Energy, potential energy, is stored in the covalent bonds holding atoms together in the form of molecules. This is often called chemical energy. Except at absolute zero (the coldest temperature it is possible to reach), all molecules move.
Answer:
Chemical energy
Explanation:
Energy, potential energy, is stored in covalent bonds holding atoms together in the form of molecules
What does iron (ll) indicate that a compound contains?
iron ions with a ll+ charge
iron ions with a ll+ charge
iron ions with 2+ charge
iron ions with 2+ charge
iron ions with 2- chaarge
iron ions with 2- chaarge
two types of iron ions
Answer:
iron ions with a 2+ charge
Bena thinks that dissolving more salt in water causes the mixture’s freezing temperature to change.
FAST PLEASE
Which is the best type of scientific investigation for Bena to use to study this?
an experimental investigation, because it can provide the most data
a comparative investigation, because it uses a wide range of variables
an experimental investigation, because it allows for the control of variables
a comparative investigation, because it would take the least amount of time
Answer:
The right option is; an experimental investigation, because it allows for the control of variables.
Explanation:
(-7b + 8c) - (12a + 14) + (5a + 5b) =
Given problem;
(-7b + 8c) - (12a + 14) + (5a + 5b) = ?
To this problem, we open the brackets, collect like terms and factor them.
The order of operation, PEMDAS must be strictly adhered to;
P = Parentheses
E = Exponent
M = multiplication
D = Division
A = Addition
S = Subtraction
(-7b + 8c) - (12a + 14) + (5a + 5b);
Open the parentheses;
Note; + x + = +
+ x - = -
- x - = +
- x + = -
So,
= -7b + 8c -12a - 14 + 5a + 5b
Collect like terms;
= 5a -12a + 5b - 7b + 8c -14
= -7a - 2b + 8c -14
The solution is -7a - 2b + 8c -14
8. What is the mass of copper in a sample of copper(I) chloride weighing 6.93 g ?*
Answer:
4.5g
Explanation:
Given parameters:
Mass of copper(i)chloride = 6.93g
Unknown:
Mass of copper = ?
Solution:
Formula of the compound = CuCl
atomic mass of Cu = 63.6g/mol, atomic mass of Cl = 35.5g/mol
Molecular mass = 63.6 + 35.5 = 99.1g/mol
So,
The mass of copper = [tex]\frac{63.6}{99.1}[/tex] x 6.93 = 4.5g
Which sentence describes all atoms of one element?
1.) they have the same number of isotopes?
2.) they have the same number of neutrons?
3.) they have the same number of electrons?
4.) they have the same number of protons?
Answer:
4. they have the same number of protons
Explanation:
while all the other particles and attributes can be changed, protons cannot.
question the substances in a beaker are at room temperature before a chemical reaction takes place. what do you know if you touch a beaker during the chemical reaction and it feels cold?
When substances in a beaker are at room temperature before a chemical reaction takes place, the beaker will usually feel neutral or at the same temperature as the surroundings. If you touch a beaker during the chemical reaction and it feels cold, it indicates an endothermic reaction.
What is an endothermic reaction? An endothermic reaction is a type of chemical reaction that absorbs heat energy from its surroundings. Endothermic reactions require an external energy source to drive the reaction. During the reaction, energy is absorbed, causing the surrounding environment to feel cooler than before. This causes the temperature of the beaker to decrease, resulting in a cold sensation when touched. This type of reaction is characterized by a positive change in enthalpy (ΔH>0). What is an exothermic reaction? Exothermic reactions, on the other hand, release energy into the surroundings.
These reactions occur spontaneously, and heat is released as a result. The temperature of the beaker increases, causing it to feel warm to the touch. The reaction has a negative change in enthalpy (ΔH<0). ConclusionIn conclusion, if the beaker feels cold during a chemical reaction, it is a good indication that an endothermic reaction is taking place, and energy is being absorbed from the surroundings. If the beaker feels warm, it is an exothermic reaction, and energy is being released into the surroundings.
