117 mL of 0.210 M K₂S solution
Explanation:
The question asks about the volume of 0.210 M K₂S (potassium sulfide) solution required to completely react with 175 mL of 0.140 M Co(NO₃)₂ (cobalt(II) nitrate).
We have the chemical reaction:
K₂S + Co(NO₃)₂ → CoS + 2 KNO₃
molar concentration = number of moles / volume (L)
number of moles = molar concentration × volume
number of moles of Co(NO₃)₂ = 0.140 × 175 = 24.5 mmoles
We see from the chemical reaction that 1 mmole of Co(NO₃)₂ is reacting with 1 mmole of K₂S, so 24.5 mmoles of Co(NO₃)₂ are reacting with 24.5 mmoles of K₂S.
volume = number of moles / molar concentration
volume of K₂S solution = 24.5 / 0.210 = 117 mL
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7. If you plotted atomic radius versus first ionization
energy, would the graph reveal a direct or inverse
relationship?
Answer:
Neither
Explanation:
I plotted the graph of atomic radius vs. ionization energy for the first 10 elements.
It shows neither a direct nor an inverse relationship.
However, it is clear that atomic size decreases as ionization energy increases.
Plotting atomic radius against first ionization energy reveals an inverse relationship; as atomic radius increases, the first ionization energy typically decreases.
Explanation:If you plotted atomic radius versus first ionization energy, the graph would reveal an inverse relationship. This is because, generally, as atomic radius increases, the first ionization energy decreases. The ionization energy is affected by the principal quantum number (n) and the effective nuclear charge (Zeff), which relates to the strength of attraction between the nucleus and the valence electrons. Hence, a larger atomic radius means that the valence electrons are further from the nucleus and more shielded by other electrons, reducing the energy required to remove them. When plotting a graph of atomic radius versus first ionization energy, one would observe that points on the graph move downward as you go from top to bottom (from elements with a smaller atomic radius and higher ionization energy to elements with a larger atomic radius and lower ionization energy).
what is brownian motion
Answer: Brownian motion or pedesis is the random motion of particles suspended in a fluid resulting from their collision with the fast-moving molecules in the fluid. This pattern of motion typically alternates random fluctuations in a particle's position inside a fluid sub-domain with a relocation to another sub-domain.
Volume of 0.150 M NaOH solution required to neutralize 25mL of a 0.055 M HCl solution?
Equation of the reaction: NaOH(aq) + HCl(aq) ——-> H2O(l) + NaCl(aq)
9.17 mL
Explanation:In this question we are given;
Molarity of NaOH as 0.150 MMolarity of the acid, HCl as 0.055 MVolume of the acid, HCl as 25 mLEquation for the reaction as;NaOH(aq) + HCl(aq) → H2O(l) + NaCl(aq)
We are required to determine the volume of the alkali, NaOH used;
Step 1: Determine the moles of the acid, HClMolarity = Number of moles ÷ Volume
Thus, rearranging the formula;
Moles = Molarity × volume
= 0.055 M × 0.025 L
= 0.001375 moles
Step 2: Moles of the alkali, NaOHFrom the reaction; 1 mole of HCl reacts with 1 mole of NaOHTherefore;
Moles of HCl = Moles of NaOHHence; Moles of NaOH = 0.001375 moles
Step 3: Determine the volume of the alkali, NaOHFrom the previous equation;Molarity = Moles ÷ Volume
Rearranging the equation;Volume = Moles ÷ Molarity
Therefore;
Volume of NaOH = 0.001375 moles ÷ 0.150 M
= 0.00917 L, but, 1 L = 1000 mL
= 9.17 mL
Therefore, the volume of NaOH required is 9.17 mL
Acidic solutions contain high concentrations of
a. hydrogen ions
b. hydroxide ions
c. water
Answer:
hydrogen ions
Explanation:
because acid is the specie that have ability to donate proton or forming bond with electron pair
Acidic solutions have high concentrations of hydrogen ions.
