Answer: Pb(NO3)2(aq) + 2KI(aq) —> PbI2(s) + 2KNO3(aq)
Explanation:
A chemist is studying the rate of the Haber synthesis: N2 + 3H2 2NH3
Starting with a closed reactor containing 1.25 mol/L of N2 and 0.50 mol/L of H2, the chemist finds that the H2 concentration has fallen to 0.25 mol/L in 44 seconds.What is the N2 concentration after 44 seconds?
Answer:
1.17 M
Explanation:
Step 1: Write the balanced equation
N₂ + 3 H₂ ⇒ 2 NH₃
Step 2: Calculate the rate of disappearance of H₂
We will use the following expression.
rH₂ = - Δ[H₂]/t = - (0.25 M - 0.50 M)/44 s = 0.0057 M/s
Step 3: Calculate the rate of disappearance of N₂
The molar ratio of N₂ to H₂ is 1:3.
0.0057 mol H₂/L.s × 1 mol N₂/3 mol H₂ = 0.0019 mol N₂/L.s
Step 4: Calculate the final concentration of N₂
We will use the following expression.
[N₂] = [N₂]₀ - rN₂ × t
[N₂] = 1.25 mol/L - 0.0019 mol/L.s × 44 s
[N₂] = 1.17 M
The first red (632.8 nm) Helium Neon gas laser was reported by White and Rigdon from Bell Labs in 1962. The laser was a discharge tube that was 1.2 m long with a 7 mm diameter. A He-Ne ratio of 10:1 was used with a total pressure of 0.00092 atm. This is a really low pressure with a really small amount of He and Ne. We want to try making a new laser with the same discharge tube with 5 mol Helium and 1 mol Neon. For the new laser with 5 mol He and 1 mol Ne, calculate the following quantities. Assume room temperature (298.15 K) and that the gasses are ideal.
a. What is the total volume (cm^3)?
b. What is the mole fraction of He?
c. What is the mole fraction of Ne?
d. What is the partial pressure of He (in atm)?
e. What is the partial pressure of Ne (in atm)?
f. What is the total pressure of the new laser tube (in atm)?
Answer:
a) Total Volume = 46.18 cm³
b) Mole[tex]_{fraction}[/tex] (He) = 0.8333
c) Mole[tex]_{fraction}[/tex] (Ne) = 0.1666
d) Partial Pressure P[tex]_{He}[/tex] = 2648.68 atm
e) Partial Pressure P[tex]_{Ne}[/tex] = 529.73 atm
f) total pressure of the new laser tube = 3178.41 atm
Explanation:
Given that;
height of of discharge tube h = 1.2 m = 1.2 × 100 = 120cm
diameter of the tube D = 7 mm = 0.7cm
Radius = D/2 = 0.7/2 = 0.35 cm
a) What is the total volume (cm³)?
Volume = πr²h
we substitute
Volume = π × (0.35)² × 120
Volume = 46.18 cm³
b) What is the mole fraction of He?
Mole fraction of Helium will be;
Mole[tex]_{fraction}[/tex] (He) = Moles of He / Total Moles ( He + Ne)
given that; 5 mol He and 1 mol Ne
Mole[tex]_{fraction}[/tex] (He) = 5 / ( 5 + 1 )
Mole[tex]_{fraction}[/tex] (He) = 5 / 6
Mole[tex]_{fraction}[/tex] (He) = 0.8333
c) What is the mole fraction of Ne?
Mole fraction of Neon will be;
Mole[tex]_{fraction}[/tex] (Ne) = Moles of Ne / Total Moles ( He + Ne)
given that; 5 mol He and 1 mol Ne
Mole[tex]_{fraction}[/tex] (Ne) = 1 / ( 5 + 1 )
Mole[tex]_{fraction}[/tex] (Ne) = 1 / 6
Mole[tex]_{fraction}[/tex] (Ne) = 0.1666
d) d. What is the partial pressure of He (in atm)?
using ideal gas equation;
P[tex]_{He}[/tex] = nRT/V
where n is number or amount of moles( 5 )
R is the universal gas constant ( 0.08205 L-atm.mol⁻¹K⁻¹
T is temperature ( 298.15 K)
And V is the volume; ( 46.18 cm³ = 46.18/1000 = 0.04618 L )
so we substitute
P[tex]_{He}[/tex] = (5 × 0.08205 × 298.15) / 0.04618
P[tex]_{He}[/tex] = 122.316 / 0.04618
P[tex]_{He}[/tex] = 2648.68 atm
e) What is the partial pressure of Ne (in atm)?