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why is it important to align the cuvet in the sample holder the same way each time? cuvets must be aligned in the sample holder the same way each time because only two sides are transparent, so if it is placed incorrectly in the holder, then it will block the light and lead to an incorrect absorbance. cuvets must be aligned in the sample holder the same way each time in order to minimize any effect that imperfections in the glass will have on your results. both of the above are correct.
Aligning the cuvet in the sample hold measurement er the same way each time is important to ensure that the optical windows are correctly positioned in the light path, allowing accurate of absorbance.
Both of the given statements are correct, and aligning the cuvet in the sample holder the same way each time is indeed important for accurate measurements in spectrophotometry.
1. Only two sides are transparent: Cuvets, or cuvette cells, are typically rectangular or square-shaped containers made of glass or plastic. They have two transparent sides, known as optical windows, through which light passes. The other sides are opaque. If the cuvet is placed incorrectly in the sample holder, such that the optical windows are not aligned with the light path, it will block or obstruct the passage of light, resulting in an incorrect measurement of absorbance. Consistent alignment ensures that the light passes through the cuvet properly and allows accurate determination of the absorbance of the sample.
2. Minimize the effect of imperfections: The glass or plastic material used to make cuvets may have minor imperfections, such as scratches or impurities. These imperfections can cause variations in the transmission of light through the cuvet. By aligning the cuvet in the same way each time, any effects caused by the imperfections can be minimized or averaged out, leading to more reliable and consistent results. In this way, consistent alignment helps to reduce potential errors or inconsistencies in the measurements caused by the cuvet itself.
In summary, aligning the cuvet in the sample holder the same way each time is important to ensure that the optical windows are correctly positioned in the light path, allowing accurate measurement of absorbance. Additionally, consistent alignment helps to minimize any effects caused by imperfections in the cuvet material, resulting in more reliable and consistent measurements.
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Even if an object is sitting perfectly still and not moving, the atoms and molecules that the object is made of still have kinetic energy due to their constant motion
true or false?
Answer:
True
Explanation:
the atoms never stop moving, so the answer is true
For the titration of 40.0 mL of 0.250 M acetic acid with 0.200 M sodium hydroxide, determine the pH when:
(a) 40.0 mL of base has been added
(b) 50.0 mL of base has been added
(c) 60.0 mL of base has been added
a) pH is approximately 13.10. b) pH will be slightly above 7, indicating a basic solution. c) pH will be higher than the pH at the equivalence point, further indicating a basic solution.
(a) When 40.0 mL of base (0.200 M sodium hydroxide) has been added to the 40.0 mL of 0.250 M acetic acid, we have a neutralization reaction between the acid and base. Acetic acid (CH3COOH) is a weak acid, and sodium hydroxide (NaOH) is a strong base.
To calculate the pH at this point, we need to determine the moles of acid and base present and determine the excess or deficit of either. Since acetic acid and sodium hydroxide react in a 1:1 ratio, the moles of acid are equal to the moles of base added.
Using the formula:
Moles = Volume (L) x Concentration (M)
The moles of acetic acid are:
Moles of acetic acid = 0.040 L x 0.250 mol/L = 0.010 mol
Since the moles of acetic acid and sodium hydroxide are equal, we have 0.010 mol of sodium hydroxide in 0.040 L.
To calculate the concentration of hydroxide ions, we divide the moles of sodium hydroxide by the total volume (80.0 mL or 0.080 L):
Concentration of OH- = 0.010 mol / 0.080 L = 0.125 M
Using the equation for the dissociation of water (Kw = [H+][OH-]), we can calculate the concentration of H+ ions:
Kw = [H+][OH-]
1.0 x 10^-14 = [H+][0.125]
[H+] = 8.0 x 10^-14 M
Taking the negative logarithm of the concentration of H+ ions gives us the pH:
pH = -log[H+] = -log(8.0 x 10^-14) ≈ 13.10
(b) When 50.0 mL of base has been added, the calculation follows a similar process. The moles of acetic acid remain the same (0.010 mol), but the moles of sodium hydroxide increase to 0.0125 mol due to the additional volume (50.0 mL or 0.050 L) of base added.