When an acid dissociates in aqueous solution, it releases hydrogen ions, leading to increased H+ concentration and making the solution acidic. This is due to the higher proportion of H+ ions compared to hydroxide ions in acidic solutions.
Redox equations are _____ when the total increase in oxidation numbers equals the total decrease in oxidation numbers.
A. balanced
B. combined
C. different
D. equal
Answer:
The correct answer is A balanced
Explanation:
Redox reaction belongs to specific type of chemical or biochemical reaction in which oxidation and reduction occurs simultaneously.
For example
6CO2+12H2O=C6H12O6+6O2+6H2O
The above reaction is a redox reaction because in this reaction CO2 is reduced to form glucose whereas H2O is being oxidized to form O2.
Redox equations are balanced when the total increase in the oxidation number equals the total decrease in the oxidation number.
Answer:
A. balanced
Explanation:
Hello,
In this case, redox reactions undergo when one the elements at the reactants suffers an increase in its oxidation state and other elements suffers a decrease in its oxidation state. Thus, one could consider the following example:
[tex]H_2+I_2\rightarrow HI[/tex]
In that case, both hydrogen and iodine have zero as their oxidation states at the reactants whereas they go +1 and -1 respectively at the hydroiodic acid as shown below:
[tex]H_2^0+I_2^0\rightarrow H^+I^-[/tex]
In such a way, each hydrogen increases by 1 electron (two electrons in total as there two hydrogens) and iodine decreases by 1 electron (two electrons in total as there two iodines). Thus, the balance turns out:
[tex]H_2^0\rightarrow 2H^++2e^-\\I_2^0+2e^-\rightarrow 2I^-\\\\\\2H_2+2I_2\rightarrow 4HI\\\\H_2+I_2\rightarrow 2HI[/tex]
Therefore, redox equations are A. balanced when the total increase in oxidation numbers equals the total decrease in oxidation.
Best regards.
Apply the ideal gas law to solve problems
Question
A sample of gas that contains 21.0 moles at a pressure of 78.0 atm with a temperature of 900. Khas what volume?
• Use R = 0.08206 La
for the gas constant.
Answer:
Volume of gas ( V ) = 19.8935 L
Explanation:
Data Given:
no. of mole of gas (n) = 21.0 mole
Pressure P = 78.0 atm
Temperature T = 900 K
Ideal gas constant = 0.08206 L atm K⁻¹ mol⁻¹
Volume of gas = ?
Formula used for Ideal gases
PV = nRT
As we have to find volume of the gas:
We will rearrange the ideal gas equation as below:
V = nRT / P ........................................... (1)
Put value in equation (1)
V = 21.0 mol x 0.08206 L atm K⁻¹ mol⁻¹ x 900K / 78.0 atm
V = 19.8935 L
Volume of gas V = 19.8935 L
An insect population increases and then decreases as the food supply changes.
Which activity does this demonstrate?
self-regulation
uncontrolled population explosion
self-restoration
unchecked exponential growth
plz help i dont understand.. T.T
Answer:
self regulation
Explanation:
Answer:
A) Self-regulation
Explanation:
A self-regulated organism takes measures to balance its own survival with the scarce resources that the enviroment offers. In this case, the insect population is self-regulating because it is responding to changes in the food supply, and adapts itself accordingly.
In a way, self-regulation is like supply and demand. As supply of food decreases, but demand stays the same, scarcity ensues. This causes the need to reduce demand until a new equilibrium is reached, where demand and supply are equal.
Distinguish between dunes and loess
Answer:
Dunes are loose sand hills.
Loess is a compacted wind-blown formation of sediment.
Explanation:
Sand dunes are, as their name implies, made of sand which is itself made of tiny quartz pieces. Sand dunes are present where there is a ready source of broken down sandstone or other type of rock and wind to transport the sand. The dunes are mobile and loose and migrate over time.
Loess comes in vast formations and was created in a very different way. In the last ice age, winds from the north carried sediments loosened and ground by glaciers southwards. There, the sediments accumulated in large formations and became compacted over time.
