, in the units of g/mL, with a volume of 2.5L and a mass of 12.5 kg
Answer:
5 g / ml
Explanation:
Convert the values given to g and ml
12.5 kg = 12500 g
2.5 L = 2500 ml
12500 g / 2500 ml = 5 g/ml
The equilibrium constant for reaction (1) below is 276. Under the same conditions, what is the equilibrium constant of reaction (2) ? (Think about the basic definition !)
(1) 1/2 X2(g) + 1/2 Y2(g) ↔ XY(g)
(2) 2XY(g) ↔ X2(g) + Y2(g)
The equilibrium constant of the reaction is 76176.
What is the equilibrium constant?In chemistry, the equilibrium constant is used to show the extent to which we can convert reactants to products in a given chemical process. A large value of the equilibrium constant shows that most of the reactants are converted into products under the given conditions. A small value of the equilibrium constant shows that most of the reactants are not converted into products.
Thus, if we have the reactions;
(1) 1/2 X2(g) + 1/2 Y2(g) ↔ XY(g)
(2) 2XY(g) ↔ X2(g) + Y2(g)
It then follows that;
K1 = [XY]/[X2]^1/2 [Y2]^1/2
K2 = [XY]^2/[X2] [Y2]
It is clear that;
K2 = (K1)^2
K2 = (276)^2
K2 = 76176
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How many ml of 3M NaOH would it take to neutralize 120ml of 1M HCL?
Answer:
30ml
Explanation:
the acid-base solution just begins to turn pink and the pH reaches 7, indicating that the base has neutralized the acid. By reading the buret, it is found that 30 ml of NaOH was needed to neutralize the HCl.
Which of the following is not an organic compound?
OC6H14
O CO₂
OCH4
C12H22011
Answer:
Co2
Explanation
An organic compound includes Carbon and Hydrogen both bonded
Both flowering and nonflowering plants possess specialized structures that help them in reproduction. Conifers are nonflowering plants that possess special
to carry out reproduction. When conifers reproduce using these special structures, it is a form of
.
Conifers are non flowering plants that possess special cones to carry out reproduction. When conifers reproduce using these special structures, it is a form of Sexual reproduction.
How do conifers reproduce?Conifers are among the oldest living gymnosperms.These are a group of cone bearing seed plants.Typically, conifers are evergreen trees with needle-like leaves. E.g.: pine treesFlowering plants and conifers can reproduce by 2 main ways: sexual reproduction by means of seeds and asexual reproduction by means of separating and rooting part of a plant.However, seed production in conifers differs from that in flowering plants as conifers do not have showy petals like flowering plants. For sexual reproduction, conifers have male cones which produce pollen and female cones which contain ovules that develop into seeds. Gymnosperms (conifers) do not have their seeds enclosed in a fruit, unlike flowering plants. Instead, their seeds lie uncovered between a female cone's scales.Learn more about gymnosperms here:
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You have a 473 mL glass of lemonade with a concentration of 2.37 M.
The lemonade sits out on your counter for a couple of days, and 150 mL of water evaporates from the glass.
What is the new concentration of the lemonade?
The new concentration of the lemonade solution, given the data from the question is 3.47 M
Data obtained from the questionFrom the question given above, the following data were obtained:
Molarity of stock solution (M₁) = 2.37 MVolume of stock solution (V₁) = 473 mLVolume of water that evaporated = 150 mLVolume of new solution (V₂) = 473 - 150 = 323 mL Molarity of new solution (M₂) =? How to determine the molarity of the new solutionThe molarity of the new solution can be obtained by using the dilution formula as shown below:
M₁V₁ = M₂V₂
2.37 × 473 = M₂ × 323
1121.01 = M₂ × 323
Divide both side by 323
M₂ = 1121.01 / 323
M₂ = 3.47 M
Thus, the concentration of the new solution is 3.47 M
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Using the valence bond method, explain the structure of isocyanic acid in terms of the atomic bond method.
The structure of isocynide is
N=C
What is the importance of VSEPR theory?
Valence bond theory describes the electronic structure of molecule .The theory says that electrons fills the atomic orbitals of an atom within a molecule .
In the structure of isocynide there are triple bonds between Nitrogen and carbon . The bond length is 115.8pm and the bond angle is 180°. There is two pi and one sigma bond .
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The structure of isocynide is H--N=C
What is meant by valence bond?
Valence bond (VB) theory is a chemical bonding theory that describes the chemical bonding between two atoms. Like molecular orbital (MO) theory, it explains sticking using principles of quantum mechanics. According to valence bond theory, sticking is caused by the overlapping of half-filled atomic orbitals.
What is a valence bond structure?
Valence Bond theory represents covalent bond formation as well as the electronic form of molecules. The theory assumes that electrons inhabit atomic orbitals of individual atoms within a molecule, and that the electrons of one atom are drawn to the nucleus of another atom.
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balance the following nuclear reactions
Answer:
1.) ⁴₂He
2.) ⁶₂He
3.) ²⁴²₉₄Pu
4.) ¹₀n
Explanation:
The superscript represents the mass number, which is the total amount of protons and neutrons in an element.
The subscript represents the atomic number, which is the total amount of protons in an element.
You can identify the element based on the atomic number. For instance, all atoms with a subscript/atomic number of 2 must always be helium (He). An element with an atomic number of 0 is represented by the symbol "n". The mass number and atomic numbers must be equal on both sides of the reaction.
1.) ¹₁H + ³₁H → ⁴₂He
-----> Mass Number: 1 + 3 = 4
-----> Atomic Number: 1 + 1 = 2
2.) ⁹₄Be + ¹₁H → He + ⁶₂He
-----> Standard helium (He) has a mass number of 4 and an atomic number of 2
-----> Mass Number: 9 + 1 - 4 = 6
-----> Atomic Number: 4 + 1 - 2 = 2
3.) ²³⁹₉₂U + ⁴₂He → ²⁴²₉₄Pu + ¹₀n
-----> Mass Number: 239 + 4 - 1 = 242
-----> Atomic Number: 92 + 2 - 0 = 94
4.) ²⁷₁₃Al + ¹₀n → ²⁴₁₁Na + ⁴₂He
-----> Mass Number: 24 + 4 - 27 = 1
-----> Atomic Number: 11 + 2 - 13 = 0
environmental conditions of the ocean
The environmental conditions of the ocean are:
Light availabilityOxygen levelsWater movementSalinityDensity and pH.What are the environmental impacts on the ocean?In our oceans, there are known to be a lot of environmental conditions that are known to often affect the growth, survival and also the productivity of marine organisms. These are the ones listed above.
Note that the increased concentration of chemicals, e.g. nitrogen and phosphorus is one that can be harmful to marine life.
Hence, The environmental conditions of the ocean are:
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Is HCI an acid or a base?
Answer:
Strong Acid
Explanation:
Hope this helps! :)
What is the temperature in Kelvin of 0.46 mol of a gas that is at a pressure of 0.88 atm and volume of 675 mL?
Explanation:
we can use the "ideal gas law" :-
PV = nRT
p :- pressure ( pa )
V :- Volume ( m³ )
n :- amount of substance ( mol )
R :- Ideal gas constant ( 8.314 Jmol-¹ K-¹ )
T :- Temperature ( K)
a reaction is 50% complete in 2 hours and 75% complete in 4 hours.
what is the order of this reaction ?
Answer:
the half life of reaction is 2 hours which is consist half life of consist in the first order reaction has the order reaction is one