Using the formula:
Moles = Volume (L) x Concentration (M)
The moles of sodium hydroxide are:
Moles of sodium hydroxide = 0.050 L x 0.200 mol/L = 0.010 mol
Since the moles of acetic acid and sodium hydroxide are equal (0.010 mol), we have reached the equivalence point of the titration. At the equivalence point, all the acetic acid has been neutralized by the sodium hydroxide, resulting in a solution of sodium acetate (CH3COONa) and water.
The pH at the equivalence point depends on the nature of the resulting salt, sodium acetate. Sodium acetate is the conjugate base of a weak acid, acetic acid, and is a weak base. The hydrolysis of sodium acetate in water leads to the formation of hydroxide ions, resulting in a slightly basic solution.
Therefore, at the equivalence point, the pH will be slightly above 7, indicating a basic solution.
(c) When 60.0 mL of base has been added, the calculation follows the same process as in part (b). At this point, the moles of sodium hydroxide are greater than the moles of acetic acid.
Using the formula:
Moles = Volume (L) x Concentration (M)
The moles of sodium hydroxide are:
Moles of sodium hydroxide = 0.060 L x 0.200 mol/L = 0.012 mol
Since the moles of sodium hydroxide (0.012 mol) are greater than the moles of acetic acid (0.010 mol), there is an excess of base present in the solution.
The excess base, sodium hydroxide, will result in a basic solution. The pH will be higher than at the equivalence point, indicating a stronger basic character.
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which of the following aqueous solutions when mixed produces a precipitate? question options: a) nh4no3(aq) and bacl2(aq) b) li2so4(aq) and cabr2(aq) c) ki(aq) and na2co3(aq) d) cscl and (nh4)3po4 e) naoh and hcl g
When aqueous solutions of NH4NO3 and BaCl2 are mixed, they don't produce a precipitate.
The mixing of an aqueous solution of NH4NO3 and BaCl2 will not result in a precipitate being formed. The reaction that takes place in the aqueous solution is NH4NO3 + BaCl2 → Ba(NO3)2 + 2NH4Cl. The balanced equation shows that the products of the reaction are Ba(NO3)2 and NH4Cl, both of which are soluble in water. As a result, there will be no formation of a precipitate when the two solutions are mixed. Aqueous solutions of NH4NO3 and BaCl2 will not produce a precipitate when mixed.
There will be no visible change in the appearance of the mixture as the products formed are soluble in water.
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the order for a 33-kg dog is 5 micrograms/kg/min dobutmine. a 12.5 mg/ml solution of dobutamine is available. the dobutamine will be run at a rate of 20 ml/hr and will be added to a 500-ml bag of fluid. what quantity (ml) will you add to the bag?
Based on the given parameters, adding 0.5 mL of the 12.5 mg/mL dobutamine solution to the 500 mL bag of fluid will achieve the desired concentration and infusion rate for the 33 kg dog.
To determine the quantity of dobutamine to add to the 500 mL bag of fluid, we need to calculate the total amount of dobutamine required based on the dog's weight and the infusion rate.
First, we convert the weight of the dog from kilograms to grams:
33 kg × 1000 g/kg = 33000 g
Next, we calculate the total amount of dobutamine required per minute:
5 micrograms/kg/min × 33 kg = 165 micrograms/min
Since the concentration of the dobutamine solution is given in mg/mL, we need to convert micrograms to milligrams:
165 micrograms/min × 1 mg/1000 micrograms = 0.165 mg/min
Now, we convert the infusion rate from milliliters per hour to milliliters per minute:
20 mL/hr ÷ 60 min/hr = 0.33 mL/min
Finally, we can calculate the quantity of dobutamine to add to the bag:
0.165 mg/min ÷ 0.33 mL/min = 0.5 mg/mL
Therefore, you would add 0.5 mL of the 12.5 mg/mL dobutamine solution to the 500 mL bag of fluid.