P[tex]_{Ne}[/tex] = (1 × 0.08205 × 298.15) / 0.04618
P[tex]_{Ne}[/tex] = 24.463 / 0.04618
P[tex]_{Ne}[/tex] = 529.73 atm
f) What is the total pressure of the new laser tube (in atm)?
total pressure of the new laser tube will be;
= P[tex]_{He}[/tex] + P[tex]_{Ne}[/tex]
= 2648.68 atm + 529.73 atm
= 3178.41 atm
total pressure of the new laser tube = 3178.41 atm
Calculate the moles of ammonia present in a 5.590 g sample if the molar mass of ammonia is 17.030 g/mol
Answer:
Number of moles = 0.328 moles.
Explanation:
Given the following data;
Mass = 5.590 g
Molar mass = 17.030 g/mol
To find the number of moles;
[tex] Number \; of \; moles = \frac {mass}{molar mass} [/tex]
Substituting into the equation, we have
[tex] Number \; of \; moles = \frac {5.590}{17.030} [/tex]
Number of moles = 0.328 moles.
Hydrogen peroxide is a versatile chemical, its uses include bleaching wood pulp and fabrics and substituting for chlorine in water purification. One reason for its versatility is that it can be either an oxidizing or reducing agent. For the following reactions, identify whether hydrogen peroxide is an oxidizing or reducing agent.
a) H2O2 (aq) + 2 Fe2+ (aq) + 2 H+ + 2H20 (1) + 2 Fe3+(aq)
b) 5 H2O2 (aq) + 2 MnO4 (aq) + 6 H+ (aq) → 8 H20 (1) + 2 Mn2+ (aq) + 5 O2 (g)
Answer:
Explanation:
a )
H₂O₂ (aq) + 2 Fe²⁺ (aq) + 2 H⁺ = 2H20 (l) + 2 Fe³⁺(aq)
Here oxidation number of Fe is increasing from + 2 to + 3 so it is being oxidized . Hence H₂O₂ is acting as oxidizing agent here .
b )
5 H₂O₂ (aq) + 2 MnO₄⁻¹ (aq) + 6 H⁺ (aq) → 8 H20 (l) + 2 Mn⁺² (aq) + 5O₂ (g)
In this reaction, oxidation number of Mn is reducing from + 7 to + 2 so it is being reduced . Here H₂O₂ is acting as reducing agent .
Graciella divided her grapes equally among 6 friends. If each friend received 16 grapes how many grapes did Graciella have?
Answer: She had 96 grapes.
Explanation:
Answer:
taiks
Explanation:
Calculate the mass in grams for 2.28 moles of N2?
Mole measure the number of elementary entities of a given substance that are present in a given sample. The mass of [tex]N_{2}[/tex] with 2.28 mol is 63.84g.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. Mole is inversely proportional to the molar mass of respective molecule. 1 mole contains Avogadro number of atoms, ions or molecules. Mole is extensive property as it depends on the quantity of substance.
mole of [tex]N_{2}[/tex] =given mass of [tex]N_{2}[/tex] ÷molar mass of nitrogen gas
mass of [tex]N_{2}[/tex]= mole of [tex]N_{2}[/tex] ×molar mass of nitrogen gas
mole of [tex]N_{2}[/tex]= 2.28mol
Substituting the values in the formula we get,
mass of [tex]N_{2}[/tex]= 2.28mol ×28g/mole
mass of [tex]N_{2}[/tex]= 2.28mol ×28
mass of [tex]N_{2}[/tex]=63.84g
Therefore the mass of [tex]N_{2}[/tex] is 63.84g with 2.28 mole is 63.84g.
