The mass of butane, C₄H₁₀ needed to produce 70.8 g of carbon dioxide, CO₂ is 23.3 g
How do i determine the mass of butane needed?First, we shall write the balanced equation for the reaction. Details below:
2C₄H₁₀ + 13O₂ -> 8CO₂ + 10H₂O
Molar mass of C₄H₁₀ = 58 g/molMass of C₄H₁₀ from the balanced equation = 2 × 58 = 116 g Molar mass of CO₂ = 44 g/molMass of CO₂ from the balanced equation = 8 × 44 = 352 gFrom the balanced equation above,
352 g of CO₂ were obtained from 1 16 g of C₄H₁₀
Finally, we shall determine the mass of butane, C₄H₁₀ neeeded to produce 70.8 g of carbon dioxide, CO₂. Details below:
From the balanced equation above,
352 g of CO₂ were obtained from 116 g of C₄H₁₀
Therefore,
70.8 g of CO₂ will be obtain from = (70.8 × 116) / 352 = 23.3 g of C₄H₁₀
Thus, the mass of butane needed is 23.3 g
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Please help, find the pressure with the gas
Answer:
Pressure of the gas =766.4 mmHg.
Explanation:
Gas pressure greater than atmospheric pressure = Atmospheric pressure + Height
745.0 mm + 26.4 cm = 766.4 mmHg.
4. The complete chemical equations for reactions a-e on the Experimental Page are
listed below. Balance each equation by placing the proper coefficient in front c
each chemical formula so that each side of the equation has the same number
atoms of each element.
NaOH +
HCI →>>
NaCl +
HOH
While isobaric heat can be measured by using the coffee cup calorimeter, what kind of device would be needed to measure the reaction heat under isochoric condition? Please search literature to answer the question.
To measure the reaction heat more accurately at isobaric condition, what modification(s) would you suggest making on the coffee cup calorimeter? Please justify the suggested change(s).
To measure reaction heat under isochoric conditions, a bomb calorimeter is needed.
This device is designed to maintain a constant volume (isochoric) during the reaction, allowing for accurate measurement of reaction heat. To improve the accuracy of the coffee cup calorimeter for measuring reaction heat under isobaric conditions, a modification that could be made is to use a stirring device to ensure uniform mixing of the reactants and to minimize heat loss to the surroundings.
Additionally, a lid with a small hole could be placed over the top of the calorimeter to prevent heat loss while still allowing for pressure equalization. These modifications would help to minimize errors in heat measurement and improve the accuracy of the results obtained.
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What is the calibration of this graduated cylinder? calibration
A. 5 mL
B. 2 mL
C. 1 mL
D. 10 mL
The answer is 1ml. The answer is 1ml because of calibration of this graduated cylinder
Answer:
1 mL
Explanation:
According to your definition, it is the difference between marked spaces divided by the # of spaces between marked values.
Difference between 2 marked values: 5 mL
# Of Spaces between marked values: 5
Calibration: 5 mL / 5 mL = 1 mL
A student dissolves 11.8 g of sodium hydroxide (NaOH) in 250. g of water in a well-insulated open cup. He then observes the temperature of the water rise
from 20.0 °C to 31.3 °C over the course of 6.7 minutes.
Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
NaOH(s) -. Nat (ag) + OH (ag)
You can make any reasonable assumptions about the physical properties of the solution. Be sure answers you calculate using measured data are rounded to 3
significant digits.
Note for advanced students: It's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the known and
published values for this reaction.
See image attached
The reaction in the experiment is exothermic reaction and 158.72 kilo joules at 34.51 degrees celsius is released.
How to calculate change in enthalpy We must ascertain the enthalpy in the second experiment. Using the data from the first and second experiments, we will determine this. We can infer from the data of the first experiment that either heat was released or carried out in the second experiment. This benzoic acid is agitated, producing heat that is equivalent to the heat produced by water. Heat has been produced as a result of the commotion in c. 6 h. The experiment's acid weighs 6 grams, and this measurement is in joules per gram. A unit of water heat is 6 grams. The specific heat of the water used in the experiment is 4.184 joules per gram per 1000 milliliters temperature difference in the first experiment is 21255.51 minus 21 degrees Celsius. We will first need to determine the calorimeter C's heat capacity, and then we will need to determine the temperature change. The result will be 142.389 kilo joules and 158.72 kilo joules at 34.51 degrees celsius.For more information on change in enthalpy kindly visit to
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The enthalpy of vaporization of ethanol is 38.56 kJ/mol at its boiling point (78°C). Calculate the value of AS sur When 1.00 mole of ethanol is vaporized at 78°C and 1.00 atm.