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1.) Draw a diagram of the chemical structure of oil-based paint.
With an explanation
The specific composition of oil-based paint can vary depending on the brand and formulation.
Oil-based paint typically consists of three main components: pigments, binders, and solvents. The pigments provide the color and opacity to the paint, while the binders are responsible for holding the pigment particles together and adhering them to the painted surface. The solvents help to adjust the paint's consistency and facilitate its application.
The binder in oil-based paint is commonly a natural oil, such as linseed oil or tung oil. These oils are composed of fatty acid molecules, which contain a long carbon chain with a carboxyl group (-COOH) at one end. The carboxyl group can react with oxygen in a process called oxidation, forming a cross-linked network of molecules that harden over time, creating a durable paint film.
The solvents in oil-based paint are typically organic compounds, such as mineral spirits or turpentine. These solvents dissolve the binder and pigments, making the paint flowable and easy to apply. As the solvent evaporates, the paint gradually dries and the binder undergoes the oxidation process, resulting in the formation of a solid paint film.
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Calculate the number of moles in the following: 2.8 X 10^24 atoms of Cl2
Answer:
The answer is 4.65 molesExplanation:
To find the number of moles given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
N = 2.8 × 10²⁴ atoms of Cl2
So we have
[tex]n = \frac{2.8 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 4.65116279069...[/tex]
We have the final answer as
4.65 molesHope this helps you
Most thermal conductors are made of which material?
Answer:
Most are made of copper.
Explanation:
Answer: The answer is metal
Explanation:
I took the test:) np!
If 150 grams of water is to be heated from 15.0°C to 100°C to make a cup of tea, how much heat must be added? The specific heat of water is 4.18 J/g°C
Answer:
The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.
Explanation:
The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.
which of the compounds shown, all with the molecular formula c {9}*h {18}*o {2} is consistent with the nmr and ^ 13 c nmr spectra given ?
The molecular formula of all the compounds is C9H18O2. The spectral data helps to differentiate the compounds. The spectral data reveals the carbon environment of each atom of the molecule.
The structure of a molecule can be predicted by analyzing NMR spectra and the type of carbon atom in the molecule by analyzing 13C NMR spectra.The NMR spectrum for Compound B shows a peak at δ 2.2, indicating the presence of an -CH2- group. In the 13C NMR spectrum for Compound B, a peak appears at δ 30.3, indicating the presence of a carbon atom with two hydrogens attached. In the molecule of Compound B, the only carbon atom with two hydrogens attached is the one that is part of the -CH2- group. As a result, Compound B is made up of a straight-chain carbon chain with a terminal carboxyl group and a single methyl group attached to the 3rd carbon atom.The NMR spectrum for Compound A shows peaks at δ 1.6, 2.3, and 2.8, indicating the presence of an -CH3 group, a -CH2- group, and a -CH- group, respectively. In the 13C NMR spectrum for Compound A, peaks appear at δ 15.3, 22.8, and 28.5, indicating the presence of three carbon atoms with one hydrogen each. In the molecule of Compound A, the carbon atoms with one hydrogen each are the three carbon atoms that make up the -CH3 group, the -CH2- group, and the -CH- group. As a result, Compound A is made up of a branched carbon chain with a terminal carboxyl group and a single methyl group attached to the 4th carbon atom.
Compound A is made up of a branched carbon chain with a terminal carboxyl group and a single methyl group attached to the 4th carbon atom. Compound B is made up of a straight-chain carbon chain with a terminal carboxyl group and a single methyl group attached to the 3rd carbon atom. Therefore, the NMR and 13C NMR spectra are consistent with Compounds A and B, respectively, and their molecular formulas are C9H18O2.