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if a molecular formula is C8H12O2, what is the empirical formula
Answer:
C₄ H₆ O
Explanation:
The molecular formula of the compound is given as:
C₈ H₁₂ O₂
The molecular formula of a compound is expresses the true number of atoms within a compound.
The empirical formula gives the simplest ratio of the atoms within a compound.
Elements C H O
Number of atoms 8 12 2
Divide through by a
Common factor 8/2 12/2 2/2
4 6 1
The empirical formula therefore is C₄ H₆ O
Use this equation for the next question:
2NaOH + H2SO4 ® Na2SO4 + 2H20
If a reaction produces 0.75 moles Na2SO4, how many moles of NaOH were used?
0.75 moles NaOH
2 moles NaOH
.375 moles NaOH
1.5 moles NaOH
Suppose two students grab an end of a rope. Both shake a rope once in a upward direction to create crests traveling at each other. What would you see when crests meet? What type of interference does this show?
Answer:
This creates destructive interference.
Explanation:
When the two ends meet they will cancel each other out.
Both students are shaking the rope in the upward direction. Hence their crest will meet up and form the constructive interference pattern. The intensity of the increases.
What is constructive interference ?When two waves moves in phase, their crest or troughs add up and the amplitude of the wave increases. This phenomenon is called constructive interference.
If the two waves are passing out of phase to each other then they undergo destructive interference. The amplitude of the destructive interference pattern reduces from their initial values.
Here, both students are shaking the rope in the upward direction. Thus, they are in moving in phase. Hence their crest will meet up and form the constructive interference pattern. The intensity of the increases.
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In a laboratory setting, concentrations for solutions are measured in molarity, which is the number of moles per liter (mol/L). Concentrations are often converted to more common units on the labels of household products. For a particular brand of bleach, the concentration of sodium hypochlorite (NaClO) is reported on the bottle as 7.25% by mass. The following information can thus be used to calculate the molarity of NaClO in the bleach:
• 1L of bleach has a mass of 1,100 grams.
• 7.25% of the mass of bleach is NaClO.
• 1 mol of NaClO has a mass of 74.44 grams.
What is the molarity (mol/L) of NaClO in the bleach?
A.0.097
B.0.93
C.1.07
D.79.75
Answer:
its C
Explanation:
1/74.44 * 79.75 = 1.07
The molarity (mol/L) of NaClO in the bleach, given the data is 1.07 mol/L (Option C)
What is molarity?Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
How to determine the mass of NaClO in the bleachMass of bleach = 1100 gPercentage of NaClO = 7.25%Mass of NaClO = ?Mass of solute = percent × mass of solution
Mass of NaClO = 7.25% × 1100
Mass of NaClO = 0.0725 × 1100
Mass of NaClO = 79.75 g
How to determine the mole of NaClO Mass of NaClO = 79.75 gMolar mass of NaClO = 74.44 g/moleMole of NaClO =?Mole = mass / molar mass
Mole of NaClO = 79.75 / 74.44
Mole of NaClO = 1.07 mole
How to determine the molarity Mole of NaClO = 1.07 moleVolume = 1 L Molarity of NaClO =?Molarity = mole / Volume
Molarity of NaClO = 1.07 / 1
Molarity of NaClO = 1.07 mol/L
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Magnesium reacts with a silver nitrate solution
The reaction is represented by the ionic equation given
State why this reaction is considered a redox reaction
Answer: Mg oxidised to Mg++ and Ag+ reduced to Ag
Explanation:No ionic equation given!!
assume equation is Mg + 2Ag+ + 2NO3- —> Mg++ + 2Ag + 2NO3-
redox reaction: Ag gains an electron = reduced
Mg loseselectrons = oxidised
Set Grouper to 70%. How do you think this level of fishing will affect the populations of the other fish in the simulated reef? Explain your reasoning.
Answer:
Greatly affect.
Explanation:
This level of fishing will greatly affect the populations of the other fish in the simulated reef because overfishing disturbs the equilibrium in the marine ecosystem. One fish is a food of another fish or the big fish act as a controller which controls the population of other small fishes and in that way the ecosystem is present in equilibrium state so overfishing will greatly affect the marine ecosystem.