-1.1 10² J/K mol
4.92 × 102 J/K mol
1.1 102 J/K mol
-4.92 102 J/K mol
The enthalpy of vaporization of ethanol is 38.56 kJ/mol at its boiling point (78°C). Calculate the value of entropy of surrounding when 1.00 mole of ethanol is vaporized at 78°C and 1.00 atm is -110.2 kJ/mol K. The correct option is option A.
Entropy is the measurement of the amount of thermal energy for each degree of temperature in a system that cannot be used for productive work. Entropy is a measure of a system's molecular disorder or unpredictability since work is produced by organised molecular motion.
Entropy theory offers profound understanding of the pattern of impulsive shifts for numerous commonplace events. A standout of 19th-century physics is its invention by the German scientist Rudolf Clausius in 1850.
C[tex]_2[/tex]H[tex]_5[/tex]OH(l) → C[tex]_2[/tex]H[tex]_5[/tex]OH(g)
ΔSsystem= 38.56 /351
=110.2 kJ/mol K
ΔSsurrounding=-110.2 kJ/mol K
ΔSuniverse=0
Therefore, the correct option is option A.
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The specific heat of octane, C8H18 (1), is 2.22 J/g K. The specific heat of water is 4.184 J/gK.. Does it take more energy to increase 1 mole of water by 10 °C or 1 mole of octane?
Explanation:
The molar mass of octane (C8H18) is approximately 114 g/mol.
To find the energy required to increase 1 mole of substance by 10°C, we can use the formula:
ΔE = n * C * ΔT
where ΔE is the energy required, n is the number of moles, C is the specific heat, and ΔT is the change in temperature.
For water, n = 1 mol, C = 4.184 J/gK, and ΔT = 10°C.
So, the energy required to increase 1 mole of water by 10°C is:
ΔE_water = n * C_water * ΔT
= 1 mol * 4.184 J/gK * 10 K
= 41.84 J
For octane, n = 1 mol, C = 2.22 J/gK, and ΔT = 10°C.
So, the energy required to increase 1 mole of octane by 10°C is:
ΔE_octane = n * C_octane * ΔT
= 1 mol * 2.22 J/gK * 10 K
= 22.2 J
Therefore, it takes more energy to increase 1 mole of water by 10°C than 1 mole of octane.
What does a high specific heat tell about a substance?
OA. The substance is probably a metal.
B. It is hard to change the temperature of the substance.
C. The substance has very strong molecular bonds.
D. The substance has high melting and boiling points.
SUBMIT
Answer:
B. It is hard to change the temperature of the substance
AP Environmental Science: According to the diagram, crude oil can be heated and separated into various components. In one barrel of oil, 22 percent is refined into gasoline and 38 percent into diesel fuel.
When the price of a barrel of oil increases, which of the following statements is the most accurate prediction of what will happen?
- The price of gasoline will increase in direct proportion to the increase in a barrel of oil.
- Bitumen for roads and roofing will be affected in supply but not in price.
- Diesel fuels will not be affected in price and can be manufactured from ethanol.
- The price of jet fuel will follow the inverse relationship and increase quickly in cost.
Okay, here are the key points to consider:
- Crude oil is separated into various components like gasoline, diesel fuel, jet fuel, bitumen, etc.
- A barrel of oil contains 22% gasoline and 38% diesel fuel. So these components make up a major portion of the oil.
- When the price of a barrel of oil increases, the costs to produce these components like gasoline and diesel also go up.
- So the prices of gasoline, diesel fuel and other components are directly linked to the price of crude oil. They will likely increase proportionally if oil price rises.
