Answer:
Most substances on earth are compounds and most interesting chemistry is done with compounds. Most interesting chemistry is done with mixtures of compounds although they often start with pure compounds and then do reactions as mixtures. Most chemistry is carried out in liquid solutions made up of compounds that are solids, liquids, or gases in their pure form.
Explanation:
Here, we are required to determine which of these methods of classifying substances is most important to chemists.
The most useful classification of compounds to chemists is as Elements, Compounds or MixturesFirst classification of substances involves categorising them as pure substances (elements and compounds) or mixtures.
The second classification of substances is categorisation with respect to their state of matter. In essence, we can have solid, liquid or gas.
However, the most useful classification of compounds to chemists is as Elements, Compounds or Mixtures.This is so because, the type of matter present in Elements are distinct for each element, same as for Compounds and Mixtures formed from a combination of pure substances.
Chemists focus on the diverse properties of substances, as such classification as elements, compounds and mixtures provides a wide basis for the qualitative and quantitative analysis of the properties of substances.Classification of substances as solid, liquid or gas leaves a narrow avenue for the study of substances as the substance still contains the same type of matter, only this time in different states.Read more:
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What is the de broglie wavelength of an electron (m = 9. 11 × 10-31 kg) moving at a velocity of 3. 0 × 107 m/s?
the de Broglie wavelength of the electron moving at a velocity of 3. 0 × 107 m/s is 2.4×10∧-11nm
lambda = h/mv
The de Broglie wavelength is defined as follows: lambda = h/mv, wherein the greek letter lambda represents the wavelength, h is Planck's consistent, m is the particle's mass and v is its pace. One may also explicit mv as the particle's momentum
according to wave-particle duality, the De Broglie wavelength is a wavelength manifested in all the gadgets in quantum mechanics which determines the chance density of locating the item at a given factor of the configuration area. The de Broglie wavelength of a particle is inversely proportional to its momentum
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If the dissociation constant of a weak acid is 7.1 x 10-5, at what ratio should you adjust the concentration of the weak acid and its conjugate base in order to prepare a buffer that has a pH of 4.15
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A certain amount of substance has a mass of 120 g and the number of moles is 2. Calculate the molar mass. Group of answer choices
Answer:
60 g / mole
Explanation:
120 g / 2 mole = 60 g/mole
______ is a naturally occurring metal found in the environment as well as manufactured in products. The major source of this metal has historically been from fuels in on-road motor vehicles such as cars and trucks, and industrial sources.
Lead is a naturally occurring metal found in the environment as well as manufactured in products. The major source of this metal has historically been fuels in on-road motor vehicles such as cars and trucks, and industrial sources.
Lead: An Air PollutantBoth naturally occurring in the environment and used in manufactured goods are the metal lead. In the past, industrial sources and fuels used in on-road motor vehicles (such as cars and trucks) have been the main sources of lead emissions. Lead emissions from the transportation industry rapidly reduced by 95% between 1980 and 1999 thanks to regulatory measures in the U.S. to remove lead from gasoline for on-road motor vehicles, while lead levels in the air decreased by 94% over the same period. The areas closest to lead smelters typically have the greatest airborne lead concentrations today. Today, the processing of ores and metals as well as piston-engine aircraft using leaded aviation gasoline are the main sources of lead emissions into the atmosphere.
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Help me pls!!!!!!!!!!!!!!!!!!!!!
The liberated electron will have 10.28 eV kinetic energy.
Given that light of frequency 3.62 × [tex]10^{15}[/tex] Hz strikes a surface of copper metal with work function([tex]W_{0}[/tex] = 4.70 eV).
The incident (photon) energy given as hf (Planck's Constant time's frequency) minus the energy that "binds" the electron to the metal (the work function) will equal the maximum kinetic energy of the emitted electron.
K.E. = hf − ϕ
Where K = Kinetic energy
h = Planck's constant = 6.62607015 × [tex]10^{-34}[/tex] J s
f = frequency = 3.62 × [tex]10^{15}[/tex] Hz
ϕ = 4.70 eV = 4.7 × 1.6 × [tex]10^{-19}[/tex] = 7.52 × [tex]10^{-19}[/tex]
K.E. = 6.62607015 × [tex]10^{-34}[/tex] × 3.62 × [tex]10^{15}[/tex] - 7.52 × [tex]10^{-19}[/tex]
= 6.62607015 × 3.62 × [tex]10^{-19}[/tex] - 7.52 × [tex]10^{-19}[/tex]
= 23.98 × [tex]10^{-19}[/tex] - 7.52 × [tex]10^{-19}[/tex]
K.E. = 16.46 × [tex]10^{-19}[/tex] J = 10.28 eV
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A sample of propane (C3H8) has a mass of 0.47 g. The sample is burned in a bomb calorimeter that has a mass of 1.350 kg and a specific heat of 5.82 J/(g • °C). How much energy is released by the reaction if the temperature of the calorimeter rises by 2.87°C?