A student dissolves of aniline in of a solvent with a density of . The student notices that the volume of the solvent does not change when the aniline dissolves in it. Calculate the molarity and molality of the student's solution. Be sure each of your answer entries has the correct number of significant digits.
Answer:
Molarity: 0.21M
Molality: 0.20m
Explanation:
...dissolves 3.9g of aniline (C6H5NH2) in 200.mL of a solvent with a density of 1.05 g/mL...
To solve this question, we need to find the moles of aniline in 3.9g using its molar mass. Then, we need to find the kg and Liters of solution in order to find molarity (Moles/L solution) and molality (Moles/kg of solvent):
Moles aniline:
Molar mass:
6C: 6* 12.01g/mol = 72.06g/mol
7H: 7*1.008g/mol = 7.056g/mol
N: 1*14.007g/mol = 14.007g/mol
72.06g/mol+7.056g/mol+14.007g/mol = 93.123g/mol
Moles of 3.9g: 3.9g * (1mol / 93.123g) = 0.04188moles
Liters solution:
200mL * (1L / 1000mL) = 0.200L
kg solvent:
200mL * (1.05g/mL) * (1kg/1000g) = 0.210L
Molarity:
0.04188mol / 0.200L = 0.21M
Molality:
0.04188mol / 0.210L =0.20m
Hydrogen is the only atom that does not
have __electrons in the 1st energy
level/ shell.
Answer:
2
Explanation:
the number of H is 1, it means the only electron is on the energy level (1st level, s-electron). All the elements have 2 s-electrons on the 1st energy level.
In 1932, Robert Emerson and William Arnold used isolated spinach chloroplasts to determine that it requires 2,400 chlorophyll molecules to generate one O2 molecule. Based on this number and your understanding of where and how O2 is formed in chloroplasts, if a spinach chloroplast absorbs 720 photons, then how many resonance energy transfer reactions occur in the light-harvesting complexes and how many O2 molecules are formed
Answer:
There will be 216,000 energy transfer reactions
90 [tex]O_{2}[/tex] molecules will be formed
Explanation:
since 2400 chlorophyll molecules = ( 1 ) [tex]O_{2}[/tex] molecule
hence there will be 8 photons absorbed in this process
for 720 absorbed photons
The number of [tex]O_{2}[/tex] molecules formed = 720 / 8 = 90 molecules of [tex]O_{2}[/tex] molecule formed
Total number of resonance energy transfer reactions
( 1 ) [tex]O_{2}[/tex] molecule = 2400 molecules
hence 90 molecules of [tex]O_{2}[/tex]
= 2400 molecules * 90 molecules
= 216000 energy transfer reactions
I need help with 17,18,19,& 21
Answer:
17. tie hair up
wear goggles
18. i don't know
19. you light it on the side of the box
20. it should be orange because that is the safest.
21. you turn down the electricity thing
Samples of different materials, A and B, have the same mass, but the sample
of A is higher in density. Which statement could explain why this is so?
A. The sample of material A has greater volume than the sample of
material B.
B. The particles that make up material B are more closely packed
together than the particles that make up material A.
C. The particles that make up material A have more mass than the
particles that make up material B.
D. The particles that make up material B have more mass than the
particles that make up material A.
SUBMI
C. The particles that make up material A have more mass than the particles that make up material B.
The correct option is (c) The particles that make up material A have more mass than the particles that make up material B.
A substance containing atoms that are smaller, more massive, and close together will have a higher density. A substance will have a lower density if its larger, lighter atoms are spaced farther apart.The distances between the particles in each state of matter determine how dense solids, liquids, and gases are.Will the density of a material always be the same?Density is an intensive property. This means that regardless of the object's shape, size, or quantity, the density of that substance will always be the same. Even if you cut the object into a million pieces, they would still each have the same density. It is because density in an intensive property of matter.Learn more about Density of a material brainly.com/question/1733081
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*SCIENCE*
A nebula contains large amounts of dust and clouds. What role does gravity play inside of nebulae?