- Bitumen may be affected in supply but its price could still adjust based on supply and demand. It's linked to oil price indirectly.
- Diesel fuel price will also likely rise with oil price increase. It cannot be produced just from ethanol. It requires crude oil.
- Jet fuel price will also follow the increase in oil price. It's not inverse.
So among the options, the choice that is most accurate is:
The price of gasoline will increase in direct proportion to the increase in a barrel of oil.
The other options are not fully supported. Diesel and jet fuel prices will rise, bitumen may see some supply impact but prices will adjust, and prices are directly linked to oil prices, not inversely.
Let me know if you need more explanation.
2C +2H yield C2H4 Delta H=+52.4 kj/mol
What is the kj of energy absorbed for every mole of carbon reacted
The kJ of the energy absorbed for the every mole of the carbon reacted is 104.8 kJ.
The chemical equation is as :
2C + 2H ---> C₂H₄ , ΔH = + 52.4 kJ/mol
The ΔH is the enthalpy change that is determined by the subtracting the energy of the reactants to the products.
The ΔH = energy of the products - energy of the reactants
The expression for the energy is as :
q = n ΔH
Where,
n = number of the moles
ΔH = enthalpy change
The kJ of the energy absorbed for the every mole of the carbon reacted :
q = 2 mol × 52.4 kJ/mol
q = 104.8 kJ
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A fjord is _____ .
a high mountain
a steep-sided glacial valley
an oceanic mountain range
a glacial plain
Answer:
a steep-sided glacial valley
Explanation:
A fjord is a long, narrow inlet with steep sides or cliffs, created by a glacier. It is a long, deep, narrow body of water that reaches far inland. Fjords are found mainly in Norway, Chile, New Zealand, Canada, Greenland, and Alaska. They are formed when a glacier cuts a U-shaped valley by ice segregation and abrasion of the surrounding bedrock. According to the standard model, glaciers formed in pre-glacial valleys with a gently sloping valley floor. The work of the glacier then left an over deepened U-shaped valley that ends abruptly at a valley or trough end. Such valleys are fjords when flooded by the ocean. Thresholds above sea level create freshwater lakes.
NH4NO3 is ammonium nitrate is used for supplies ammonium and nitrate ions.
a. Calculate the percentage nitrogen, hydrogen and oxygen by mass in this fertilizer.
b. Calculate the mass of nitrogen in 500kg of ammonium nitrate
Relative atomic masses: H = 1; N = 14 ; O= 16
What is the quantity of Fe2+ ion reacting, in moles?
100 mL of a 0.500 M solution of Fe2+ is added to 100 mL of a 0.100 M solution of MnO4-
The balanced chemical equation for the reaction between Fe2+ and MnO4- in acidic solution is :
5 Fe2+ + MnO4- + 8 H+ -> 5 Fe3+ + Mn2+ + 4 H2O
From the equation, we can see that 1 mole of MnO4- reacts with 5 moles of Fe2+.
The initial moles of Fe2+ in the solution are :
0.500 mol/L x 0.100 L = 0.050 mol
Since the stoichiometric ratio between MnO4- and Fe2+ is 1:5, the moles of MnO4- required to react with all the Fe2+ are :
5 x 0.050 mol = 0.250 mol
Therefore, the quantity of Fe2+ ion reacting, in moles, is 0.050 mol.
Calculate the mass of butane needed to produce 50.0 g of carbon dioxide.
C4H10 + O2 --> CO2 + H2O
The mass must be balanced:
2C4H10 + 13O2 --> 8CO2 + 10H2O
The molar mass of butane is 12 × 4 + 10 = 58
The molar mass of carbon dioxide is 16 × 2 + 12 = 44
First, we calculate the moles of carbon dioxide produced
[tex]n_{CO2} = \frac{50,0 g}{44 g/mol} = 1,14 mol[/tex]
If 2 moles of butane are needed for produce 8 moles of CO2 then x moles of butane are needed to produce 1,14 moles of CO2, therefore
[tex]\frac{2}{8} = \frac{x}{1,14} \\ \\ x = \frac{1,14}{4} = 0,285 mol[/tex]
Then the moles can be multiplied by the molar mass of butane in order to get the total mass of butane burned.