Use q equals m C subscript p Delta T..
7.85 kJ
10.6 kJ
22.5 kJ
47.9 kJ
Propane is burned in a 1.350-kg bomb calorimeter with a specific heat of 5.82 J/g.°C. For a temperature rise of 2.87 °C, the energy released is 22.5 kJ.
What is a bomb calorimeter?It is a device that can measure heats of combustion, used in various applications such as calculating the calorific value of foods and fuels.
A sample of propane is burned in a bomb calorimeter with a mass (m) of 1.350 kg and a specific heat (c) of 5.82 J/g.°C. All the energy released by the propane is absorbed by the bomb calorimeter.
If the temperature rises by 2.87 °C (ΔT), we can calculate the energy released (Q) using the following expression.
Q = c × m × ΔT = 5.82 J/g.°C × 1,350 g × 2.87 °C × (1 kJ/1000 J)
Q = 22.5 kJ
Propane is burned in a 1.350-kg bomb calorimeter with a specific heat of 5.82 J/g.°C. For a temperature rise of 2.87 °C, the energy released is 22.5 kJ.
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Answer:
22.5 kj
Explanation:
The elements of the group IA are termed as alkali metals, because their ___ are alkaline.
The answer is hydroxides.
The elements of the group IA are termed as alkali metals, because their hydroxides are alkaline.
Experiment 1: in the synthesis reaction, the white powder produced is magnesium oxide (mgo, mm = 40.3 g/mol). how many moles (n) of magnesium oxide were formed? select the closest answer.
1.98 moles of Magnesium oxide were formed.
What is Balanced Chemical Equation ?The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
Now write the balanced chemical equation
2Mg + O₂ → 2MgO
(2 × 24) 2 × (24 + 16)
48 g of Mg gives 80 g of MgO
How to find the number of moles ?To find the number of moles use the expression
Number of moles = [tex]\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
= [tex]\frac{80}{40.3}[/tex]
= 1.98 mole
Thus from the above conclusion we can say that 1.98 moles of Magnesium oxide were formed.
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Which is more precise
164 or 165 if the true value is 167
Gaseous nitrogen dioxide dissolved in warm liquid water to form hno3 and gaseous nitrogen monoxide enter a balanced equation for this reaction
Answer:
3 NO₂ (g) + H₂O (l) ---> 2 HNO₃ (aq) + NO (g)
Explanation:
Gaseous nitrogen dioxide = NO₂ (g)
Liquid water = H₂O (l)
Because the reactants are dissolved = HNO₃ (aq)
Gaseous nitrogen monoxide = NO (g)
In order for a reaction to be balanced, there needs to be an equal amount of each type of atom on both sides of the equation. The equation can be balanced by adding coefficients to modify the quantities of certain compounds.
The unbalanced equation:
NO₂ (g) + H₂O (l) ---> HNO₃ (aq) + NO (g)
Reactants: 1 nitrogen, 3 oxygen, 2 hydrogen
Products: 2 nitrogen, 4 oxygen, 1 hydrogen
The balanced equation:
3 NO₂ (g) + H₂O (l) ---> 2 HNO₃ (aq) + NO (g)
Reactants: 3 nitrogen, 7 oxygen, 2 hydrogen
Products: 3 nitrogen, 7 oxygen, 2 hydrogen
5.690x10^3 miles to meters and give sig figs
Please help!
The equivalent of 5.690 × 10³ miles in metres is 9157167 metres. Details about metres and miles can be found below.
How to convert miles to metres?Miles and metres are both units for measuring distance between two bodies or locations.
However, they can be converted interchangeably as follows:
1 mile = 1609.34 metres
According to this question, 5.690 × 10³ miles can be converted to metres as follows;
5.690 × 10³ × 1609.34 = 9157167 metres.
Therefore, the equivalent of 5.690 × 10³ miles in metres is 9157167 metres.
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The molar mass of calcium chloride (CaCl₂) is
110.98 g/mol. If you were to calculate the number
of moles in 23.4 g of CaCl₂, which example shows
the correct way to set up the calculation?
O
23.4 g CaCl₂x.