0 The gravitational pull between the gas and dusť matter leads to the formation of new galaxies.
0 The gravity pulls the gas and dust apart, leading to the formation of a larger nebula.
0 The gravitational pull between the gas and dust matter leads to the formation of new stars and planets.
0 There is no gravity inside nebulae because each dust particle is so small.
Answer:
The gravitational pull between the gas and dust matter leads to the formation of new galaxies
Explanation:
My teacher went over the answers and said that one was correct.
A nebula contains large amounts of dust and clouds. The gravitational pull between the gas and dusť matter leads to the formation of new galaxies does gravity play inside of nebulae. Therefore, option A is correct.
What is gravity ?Gravity is the force that pulls objects toward the center of a planet or other body. The gravitational force keeps all the planets in orbit around the sun.
Gravity pulls you toward the ground because all objects with mass, such as our Earth, actually bend and curve the fabric of the universe, known as spacetime. Gravity is the curvature of the earth.
A nebula is densely packed with dust and clouds.The gravity play a role inside nebulae, The gravitational pull between gas and dus matter leads to the formation of new galaxies.
Thus, option A is correct.
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What is the molarity of a solution that contains 25.3 g of NaCl in 111 mL of solution?
-14.6 M
-3.90 M
-0.25 M
-5.52 M
Answer:
"3.90M" if approximate
Explanation:
if u didn't understood why i converted volume from millilitres to litre then refer defination of Molarity.
hope it help:)
Based on your observations, why do you think the temperature of the NaC2H3O2 solution rose while that of the KCl solution fell
Answer:
Due to exothermic and endothermic reaction.
Explanation:
The temperature of NaC2H3O2 solution rises because exothermic reaction takes place in the solution while on the other hand, the temperature of KCl solution fell because endothermic reaction takes place. In exothermic reaction, heat energy is released to the surrounding whereas in endothermic reaction, heat energy is absorbed from the surrounding so that's why the temperature of one solution increases while the other decreases.
BALANCE THAI CHEMICAL EQUATION PLS, help:)
Answer:
4C₈H₄OH + 35O₂ → 32CO₂ + 10H₂O
Explanation:
The unbalanced reaction expression is given as:
C₈H₄OH + O₂ → CO₂ + H₂O
To solve this problem, we use a mathematical approach.
aC₈H₄OH + bO₂ → cCO₂ + dH₂O
Conserving C: 8a = c
H: 5a = 2d
O: a + 2b = 2c + d
Let a = 1, c = 8, d = [tex]\frac{5}{2}[/tex], b = 35
4C₈H₄OH + 35O₂ → 32CO₂ + 10H₂O
what is the correct name of Fe(CN)3?
Answer:
Iron(III) Cyanide
How can you model the cycling of matter in the Earth system?
Answer:
The cycling of matter is important to many Earth processes and to the survival of organisms the existing matter must cycle continuously for this planet to support life Water, carbon, nitrogen, phosphorus, and even rocks move through cycles If these materials did not cycle, Earth could not support life.
Explanation:
Earth activities depend on matter cycling, and for organisms to survive, this planet's surface must cycle with the flow of matter.
What is Earth system?Rocks, as well as water, carbon, nitrogen, and phosphorus, go through cycles. The planet Earth could not support life if these materials did not cycle.
Subsystems exist within the Earth system. These subsystems include the exosphere, atmosphere, hydrosphere, lithosphere and geosphere, also referred to as the lithosphere, and the living environment (biosphere).
These systems are powered by energy that comes from both the Sun and the interior of the Earth. Through processes known as biogeochemical cycles, nutrients and elements also move through these systems along with energy.
Therefore, Earth activities depend on matter cycling, and for organisms to survive, this planet's surface must cycle with the flow of matter.