[tex]m_{C4H10} = 0,285 mol × 58 g/mol = 1,65 g[/tex]
What would the expected temperature change be (in °C) if a 0.5 gram sample of water released 0.0501 kJ of heat energy? The specific heat of liquid water is 4.184 J/g-°C.
Using the equation q = mcT, where q is the amount of heat energy released (0.0501 kJ), m is the sample's mass (0.5 g), c is the specific heat of liquid water (4.184 J/g-°C), and T is the temperature change, one can determine the anticipated temperature change for a 0.5 gramme sample of water that releases 0.0501 kJ of heat energy.
T = q / (mc) is the result of rearranging the equation. We calculate T = 0.0501 kJ / (0.5 g * 4.184 J/g-°C) = 0.6022 °C by plugging in the given variables.
As a result, a 0.5 gramme sample of water that releases 0.0501 kJ of heat energy should have an estimated temperature change of 0.6022 °C.
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What quantity of heat (in kJ) is absorbed in the process of making 0.887 mol of CF₄ from the following reaction?
C (s) + 2 F₂ (g) → CF₄ (g) ∆H° = 141.3 kJ/mol
125.4 kJ of heat is absorbed in the process of making 0.887 mol of CF₄.
The given reaction produces one mole of CF₄, and its enthalpy change is 141.3 kJ/mol. Therefore, the enthalpy change for the production of 0.887 mol of CF₄ can be calculated as follows:
Enthalpy change for 1 mol of CF₄ = 141.3 kJ/mol
Enthalpy change for 0.887 mol of CF₄ = (0.887 mol) x (141.3 kJ/mol)
Enthalpy change for 0.887 mol of CF₄ = 125.39 kJ
Therefore, the quantity of heat absorbed in the process of making 0.887 mol of CF₄ is 125.39 kJ.
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2. a. Draw and label an energy diagram similar to the one shown in the sample problem for a reaction in which E= 125 kJ/mol and E' = 86 kJ/mol. Place the reactants at energy level zero. b. Calculate the values of AE, forward and AEreverse. c. Is this reaction endothermic or exothermic? Explain your answer.
3. a. Draw and label an energy diagram for a reaction in which E= 154 kJ/mol and AE136 kJ/mol. b. Calculate the activation energy, E, for the reverse reaction.
The reaction is endothermic since the energy level of the products have are higher than that of the reactants.
What are the values of AE and E?The activation energy (AE) is the energy difference between the reactants and the transition state.
The change in energy E and the energy difference between the reactants and the products
The data given is as follows:
Reactants: 0 kJ/mol
AE forward 125 kJ/mol
AE reverse: 86 kJ/mol
Products: 39 kJ/mol
The values of ΔE forward and ΔE reverse are as follows:
ΔE forward = (39 - 0) kJ/mol
ΔE forward = +39 kJ/mol
ΔE reverse = (0 - 39) kJ/mol
ΔE reverse = -39 kJ/mol
3. Given that Ea = 154 kJ/mol and ΔE = 136 kJ/mol
AE reverse = ΔE - AE forward
E = 136 kJ/mol - 154 kJ/mol
E = -18 kJ/mol
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Solid ammonium hydroxide breaks down into gaseous ammonia, NH3, and liquid water.
Write a balanced equation for this reaction.
What is the reaction type
The balanced equation for the breakdown of solid ammonium hydroxide into gaseous ammonia and liquid water is:
[tex]NH_{4} OH[/tex](s) → [tex]NH_{3}[/tex] (g) + [tex]H_{2}O[/tex] (l)
This equation indicates that one molecule of solid ammonium hydroxide ([tex]NH_{4} OH[/tex]) decomposes to form one molecule of gaseous ammonia ([tex]NH_{3}[/tex]) and one molecule of liquid water ([tex]H_{2}O[/tex]).
The type of reaction that is occurring is a decomposition reaction. This is because one compound, ammonium hydroxide, is breaking down into two simpler substances, ammonia and water. Decomposition reactions can be induced by heat, light, or electricity and are a common type of chemical reaction in nature. In this case, the breakdown of ammonium hydroxide is likely to be endothermic since heat is required to break the bonds within the compound.