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2. What contribution did these scientists make to atomic models of the atom?
a. Dalton-1st atomic structure
b.Thomson-electron
c.Rutherford-nucleus’s
a tank at is filled with of dinitrogen difluoride gas and of boron trifluoride gas. you can assume both gases behave as ideal gases under these conditions. calculate the mole fraction of each gas. round each of your answers to significant digits.
To calculate the mole fraction of each gas, we need to first calculate the total number of moles of the gas in the tank using the ideal gas law, PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the universal gas constant, and T is the temperature.
We can rearrange this equation to solve for n, which gives us:n = PV/RTWhere:P = pressure = 1 atmV = volume = not givenR = universal gas constant = 0.08206 L·atm/(mol·K)T = temperature = not givenSince we don't have information about the volume or temperature of the gas in the tank, we cannot calculate the total number of moles directly. However, we can use the mole fraction to find the number of moles of each gas present in the tank.
We can find the mole fraction of dinitrogen difluoride (N2F2) by dividing the number of moles of N2F2 by the total number of moles of gas present in the tank:x(N2F2) = n(N2F2)/n(total).
Similarly, we can find the mole fraction of boron trifluoride (BF3) by dividing the number of moles of BF3 by the total number of moles of gas present in the tank:x(BF3) = n(BF3)/n(total)To find the mole fraction of each gas, we need to know the total number of moles of gas present in the tank. Without the volume or temperature of the gas in the tank, we cannot calculate the total number of moles or the mole fraction of each gas.
Without the volume or temperature of the gas in the tank, we cannot calculate the mole fraction of each gas.
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what is the volume in milliliter(ml) of 250 cm ^3 beaker
Answer:
[tex]\boxed {\tt 250 \ mL}[/tex]
Explanation:
First, let's remember that 1 cubic centimeter is equal to 1 milliliter.
1 cm³ = 1 mLWe have a beaker that is 250 cubic centimeters. Since 1 cubic centimeter is equal to 1 milliliter,
250 cm³= 250 mLThe volume in a 250 cm³ beaker is 250 milliliters.
Answer:
a cubic centimeter is the same as a millimeter, so it would just be 250ml
A doctor sees 10 patients in one day. The following is a list of their ailments. Patient 1 - seasonal allergies Patient 2 - common cold Patient 3 - sinus infection Patient 4 - seasonal allergies Patient 5 - chronic heartburn Patient 6 - seasonal allergies Patient 7 - migraines Patient 8 - back pain Patient 9 - broken wrist Patient 10 - chronic heartburn Which of the ailments listed had a frequency of three?
Answer:
seasonal allergies
Explanation:
The ailments listed had a frequency of three is seasonal allergies. Thus, 1st is the correct option.
What is seasonal allergy?Allergy is an infection caused due to entrance of some unwanted allergy causing components in body and they cause sneezing, coughing, ittiching and other symptoms that make trouble for the patient.
Seasonal allergy is the form of allergy that occurs in a particular season and they affect the individual in a particular season only.
Allergic substance can be anything it means allergy is experienced by any substance like some people are allergic from wheat, some are allergic from dust and likewise there are different allergy causing substances present.
In case of allergy, anti allergic medicines are given to the patient to avoid serious condition.
Therefore, the ailments listed had a frequency of three is seasonal allergies. Thus, 1st is the correct option.
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HW 2 - Matter Day 1
1.
Classify the following as Matter or Not matter
a. Calculator
b. Heat
C. Air
d. Wind
e. Water
f. Ice
g. Electricity
1. If the density of mercury is 13.6 g/cm3, what will be the volume of 300g
of mercury?
Answer:
Volume (V) = 2.2058823529412E-5 cubic meter
Explanation:
Round if nessesarry
v = 0.3kg / 13600
v = 2.2x10^-5 m^3
which electron in sulfur is most shielded from nuclear charge? a. an electron in the 1s orbital b. an electron in a 2p orbital c. an electron in a 3p orbital d. none of the above (all of these electrons are equally shielded from nuclear charge.)