How many grams of sodium hydroxide pellets, NaOH, are required to prepare 50 mL
of a 0.15 M solution.
Answer:
[tex]\large \boxed{\text{0.30 g }}[/tex]
Explanation:
1. Calculate the moles of NaOH
[tex]\text{Moles of NaOH} = \text{0.050 L solution} \times \dfrac{\text{0.15 mol NaOH}}{\text{1 L solution}} = \text{0.0075 mol NaOH}[/tex]
2. Calculate the mass of NaOH
[tex]\text{Mass of NaOH } = \text{0.0075 mol NaOH } \times \dfrac{\text{40.00 g NaOH }}{\text{1 mol NaOH }} = \textbf{0.30 g NaOH}\\\\\text{You need $\large \boxed{\textbf{0.30 g of NaOH}}$ to prepare the solution}[/tex]
Half of a sample of cobalt-60 decays after 5.26 years to form atoms of another element. Half of a sample of iodine-131 decays after 8.1 days to form atoms of another element. Which best explains this difference? 1Choice 1 Iodine-131 has a smaller atomic number than cobalt-60. 2Choice 2 Iodine-131 has a shorter half-life than cobalt-60. 3Choice 3 Iodine-131 has a smaller atomic mass than cobalt-60. 4Choice 4 Iodine-131 has half the radioactive energy of cobalt-60.
Iodine-131 has a shorter half-life than cobalt-60.
Explanation:We are given;
Half of a cobalt-60 sample decays after 5.26 years Half of an Iodine-131 sample decays after 8.1 daysWe are supposed to explain the difference between the two instances;
We need to define half life;
Half life is the time half of a given sample takes to decay leaving the other half of it.Therefore;If half of a cobalt-60 sample decays after 5.26 years then the half life of cobalt-60 is 5.26 years.On the other hand, if half of an Iodine-131 sample decays after 8.1 days, then the half life of Iodine-131 is 8.1 days.We can therefore, conclude that, Iodine-131 has a shorter half-life than cobalt-60.How do you read a data table?
Answer:
1st you read the column that has the subject then the tally column last you determine/read the frequency column
Explanation:
To separate a mixture of iron filings and salt, the
most efficient method wouid be
passing a magnet through the mixture
sorting the mixture by hand
distilling the mixture
The most efficient method would be to passing a magnet through the mixture.
Explanation:
a) passing a magnet through the mixture
It is the most efficient method to separate the iron fillings and the salt. The iron will be attracted by the magnet, because the presence of the unpaired electrons in the iron which induces paramagnetic properties and it will be attracted by the magnet, while the salt, which most probably sodium chloride which does not have unpaired electrons so it will be a diamagnetic compound that is not be attracted by a magnet.
b) sorting the mixture by hand
It is a ineficient way to separate the iron from the salt because it will require a lot of energy and time.
c) distilling the mixture
It is extremely hard to do that because iron and salt have very high boiling points.
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The best way to separate a mixture of iron filings and salt is to use a magnet, which attracts the iron. The other methods (sorting by hand, distilling) are less efficient and not suitable for this mix.
Explanation:The most efficient method to separate a mixture of iron filings and salt is to pass a magnet through the mixture. This is because iron is magnetic, while salt is not. The magnet will attract the iron filings and leave the salt behind. Following this process, you could rinse or carefully brush the iron filings off the magnet. This is a simple process called magnetic separation.
Sorting the mixture by hand or distilling the mixture is not recommended. Manually sorting can be tedious and might not effectively separate all the iron filings while distilling is usually used to separate liquid mixtures, not solids like iron filings and salt.
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In H2SO4, the oxidation number of H is , that of S is , and that of O is .