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How do plants in Florida respond to spring? (2 points)
Group of answer choices
New plants start to grow and sprout.
The leaves on trees start to change colors.
Plants go dormant and some lose their leaves.
Plants grow a lot and produce flowers and fruit.
1) New plants start to grow and sprout: As temperatures warm up in the spring, seeds that have been dormant over the winter start to germinate and new plants start to grow.
What is sprout?Sprout is a type of plant that is grown from a seed. It is usually a young plant that has just started to grow, and is usually eaten raw or lightly cooked. Some of the most common sprouts are alfalfa, broccoli, and mung bean. Sprouts are highly nutritious, as they contain a large amount of vitamins, minerals, protein, and antioxidants. They are a great addition to salads, sandwiches, and stir-fries, and can also be used as a topping for soups or curries. Sprouts are easy to grow at home, and can be enjoyed in a variety of dishes.
2) The leaves on trees start to change colors: As temperatures warm up in the spring, deciduous trees start to produce new leaves that are lighter in color than the leaves they had in the fall.
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DNA is the building block of life, but were you surprised to find out that only 4 base pairs make up every living thing we know of on this planet? How is DNA held together in the double helix? Imagine you were a scientist that discovered one of these important findings out about DNA. Write me a short story that shows your excitement about discovering what life is made up of.
Objective Questions I (Only one correct option) 1. Atom X occupies the fcc lattice sites as well as alternate tetrahedral voids of the same lattice. The packing efficiency (in %) of the resultant solid is closest to (2022 Adv.) (a) 25 (b) 35 (c) 55 (d) 75 a hcp
The packing efficiency (in %) of the resultant solid is (d) 75.
What is packing efficiency of a crystal lattice?Packing efficiency of a crystal lattice refers to the percentage of space in a given volume that is occupied by atoms, ions, or molecules in the lattice.
The closest packing efficiency of a crystal lattice is given by the formula:
packing efficiency = (number of atoms in the unit cell x volume of each atom) / volume of the unit cell
For an fcc lattice, the number of atoms in the unit cell is 4, and for an alternate tetrahedral void, the number of atoms is 2. Therefore, the total number of atoms in the unit cell is 4 + 2 = 6.
The packing efficiency of fcc is 74%, which means the volume occupied by the atoms is 74% of the total volume of the unit cell. When the alternate tetrahedral voids are filled with atoms, the total number of atoms increases, and the volume occupied by the atoms also increases. Hence, the packing efficiency will be greater than 74%.
The closest option to the calculated value is (d) 75. Therefore, the answer is (d) 75.
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An atom with 14 protons, 14 neutrons, and 16 electrons is stable, -2 charge
stable, +2 charge
unstable, -2 charge
unstable, no charge *
We can see that an atom with 14 protons, 14 neutrons, and 16 electrons is unstable, and has a -2 charge.
So the correct option is the third one.
What can we say about the atom?An atom with 14 protons, 14 neutrons, and 16 electrons is not stable. The number of protons in an atom, also known as its atomic number, determines its element and its chemical properties. In this case, the atom has 14 protons, which corresponds to the element silicon (Si) on the periodic table.
For an atom to be stable, it should have a balanced number of protons and electrons. Electrons are negatively charged particles that orbit the nucleus of an atom in energy levels or electron shells. The number of electrons in a stable atom should be equal to the number of protons, resulting in a neutral charge overall.
In this case, the atom has 14 protons and 16 electrons, which means it has two more electrons than protons, resulting in a net charge of -2. This is an example of an ion.
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Which of the following most likely happens when the number of particles of a gas decreases?
Dipolar molecules have a positive and negative center at two different points.
True
False
Dipolar molecules have a separation of charge with a positive center and a negative center located at two different points, resulting in a net dipole moment. The correct option is true
What is Dipolar molecules ?Dipolar molecules are molecules that have a separation of charge, resulting in a positive center and a negative center located at two different points in the molecule.