The electron in sulfur that is most shielded from nuclear charge is an electron in a 3p orbital. As we move away from the nucleus, the energy level of the atom's electron orbitals increases, resulting in increased shielding from the nuclear charge. As a result, the 3p orbital electron is the most shielded from the nuclear charge in sulfur.
Sulfur is a nonmetal that is located in the periodic table's third row. It is represented by the symbol "S," and its atomic number is 16. Electrons are located in orbitals, or shells, around the nucleus of an atom. These orbitals have varying degrees of shielding from the atomic nucleus, which is influenced by the number of electrons in other orbitals and the distance from the nucleus. The 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and 5s orbitals are the electron orbitals in a sulfur atom.
Only three orbitals are considered for the electron shielding inquiry, which are the 1s, 2p, and 3p orbitals. The 1s orbital electron is closer to the nucleus than the 2p and 3p orbital electrons, implying that it is less shielded from the nuclear charge. Electrons in the 2p and 3p orbitals are farther from the nucleus than electrons in the 1s orbital, indicating that they are more shielded from the nuclear charge. As a result, the electron in a 3p orbital in sulfur is the most shielded from nuclear charge.
In sulfur, the electron in a 3p orbital is the most shielded from the nuclear charge since the 3p orbital electron is farther from the nucleus than the 1s orbital electron.
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a tank at is filled with of dinitrogen difluoride gas and of boron trifluoride gas. you can assume both gases behave as ideal gases under these conditions. calculate the mole fraction of each gas. round each of your answers to significant digits.
the mole fraction of dinitrogen difluoride (N2F2) is approximately 0.584, and the mole fraction of boron trifluoride (BF3) is approximately 0.416.
To calculate the mole fraction of each gas in the tank, we need to determine the number of moles of each gas and then calculate the mole fraction using the following formula:
Mole fraction = Moles of a gas / Total moles of all gases
Given:
Amount of dinitrogen difluoride gas (N2F2) = 0.045 mol
Amount of boron trifluoride gas (BF3) = 0.032 mol
Total moles of all gases = 0.045 mol + 0.032 mol = 0.077 mol
Mole fraction of dinitrogen difluoride (N2F2):
Mole fraction of N2F2 = 0.045 mol / 0.077 mol = 0.584 (rounded to three significant digits)
Mole fraction of boron trifluoride (BF3):
Mole fraction of BF3 = 0.032 mol / 0.077 mol = 0.416 (rounded to three significant digits)
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The type(s) of intermolecular forces exhibited by hydrogen bromide molecules, HBr, is/are ________.
The type(s) of intermolecular forces exhibited by hydrogen bromide molecules, HBr, are dipole-dipole interactions and London dispersion forces.
Hydrogen bromide (HBr) is a polar molecule due to the difference in electronegativity between hydrogen and bromine atoms. Bromine is more electronegative than hydrogen, resulting in a partial negative charge on the bromine atom and a partial positive charge on the hydrogen atom. This creates a permanent dipole moment in the HBr molecule. Dipole-dipole interactions occur between the positive end of one molecule (the hydrogen atom) and the negative end of another molecule (the bromine atom). These intermolecular forces are relatively stronger than the London dispersion forces.
In addition to dipole-dipole interactions, hydrogen bromide molecules also experience London dispersion forces. These forces arise due to temporary fluctuations in electron distribution within molecules. Even though HBr is a polar molecule, it can still exhibit London dispersion forces since all molecules, regardless of polarity, have electrons that are constantly in motion. These temporary fluctuations in electron distribution create instantaneous dipoles, leading to attractive forces between neighboring molecules.
Overall, the intermolecular forces in hydrogen bromide (HBr) include both dipole-dipole interactions and London dispersion forces. These forces play a crucial role in determining the physical properties and behavior of HBr, such as boiling point, solubility, and viscosity.