Answer:
Oxidation State of H in H₂SO₄ = +1
Oxidation State of S in H₂SO₄ = +6
Oxidation State of O in H₂SO₄ = -2
Explanation:
Oxidation number:
oxidation number is an apparent charge of an atom in a compound.
the total charge on a compound is zero
So for H₂SO₄ total charge = 0
Hydrogen donate an electron in H₂SO₄ and have +1 charge that is oxidation number
***so to calculate oxidation number of Sulfur and Oxygen in H₂SO₄
oxygen have 2- state
O.N. of H = 1+
O.N. of O = 2-
O.N. of S = x
H₂SO₄ =0
put values
(+1)2 + S + (-2)4=0
+2 + S -8 =0
S = 0-2 + 8
S = +6
****Now to find oxidation number of Oxygen
O.N. of H = 1+
O.N. of O = x
O.N. of S = +6
H₂SO₄ =0
put values
(+1)2 + (+6) + (O)4=0
+2 + 6 - (O) 4 =0
(O)4 = 0-2 - 8
(O)4 = -8
O = -8/4
O = -2
***Now to find oxidation number of Oxygen
O.N. of H = 1+
O.N. of O = x
O.N. of S = +6
H₂SO₄ =0
put values
(H)2 + (+6) + (-2)4=0
(H)2 + 6 - 8 =0
(H)2 = 0 - 6 + 8
(H)2 = +2
H = +2/2
H = +1
What's the mass of 14.4 mol F2
Answer:
Mass = 547.2 g
Explanation:
Given data;
Mass of F₂ = ?
Moles of F₂ = 14.4 mol
Solution:
Formula
Number of moles = mass/ molar mass
Mass = number of moles × molar mass
Molar mass of F₂ = 38 g/mol
Mass = 14.4 mol × 38 g/mol
Mass = 547.2 g
The mass of 14.4 moles of F₂ is 547.2 grams.
To solve this, we need to know the molar mass of fluorine gas (F₂). Each fluorine atom has an atomic mass of approximately 19.0 g/mol. Since F₂ is a diatomic molecule, its molar mass is:
19.0 g/mol × 2 = 38.0 g/mol
Now, we multiply the molar mass by the number of moles given:
14.4 mol × 38.0 g/mol = 547.2 g
Thus, the mass of 14.4 moles of F₂ is 547.2 grams.
3)
How many atoms are in 14 moles of cadmium?
Answer:
[tex]8.4322\times10^{24} atoms[/tex] atoms are in 14 moles of cadmium.
Explanation:
Cadmium is a white and silvery metal that is found in the curst of the earth.During the production process of metals such as lead, copper, zinc, cadmium is extracted
Cadmium is present in some foods and is emitted when fossil fuels like as coal and oil is used, smoking cigarettes. It is used in craft glazes, metal batteries, and coatings.
We know that 1 mole of Cadmium (Cd contains) 6.023*1023 atoms, which is Avogadro's number.
So in 14 Grams of Cadmium, the number of atoms present is,
=>14×number atoms present in one cadmium atom
=>[tex]14\times 6.023\times10^{23}[/tex]
=>[tex]8.4322\times10^{24} atoms[/tex]
The number of atoms of Cadmium present in 14 moles is 84.322 [tex]\rm \bold{\times\;10^2^3}[/tex] atoms.
The number of atoms in a mole of compounds can be given by the Avagadro number. The Avagadro number has been equal to 6.023 [tex]\rm \bold{\times\;10^2^3}[/tex]
Thus, 1 mole = 6.023 [tex]\rm \bold{\times\;10^2^3}[/tex] atoms
The given element has been Cadmium. The moles of Cadmium is 14 moles.
By simplifying with unitary method:
1 mole = 6.023 [tex]\rm \bold{\times\;10^2^3}[/tex] atoms
14 moles = [tex]\rm \dfrac{6.023\;\times\;10^2^3}{1}\;\times\;14[/tex] atoms
14 moles of Cadmium = 84.322 [tex]\rm \bold{\times\;10^2^3}[/tex] atoms.
The number of atoms of Cadmium present in 14 moles is 84.322 [tex]\rm \bold{\times\;10^2^3}[/tex] atoms.