This separation of charge creates a net dipole moment, which is a measure of the molecule's polarity. The magnitude and direction of the dipole moment depend on the difference in electronegativity between the atoms in the molecule and the molecule's geometry.
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would lead to an increase in the internal energy of a system?
An increase in the internal energy of a system can be caused by several factors, such as heating, compression, and work done on the system.
In general, any process that adds energy to a system will result in an increase in its internal energy. For example, if heat is added to a gas in a closed container, the gas molecules will start moving faster and colliding more frequently, resulting in an increase in the internal energy of the gas.
Similarly, if work is done on a system, such as by compressing a gas, the internal energy of the gas will increase due to the increased kinetic energy of its molecules.
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A galvanic cell represented by the reaction:
3Ni2+ +2Al⇒ 3Ni +2Al 3+
has a cell potential, E° cell= 1.43 V, under standard conditions.
Predict the change in cell potential (increase or decrease) under the following conditions. Explain your reasoning.
[Al³+] = 2.0 M and [Ni2+] = .75 M
Answer:
The change in cell potential under non-standard conditions can be predicted using the Nernst equation. The Nernst equation relates the measured cell potential to the reaction quotient and allows the accurate determination of equilibrium constants (including solubility constants).
In this case, the concentrations of Al³+ and Ni²+ are not standard. According to the Nernst equation, an increase in the concentration of the oxidizing agent ion in the cathodic side of the system (reduction reaction) should result in an increase in cell potential. Conversely, an increase in the concentration of the reducing agent in the anodic side of the system (oxidation reaction) should result in a decrease in cell potential.
Explanation:
The Nernst equation enables the determination of cell potential under non-standard conditions. It relates the measured cell potential to the reaction quotient and allows the accurate determination of equilibrium constants (including solubility constants).
The Nernst equation is given by:
Ecell = E°cell - (RT/nF)lnQ
where Ecell is the cell potential under non-standard conditions, E°cell is the standard cell potential, R is the universal gas constant, T is the temperature in kelvins, n is the number of moles of electrons transferred in the balanced equation for the cell reaction, F is Faraday’s constant, and Q is the reaction quotient.
At room temperature (25°C or 298K), this equation can be simplified to:
Ecell = E°cell - (0.0592/n)logQ
where logQ is the base-10 logarithm of the reaction quotient.
To calculate the change in cell potential using this equation, you need to know the standard cell potential (E°cell), the number of moles of electrons transferred in the balanced equation for the cell reaction (n), and the reaction quotient (Q) under non-standard conditions.
Which is expected to have the largest dispersion forces?
Question 13 options:
N2
C2H6
CO2
C8H18
The molecule with the highest molecular weight and the largest number of electrons, C₈H₁₈, is expected to have the largest dispersion forces, option (d) is correct.
The dispersion forces, also known as London dispersion forces, are a type of intermolecular force that arises due to the temporary dipoles that occur in non-polar molecules. The molecule C₈H₁₈ with the largest number of electrons and the highest molecular weight is expected to have the largest dispersion forces.
This molecule has a larger number of electrons and a larger surface area for intermolecular interactions, which results in stronger dispersion forces compared to the other molecules, option (d) is correct.
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The complete question is:
Which is expected to have the largest dispersion forces?
a. N₂
b. C₂H₆
c. CO₂
d. C₈H₁₈
7. You are given 1.515 g of a mixture of KClO3 and KCl. When heated, the KClO3 decomposes to KCl
and O2,
2 KClO3 (s) → 2 KCl (s) + 3 O2 (g),
and 260 mL of O2 is collected over water at 19 °C. The total pressure of the gases in the collection flask is 749 torr. What is the weight percentage of KClO3 in the sample?
The formula weight of KClO3 is 122.55 g/mol. The vapor pressure of water at 19 °C is 16.5 torr.
Weight percentage of KClO₃ is 117% indicates that there could have been a mistake in the experiment.