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what minimum volume of 0.282 m potassium iodide solution is required to completely precipitate all of the lead in 165.0 ml of a 0.150 m lead (ii) nitrate solution? what minimum volume of 0.282 potassium iodide solution is required to completely precipitate all of the lead in 165.0 of a 0.150 lead nitrate solution?351 ml 87.8 ml 176 ml 43.9 ml
The minimum volume of 0.282 M KI solution required to completely precipitate all of the lead in 165.0 mL of 0.150 M Pb(NO3)₂ solution is 87.8 mL.
The chemical reaction that takes place when a potassium iodide solution is added to lead (II) nitrate solution is given as follows:
Pb(NO3)₂ + 2KI → 2KNO₃ + PbI₂
From the chemical reaction, it can be seen that 2 moles of KI will react with 1 mole of Pb(NO3)₂ to yield 1 mole of PbI₂. The number of moles of lead nitrate in the given volume can be calculated as follows:
n = M × V
n = 0.150 M × 165.0 mL/1000
n = 0.02475 moles
The number of moles of KI required to precipitate all the lead can be calculated as follows:
n = 0.5 × 0.02475
n = 0.012375 moles
The volume of 0.282 M KI solution required can be calculated as follows:
V = n × M-1
V = 0.012375 moles × 0.282 L/mole
V = 0.00349 L
V = 3.49 mL
V = 87.8 mL (rounded off to three significant figures)
The answer is that 87.8 ml of 0.282 M potassium iodide solution is required to completely precipitate all of the lead in 165.0 ml of a 0.150 M lead (II) nitrate solution.
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Antifreeze is used in automobile radiators to keep the coolant from freezing. In geographical areas where winter temperatures go below the freezing point of water, using pure water as the coolant could allow the water to freeze. Since water expands when it freezes, freezing coolant could crack engine blocks, radiators, and coolant lines. The main component in antifreeze is ethylene glycol, C2H4(OH)2 What is the concentration of ethylene glycol in a solution of water, in molality, if the freezing point dropped by 2.640C? The freezing point constant, kf, for water is 1.86C/m. 2) A solution of 10.0g of sodium chloride is added to 100.0g of water in an attempt to elevate the boiling point. What is the boiling point of the solution? kb for water is 0.520c/m .
Boiling point of the solution ≈ 100.9672°C
To determine the concentration of ethylene glycol in a solution of water in molality, we can use the equation:
ΔTf = kf * molality
Given that the freezing point dropped by 2.64°C and kf for water is 1.86°C/m, we can rearrange the equation to solve for molality:
molality = ΔTf / kf
Substituting the values, we get:
molality = 2.64°C / 1.86°C/m
molality ≈ 1.42 m
For the second question, to calculate the boiling point of the solution, we can use the equation:
ΔTb = kb * molality
Given that kb for water is 0.52°C/m, and the solution contains 10.0g of sodium chloride dissolved in 100.0g of water, we need to convert the masses to moles:
moles of sodium chloride = mass / molar mass
moles of sodium chloride = 10.0g / (22.99g/mol + 35.45g/mol) ≈ 0.186 mol
molality = moles of solute / mass of solvent (in kg)
molality = 0.186 mol / 0.1 kg = 1.86 m
Substituting the values into the equation, we get:
ΔTb = 0.52°C/m * 1.86 m
ΔTb ≈ 0.9672°C
The boiling point of the solution is the sum of the boiling point of pure water (100°C) and the ΔTb:
Boiling point of the solution = 100°C + 0.9672°C
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How do you figure out the number of
electrons in a neutrally charged atom?
Answer:
The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
Answer:
The number of protons in the nucleus of the atom is equal to the atomic number.
The number of electrons in a neutral atom is equal to the number of protons.