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Solid nickel reacts with aqueous nitric acid (HNO3) to form aqueous nickel (III) nitrate and hydrogen gas. Write out and balance the chemical equation, including phases.
Ni (s) + 2 HNO₃ (aq) → Ni(NO₃)₂ (aq) + H₂ (g)
Explanation:
We have the following balanced chemical equation:
Ni (s) + 2 HNO₃ (aq) → Ni(NO₃)₂ (aq) + H₂ (g)
where:
(aq) - aqueous (dissolved in water)
(g) - gaseous
To balance the chemical equation the number of atoms of each element entering the reaction have to be equal to the number of atoms of each element leaving the reaction, in order to conserve the mass.
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There are diffrent types of cells for every job in your body. How do we refer to those cells that develop differently?
A) They are unidirectional.
B) They are unorganized.
C) They are specialized.
D) They are usually damaged.
Answer:
The correct answer is c they are specialized.
Explanation:
Human body contain various types of cells and each specific type of cell performs specific functions.
For example nerve cells help in propagation of action potential from one neuron to the next.
Heart cells of our body act as a pump.Basically heart cells pump blood.
Blood cells helps in transport of various biomolecules and fight against invaded pathogens.
Lung cells helps in the exchange of oxygen and carbon dioxide gas to and from our body.
kidney cells helps in the filtration of blood and formation of urine
Answer: (C They are specialized
Explanation:
Number 9.56 questions, a, b , c
Answer:
Explanation:
Chemical equation;
2C₁₀H₂₂ + 31O₂ → 20CO₂ + 22H₂O
a) how many moles of O₂ are needed to completely react with 1.0 mole of C₁₀H₂₂?
Given data:
Moles of C₁₀H₂₂ = 1.0 mol
Moles of O₂ needed = ?
Solution:
we will compare the moles of C₁₀H₂₂ with O₂.
C₁₀H₂₂ : O₂
2 : 31
1.0 : 31/2×1.0 = 15.5 mol
So 15.5 moles of oxygen are needed to react with 1.0 moles of C₁₀H₂₂ .
B) if a car produces 44 g of CO₂, how many grams of C₁₀H₂₂ are used up in the reaction?
Given data:
Mass of CO₂ = 44 g
Mass of C₁₀H₂₂ = ?
Solution:
Number of moles of CO₂:
Number of moles = mass/ molar mass
Number of moles = 44 g/ 44 g/mol
Number of moles = 1 mol
Now we will compare the moles of CO₂ with C₁₀H₂₂.
CO₂ : C₁₀H₂₂
20 : 2
1 : 2/20×1 = 0.1 mol
Mass of C₁₀H₂₂:
Mass = number of moles × molar mass
Mass = 0.1 mol × 142.3 g/mol
Mass = 14.23 g
14.23 g of C₁₀H₂₂ are used up in this reaction.
c) if you add 28.8 g of C₁₀H₂₂ to your fuel, how many moles of O₂ are used up in the reaction?
Given data:
Mass of C₁₀H₂₂ = 28.8 g
Moles of oxygen used = ?
Solution:
Number of moles of C₁₀H₂₂ = mass/ molar mass
Number of moles of C₁₀H₂₂ = 28.8 g /142.3 g/mol
Number of moles of C₁₀H₂₂ = 0.20 mol
Now we will compare the moles of C₁₀H₂₂ with oxygen.
C₁₀H₂₂ : O₂
2 : 31
0.20 : 31/2×0.20 = 3.1 mol
By adding 28.8 g of C₁₀H₂₂ 3.1 moles of oxygen will used.
How many moles of Na2SO4, are produced from 7.00 moles of (NH4)2SO4?