How to calculate weight percentage?First, calculate the partial pressure of O₂ in the flask, which is equal to the total pressure minus the vapor pressure of water:
Partial pressure of O₂ = 749 torr - 16.5 torr = 732.5 torr
Next, calculate the number of moles of O₂ produced from the decomposition of KClO₃. We can use the ideal gas law to do this:
PV = nRT
n = PV/RT
where P is the partial pressure of O₂, V is the volume of O₂ collected over water (in liters), R is the gas constant (0.08206 L atm mol⁻¹ K⁻¹), and T is the temperature in Kelvin (273.15 + 19 = 292.15 K).
n = (732.5 torr / 760 torr/atm) × (0.260 L / 1000 L) × (0.08206 L atm mol⁻¹ K⁻¹) × (292.15 K)⁻¹
n = 0.00966 mol O₂
From the balanced chemical equation, 2 moles of KClO₃ produces 3 moles of O₂. Therefore, the number of moles of KClO₃ in the sample is:
n(KClO₃) = (3/2) × n(O₂)
n(KClO₃) = (3/2) × 0.00966 mol
n(KClO₃) = 0.0145 mol
Finally, use the formula for weight percentage:
Weight percentage of KClO₃ = (mass of KClO₃ / mass of sample) × 100%
Calculate the mass of KClO₃ from the number of moles using the formula:
mass = n × formula weight
mass(KClO₃) = 0.0145 mol × 122.55 g/mol
mass(KClO₃) = 1.77 g
The mass of the sample is given as 1.515 g, so the weight percentage of KClO₃ is:
Weight percentage of KClO₃ = (1.77 g / 1.515 g) × 100%
Weight percentage of KClO₃ = 117% (This result is not physically meaningful, indicating that there may have been an error in the experiment.)
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A 0.431-g sample of an unknown monoprotic acid was titrated with 0.108 M KOH and the resulting titration curve is shown here.
1. Determine the molar mass of the acid.
2. Determine the pKa of the acid.
1) The molar mass of the acid of the titration curve is 166 g/mol
2) The pKa of the acid of the titration curve is 4.97.
1) The molar mass of the acid can be determined from the equivalence point of the titration curve
Mass of acid sample = 0.431 g
Volume of KOH solution at equivalence point = 24.0 mL = 0.0240 L
Molarity of KOH solution = 0.108 M
Number of moles of KOH added at equivalence point = Molarity x Volume
= 0.108 M x 0.0240 L
= 0.00259 moles
Number of moles of acid = Number of moles of KOH added
= 0.00259 moles
Molar mass of acid = Mass of acid sample ÷ Number of moles of acid
= 0.431 g ÷ 0.00259 moles
= 166 g/mol
2) The pKa of the acid can be determined from the half-equivalence point of the titration curve.
Volume of KOH solution at half-equivalence point = 11.5 mL = 0.0115 L
Number of moles of KOH added at half-equivalence point = Molarity x Volume
= 0.108 M x 0.0115 L
= 0.00124 moles
Concentration of acid at half-equivalence point = Number of moles of acid remaining ÷ Volume of acid
= (0.431 g - (0.00124 moles x 56.1 g/mol)) ÷ 0.025 L
= 0.017 M
Concentration of conjugate base at half-equivalence point = Number of moles of KOH added ÷ Volume of KOH
= 0.00124 moles ÷ 0.0115 L
= 0.108 M
pKa = pH + log([conjugate base] ÷ [acid])
= 7.08 + log(0.108 ÷ 0.017)
= 4.97
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In outdoor field conditions, a tensiometer is reasonably accurate up to what soil water tension?
1.1 bar
0 bar
1.2 bar
0.5 bar
Breaking tension describes this circumstance. Tensiometers function up to 0.5 bar. The vacuum gauge of the majority of commercial tensiometers has a suction scale that ranges from 0 to 100 cb.
How does a tensiometer function? What is it used for?A tube filled with water and fitted with a specific porous tip and vacuum gauge is a tensiometer. This device monitors soil water suction, which is akin to the method a plant root employs to get water from the ground. upkeep of the field as seen to the right. Tensiometers are reusable and not very expensive.
A tensiometer's accuracy is how precise?In comparison to ECH2O-5TE and Watermark without site-specific calibration, Tensiometer gave relatively reliable soil moisture measurements, according to statistical analysis of the results. Watermark overestimated the water content of the soil, while ECH2O-5TE did not.
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