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Indium has a tetragonal unit cell for which the a and c lattice parameters are 0.459 and 0.495 nm, respectively. (a) If the atomic packing factor and atomic radius are 0.693 and 0.1625 nm, respectively, determine the number of atoms in each unit cell. (b) The atomic weight of indium is 114.82 g/mol; compute its theoretical density. (a) Enter your answer for part (a) in accordance to the question statement atoms/unit cell (b) Enter your answer for part (b) in accordance to the question statement g/cm3
Answer:
A) 4 atoms/unit cell
B) 7.31 g/cm^3
Explanation:
A) Determine the number of atoms in each unit cell
attached below is the detailed solution
number of atoms per unit cell ( n ) = 4 atoms/unit cell
B) Given atomic weight of indium = 114.82 g/mol
hence the theoretical density = 7.31 g/cm^3
Attached below is a detailed solution of the question
Name the alkyne. Spelling and punctuation count. A seven carbon chain with a triple bond between carbon 1 and carbon 2. There is a C H 2 C H 2 C H 3 group attached to carbon 3.
Answer: IUPAC name of [tex]CH\equiv C-CH_2-CH_2-CH_2-CH_2-CH_3[/tex] will be hept-1-yne.
Explanation:
The IUPAC nomenclature of organic compounds are given as follows:
1. Select the longest possible carbon chain.
2. For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'hept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.
3. A suffix 'yne' is added at the end of the name if triple bond is present.
[tex]CH\equiv C-CH_2-CH_2-CH_2-CH_2-CH_3[/tex]
The IUPAC name will be hept-1-yne.
What is the molecular formula for the model below?
What are the non-living things that make up an ecosystem?
Answer:
abiotic things
abiotic things aren't living
Answer:
The non-living things would be the soil, rocks, and water. There are other things, but those are the main ones.
Bond length is the distance between the centers of two bonded atoms. On the potential energy curve, the bond length is the internuclear distance between the two atoms when the potential energy of the system reaches its lowest value. Consider that the atomic radius (sometimes called the covalent or bonding atomic radius) of an element is defined as one-half the distance between the bonded atoms in a homonuclear diatomic molecule. Actual bond lengths in molecules are determined experimentally by such methods as X-ray diffraction and microwave spectroscopy. However, these atomic radii values can be used to give an estimate of the upper limit of bond length in other (heteronuclear) molecules. Given that the atomic radii of H and Br are 37.0 pm and 115 pm , respectively, predict the upper limit of the bond length of the HBr molecule.
Answer:
152 pm
Explanation:
According to the question, we can estimate the bond length from the given values of the atomic radii. This now is the upper limit of the bond length for the molecule.
Since we have that;
Atomic radius of H= 37.0 pm
Atomic radius of Br = 115.0 pm
Bond length = Atomic radius of H + Atomic radius of Br
Bond length = 37.0 pm + 115.0 pm
Bond length = 152 pm
When 271. mg of a certain molecular compound X are dissolved in 25.0g of benzene C6H6, the freezing point of the solution is measured to be 0.5°C. Calculate the molar mass of X.
If you need any additional information on benzene, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to 2 significant digits.
molal freezing point depression constant (Kf)
°C·kg·mol−1 of benzene is 5.07
Answer:
11g/mol is the molar mass of X
Explanation:
The freezing point depression occurs in a solvent by the addition of a solute. The equation is:
ΔT = Kf*m*i
Where ΔT is change in freezing point (5.5°C - 0.5°C = 5.0°C)
Freezing point of benzene is 5.5°C
Kf is molal freezing point depression of benzene (5.07°C*kg/mol)
m is molality of the solution in moles/kg of solvent
And i is Van't Hoff factor (1 for all solutes dissolved in benzene)
Replacing to solve molality:
5.0°C = 5.07°C*kg/mol*m*1
0.986mol / kg = molality
As the mass of the solvent is 25.0g = 0.025kg:
0.025kg * (0.986mol/kg) = 0.0247 moles
As molar mass of X is the ratio between mass in grams and moles, the molar mass of X is:
0.271g / 0.0247moles =
11g/mol is the molar mass of XAllows ingestion and breaks down food so that nutrients can be absorbed???
Answer:
Salivation allows the ingestion of food while digestive juices aids breakdown of food and absorption of nutrients.
Explanation:
When food is taken into the mouth, the presence of food triggers a nervous reflex that causes the salivary gland to produce saliva in the mouth. Once the food particles have been ingested the digestive system breaks down the food into smaller components with the aid of the digestive juices.