Answer:The number of mole in the compounds are:
A. 6.60 g of (NH₄)₂SO₄ contains 0.05 mole.
B. 4.5 kg Ca(OH)₂ contains 60.81 moles
The mole of a substance is related to its mass and molar mass according to the equation:
With the above formula, we can obtain the answer to the questions given above. This is illustrated below:
A. Determination of the number of mole in 6.60 g of (NH₄)₂SO₄
Molar mass of (NH₄)₂SO₄ = 2[14 + (4×1)] + 32 + (4×16)
= 2[14 + 4] + 32 + 64
= 2[18] + 32 + 64
= 36 + 32 + 64
= 132 g/mol
Mass of NH₄)₂SO₄ = 6.60 g
Mole of NH₄)₂SO₄ =?
Mole of NH₄)₂SO₄ =
Mole of NH₄)₂SO₄ = 0.05 mole
Thus, 6.60 g of (NH₄)₂SO₄ contains 0.05 mole.
B. Determination of the number of mole in 4.5 kg Ca(OH)₂
Molar mass of Ca(OH)₂ = 40 + 2(16 + 1)
= 40 + 2(17)
= 40 + 34
= 74 g/mol
Mass of Ca(OH)₂ = 4.5 kg
= 4.5 × 1000
= 4500 g
Mole of Ca(OH)₂ =?
Mole of Ca(OH)₂ =
Mole of Ca(OH)₂ = 60.81 moles
Thus, 4.5 kg Ca(OH)₂ contains 60.81 moles
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what is the energy of a wave with a frequency of 6.58x10¹³ Hz
energy of the wave is equal to 43.6 × 10⁻²¹ J
Explanation:
The energy of a wave knowing the frequency is calculated using the following formula:
energy = plank constant × frequency
energy = 6.63 x 10⁻³⁴ J·s × 6.58 × 10¹³ s⁻¹ (Hz)
energy = 43.6 × 10⁻²¹ J
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Message are carried from the eye to the brain by
Answer:Brain
Explanation:
Answer:
It is the nerves :)
Explanation:
Explain how two compounds can have the same percentage composition but different molecular masses?
Two compounds can have same percentage composition but different molar mass, where the composition of each element contributed into the total mass can be same for two compounds irrespective of their molar mass.
What is percentage composition?Percentage composition of a compound is the mass by percent of its constituent elements of groups. Molecular mass of a compound is the sum of the mass of its constituent elements.
Let AB₂ be a compound and the total molecular mass be X,the percentage of A be a% and that of b being b%, where b will be greater since there are 2 B groups.
There can be compounds with a % of A and b% of B but with different molar mass. Thus, there will be compounds which contains same mass percent of one elements.
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Final answer:
Two compounds can have the same percentage composition but different molecular masses because they can be structural isomers, which have the same number and types of atoms but arranged differently resulting in different properties and molar masses.
Explanation:
Compounds with Same Percentage Composition and Different Molecular Masses
Two compounds can have the same percentage composition but different molecular masses due to the phenomenon of isomerism. Isomers are molecules that have the same molecular formula, meaning the same number and types of atoms, but with the atoms arranged in a different manner. This results in different structures and potentially different physical properties, including molecular masses. The percentage composition only reflects what percent of the compound's total mass is made up by each type of atom, regardless of the compound's structure.
For instance, structural isomers have the same chemical composition but different arrangements of atoms and different chemical bonding, leading to different molar masses. To determine the percentage composition, one would divide the atomic mass of each element by the total molar mass of the molecule. However, this calculation doesn't account for the structural differences between isomers.
Examples of this include butane and isobutane, both of which have the molecular formula C4H10 but differ in structure and therefore in their molar mass. Such scenarios illustrate the importance of not only considering the percentage composition but also the molecular structure when identifying and comparing substances.
What is the procedure for ranking plants
Taxonomy is the procedure for ranking plants.
Explanation:
The plants are ranked depending upon the resemblances and differences it has from another kind of plants. They can be ranked depending upon their leaves, roots, stems and other structures. They are defined into more general categories depending on the similar traits in the same group.
The plants are broadly classified into vascular and non vascular .Example, a flowering plant is a higher green plant and based on its gross structure does lie in the kingdom of Plantae, not in fungus or bacteria.
What is quantum model of the atom often called.