Explanation:
Which of the following organic solvents would be suitable for use in the extraction of an aqueous solution?
a. methanol
b. hexane
c. acetone
d. ethanol
e. none of the above
None of the above solvents (methanol, hexane, acetone, ethanol) would be suitable for the extraction of an aqueous solution.
In order to extract an aqueous solution, an organic solvent that is immiscible with water is typically used. Methanol, acetone, and ethanol are all miscible with water, meaning they can mix and dissolve in water. Hexane, on the other hand, is immiscible with water but it is a non-polar solvent, which makes it unsuitable for extracting polar compounds from an aqueous solution.
The suitable solvents for extracting an aqueous solution are typically non-polar solvents that do not mix with water. Examples of such solvents include diethyl ether, dichloromethane (methylene chloride), and ethyl acetate. These solvents have low polarity and can effectively separate non-polar or slightly polar compounds from an aqueous solution through liquid-liquid extraction. They form distinct layers with water, allowing for the separation of the organic phase containing the extracted compounds.
Therefore, the correct answer is e. none of the above, as none of the solvents mentioned (methanol, hexane, acetone, ethanol) are suitable for the extraction of an aqueous solution.
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A person accidentally swallows a drop of liquid oxygen, O2(l), which has a density of 1.149 g/mL. Assuming the drop has a volume of 0.053 mL, what volume of gas will be produced in the person's stomach at body temperature (37°C) and a pressure of 1.0 atm?
Answer:
First, let's determine how many moles of oxygen we have.
Atomic weight oxygen = 15.999
Molar mass O2 = 2*15.999 = 31.998 g/mol
We have 3 drops at 0.050 ml each for a total volume of 3*0.050ml = 0.150 ml
Since the density is 1.149 g/mol,
we have 1.149 g/ml * 0.150 ml = 0.17235 g of O2
Divide the number of grams by the molar mass to get the number of moles 0.17235 g / 31.998 g/mol = 0.005386274 mol
Now we can use the ideal gas law. The equation PV = nRT where P = pressure (1.0 atm) V = volume n = number of moles (0.005386274 mol) R = ideal gas constant (0.082057338 L*atm/(K*mol) ) T = Absolute temperature ( 30 + 273.15 = 303.15 K)
Now take the formula and solve for V, then substitute the known values and solve.
PV = nRT V = nRT/P V = 0.005386274 mol * 0.082057338 L*atm/(K*mol) * 303.15 K / 1.0 atm V = 0.000441983 L*atm/(K*) * 303.15 K / 1.0 atm V = 0.133987239 L*atm / 1.0 atm V = 0.133987239 L
So the volume (rounded to 3 significant figures) will be 134 ml.
The volume of the gas that will be produced in the person's stomach at body temperature (37°C) and a pressure of 1.0 atm is 48.36 mL
We'll begin by calculating the mass of the liquid oxygen. This can be obtained as follow:
Density = 1.149 g/mL
Volume = 0.053 mL
Mass =?Mass = Density × Volume
Mass of O₂ = 1.149 × 0.053
Mass of O₂ = 0.060897 gNext, we shall determine the number of mole in 0.060897 g of O₂.
Mass of O₂ = 0.060897 g
Molar mass of O₂ = 2 × 16 = 32 g/mol
Mole of O₂ =?
Mole = mass / molar mass
Mole of O₂ = 0.060897 / 32
Mole of O₂ = 0.0019 moleFinally, we shall determine the volume of the gas produced in the stomach. This can be obtained as follow:
Mole of O₂ (n) = 0.0019 mole
Temperature (T) = 37 °C = 37 + 273 = 310 K
Pressure (P) = 1 atm
Gas constant (R) = 0.0821 atm.L /Kmol
Volume (V) =? PV = nRT1 × V = 0.0019 × 0.0821 × 310
V = 0.04836 L
Multiply by 1000 to express in mL
V = 0.04836 × 1000
V = 48.36 mLTherefore, the volume of the gas produced in the person's stomach is 48.36 mL
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