Answer:
Quantum mechanics or physics
Explanation:
For each of the four single-displacement reactions, describe what happened in rachel well. if a chemical reaction occured, write a balanced equation for it. Then using the A, B symbols, write a general equation for a single-displacement reaction.
Answer:
Explanation:
Single replacement:
It is the reaction in which one elements replace the other element in compound.
General equation:
AB + C → AC + B
1) zinc and Copper sulfate
Zn + CuSO₄ → ZnSO₄ + Cu
Zinc is more reactive than copper it displaces the copper from copper sulfate and form zinc sulfate.
2) Aluminium and Copper sulfate
2Al + 3CuSO₄ → Al₂(SO₄)₃ + 3Cu
Aluminium is more reactive than copper it displaces the copper from copper sulfate and form aluminium sulfate.
3) Zinc and silver nitrate
Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag
zinc is more reactive than silver it displaces the silver from silver nitrate and form zinc nitrate.
4) copper and silver nitrate
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
copper is more reactive than silver it displaces the silver from silver nitrate and form copper nitrate.
Final answer:
In a single-displacement reaction, one element replaces another element in a compound. The general equation for a single-displacement reaction is A + BC → AC + B.
Explanation:
In a single-displacement reaction, one element replaces another element in a compound. These reactions occur when a more reactive element displaces a less reactive element from its compound.
For example, in the reaction F2 + FeI3, fluorine (F2) replaces iodine (I) in the compound FeI3, resulting in the formation of FeF3:
2F2 + FeI3 → 2FeF3 + 3I2
The general equation for a single-displacement reaction can be written as A + BC → AC + B, where A is the more reactive element that displaces B from its compound BC.
Which substance can not be decomposed by chemical means ?
Answer:
Elements :)
Explanation:
Neon (Ne), being an element, is the substance that cannot be decomposed by chemical means from the given list. All other options are chemical compounds that can be decomposed into elements.
The question is about identifying a substance that cannot be decomposed by chemical means from a given list. Substances that cannot be chemically decomposed are known as elements, which are the most basic form of matter that cannot be broken down into simpler substances. Based on the options provided (Ne, N₂O, HF, H₂O), Neon (Ne) is an element and thus cannot be decomposed chemically into simpler substances.
The rest of the substances are chemical compounds: N₂O (nitrous oxide), HF (hydrogen fluoride), and H2O (water). These compounds can be decomposed into their elements by chemical reactions, such as hydrolysis or electrolysis for water. Therefore, the correct answer is Ne, which is an inert noble gas and an element that cannot be decomposed by chemical means. Option A
What is a mixture of small pieces of rock with decayed plants and animals
Answer:
soil A mixture of weathered rock and decayed plants and animals. Plants need soil to grow. Soil is the top layer of Earth's land surface, in many places.
Explanation:
Soil is the mixture composed of eroded rocks, organic matter from decayed plants and animals, minerals, and other materials vital for plant growth and ecological foundations.
The material you're asking about, which is a mixture of small pieces of rock with decayed plants and animals, is known as soil. Soil is a blend of various components, including eroded rock, minerals, organic matter, and other materials. These ingredients are critical for supporting plant life and form the fundamental layers of terrestrial ecosystems.
The organic matter in soil typically comes from decaying plant and animal matter, which can vary from freshly fallen leaves to more fully decomposed materials, known as detritus. Additionally, soil may include biologic precipitates, fragments of rocks such as sand, silt, or clay, and in some cases, paths created by earthworms and burrows from moles.
Like He, the Li2+ ion is a single-electron system (Problem 5.94). What wavelength of light in nm must be absorbed to
promote the electron in Li2+ from n = 1 to n = 4?
Answer:[tex]1.08\times 10^{-8}m[/tex]
Explanation:
Let [tex]E_{n}[/tex] be the energy of the electron in [tex]n[/tex]th orbit.
According to Bohr's model,
[tex]E_{n}=\frac{-kz^{2}}{n^{2}}[/tex]
where [tex]k=2.179\times 10^{-18}J[/tex]
[tex]Z[/tex] is the atomic number
[tex]n[/tex] is the orbit number.
Given,[tex]z=3[/tex]
Energy required for transition from [tex]n=1[/tex] to [tex]n=4[/tex] is [tex]\frac{k(3)^{2}}{1^{2}}-\frac{k(3)^{2}}{4^{2}}=\frac{15k\times 9}{16} =18.38\times 10^{-18}J[/tex]
Since,wave length is [tex]\frac{hc}{E}[/tex]
where [tex]h[/tex] is the plancks constant.
[tex]c[/tex] is the speed of light.
[tex]c=3\times 10^{8}\\h=6.63\times 10^{-34}m^{2}KgS^{-1}[/tex]
So,wave length is [tex]\frac{6.63\times 10^{-34} \times 3\times 10^{8}}{18.38\times 10^{-18}} =1.08\times 10^{-8}m[/tex]
Final answer:
To determine the wavelength of light absorbed by a Li2+ ion moving from n = 1 to n = 4, we use the Bohr model and adjust the Rydberg formula by the square of the nuclear charge. This yields the energy difference, which can be converted to wavelength using the relationship between energy, wavelength, and the speed of light.
Explanation:
The question involves using the Bohr model of the atom to calculate the wavelength of light that must be absorbed to excite an electron. For a single-electron system like the Li2+ ion, the energy difference between two orbits (n = 1 and n = 4) can be calculated using the Rydberg formula for hydrogen-like atoms:
E = Rydberg constant * (1/n12 - 1/n22)
Here, n1 and n2 are the principal quantum numbers of the initial and final states, respectively. Since the Li2+ ion has a higher nuclear charge than hydrogen, we must account for this by multiplying the Rydberg constant by the square of the nuclear charge (Z2). The energy of the photon absorbed is then transformed into a wavelength using the relationship:
c =
λ * E
Where c is the speed of light and
λ is the wavelength. By plugging in the appropriate values and constants, we can solve for the wavelength of light in nm.
1. How many moles of AgNO3 are in 15.0 g?
Answer: 0.088 moles
Explanation:
Parameters given:
Mass of AgNO3 = 15.0g
To know the number of moles, given such parameter, we need to find and use the molecuar weight formular. The molecuar weight is mass per mole
Molecular weight = mass / mole
Molecular weight of AgNO3
Ag + N + 03
107.8682 + 14.0067 + 15.9994(3)
(Note, that the weight of each compounds are standards)
= 169.8731g/mole
Using our molecular weight formular
Moles of AgNO3 in 15.0g
Let Number of Moles be represented as Y
169.8731g/mole = 15.0g / Y
Therefore,
Y = 169.8731 / 15.0g
Y = 0.088 moles
No of Moles of AgNo3 in 15.0g = 0.088moles
Which answer accurately describes the difference between speed and velocity? Read each answer choice carefully.
Question 4 options:
A. If speed is constant, then velocity is also constant.
B. Speed requires direction. The direction doesn't matter when calculating velocity.
C. Speed is the distance per unit of time. Velocity is the displacement per unit of time.
Answer:
C. Speed is the distance per unit of time. Velocity is the displacement per unit of time.
This answer accurately describes the difference between speed and velocity.
Explanation:
A. If speed is constant, then velocity is also constant.
The above statement is not correct, the correct statement is if speed is constant its velocity is not necessarily constant.
Example: An object in uniform circular motion has constant speed but its velocity changes at every instant due to change in direction.
B. Speed requires direction. The direction doesn't matter when calculating velocity.
The above statement is not correct, the correct statement is
Speed does not require direction. The direction is necessary for calculating velocity.
Speed, a scalar quantity, requires magnitude only not the direction.
Velocity is vector quantity, requires magnitude as well as direction.
C. Speed is the distance per unit of time. Velocity is the displacement per unit of time.
The above statement is correct i.e.
Speed is the distance per unit of time. Velocity is the displacement per unit of time.