O
110.98 g CaCl₂
1mole CaCl₂
1 mole CaCl₂
110.98 g CaCl₂
23.4 g CaCl₂x-
The example that shows the correct way to set up the calculation will be the second example.
Number of molesMathematically:
Number of moles = mass/molar mass
In this case, mass = 23.4 g and molar mass = 110.98 g/mol
Number of moles = 23.4/110.98 = 0.21 moles
Thus, the second example is the correct way.
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The half-life of silicon-32 is 710 years. If 40 grams is present now, how much will be present in 800 years
18 g of silicon-32 will be present in 800 years.
A radioactive half-life refers to the amount of time it takes for half of the original isotope to decay and it's given by
[tex]N(t) = N_0 (\frac{1}{2}) ^\frac{t}{t_\frac{1}{2} }[/tex]
where,
[tex]N(t) =[/tex] quantity of the substance remaining
[tex]N_0 =[/tex] the initial quantity of the substance
[tex]t =[/tex] time elapsed
[tex]t_1_/_2 =[/tex] the half-life of the substance
From the given information we know:
The initial quantity of silicon-32 is 40 g.
The time elapsed is 800 years.
The half-life of silicone-32 is 710 years.
So, using the calculation above, we can determine how much silicon-32 is left.
[tex]N(t) = 40 (\frac{1}{2}) ^\frac{800}{710} \\N(t) = 40 (\frac{1}{2}) ^\frac{80}{71} \\\\N(t) = 18 g[/tex]
Therefore,18 g of silicon-32 will be present in 800 years.
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A chemist develops a medicine
to help patients with thyriod
problems. In which branch of
chemistry is this chemist
working.
Answer:
Medicinal Chemistry
Explanation:
Medicinal Chemistry deals with the development, design and production of medicines.
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A balloon contains a 10% glucose solution. The balloon is permeable to water but not to glucose. A beaker contains a 5% glucose solution. What will happen when the balloon is submerged in the beaker
The state of the balloon:
When the balloon is submerged in the beaker, the amount of water in the beaker will get reduced.
What is Osmosis:
Based on the concentration of solutes on both sides of the membrane, water will flow through a permeable membrane in a specific direction.
Hypertonic solution:
It means that there are more solutes present in the surrounding environment than in the cell itself.
Hypotonic solution:
In a hypotonic solution, the concentration of solutes inside the cell is higher than that outside the cell.
When comparing two solutions, the one with the larger solute concentration is hypertonic, and the one with the lower solute concentration is hypotonic. Isotonic solutions have an identical solute concentration.While the solution in the beaker is hypertonic, Meaning that will draw water molecules out of the cell. As water molecules move from a location of high water potential (dilute solution) to a region of reduced water potential (10% glucose solution), the water from the 5% glucose solution will flow into the 10% one (concentrated solution)This is the reason why the amount of water decreases when the balloon is submerged in the beaker.Learn more about the glucose solution and permeability here,
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How many moles of carbon are in 7.87x10^7 carbon atoms
?x10^?
Answer:
1.3 x10^-16
Explanation: answered it in your comments! :)
What is δs° for the reaction so2(s) no2(g) → so3(g) no(g)? substance s°(j/k • mol) so2(g) 248.5 so3(g) 256.2 no(g) 210.6 no2(g) 240.5
The value of ΔS° for reaction is - 22.2 J/K.mol
[tex]SO_{2}(s)+NO_{2} (g)[/tex] → [tex]SO_{3}(g)+NO(g)[/tex]
Calculation,
Given value of S°(J/K.mol) for
[tex]SO_{2}(s)[/tex] = 248.5
[tex]NO_{2} (g)[/tex] = 240.5
[tex]NO(g)[/tex] = 210.6
[tex]SO_{3}(g)[/tex] = 256.2
Formula used:
ΔS° (Reaction) = ∑S°(Product) - ∑S°(Reactant)
ΔS° = (256.2 + 210.6 ) - ( 248.5 + 240.5) = 466.8 - 489 = - 22.2 J/K.mol
The change in stander entropy of reaction is - 22.2 J/K.mol. The negative sign indicates the that entropy of reaction is decreases when reactant converted into product.
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6. which metal will not be able to be oxidized by any of the other metals listed?
Metal that won't be oxidized:
Metal that will not be able to oxidize by any of the other metals is gold.
What causes oxidation to happen?
This chemical reaction might take place in the air or after the metal has been in contact with acids or water. The most prevalent example is corrosion of steel, which occurs when the iron molecules on the surface of steel change into iron oxides, most frequently Fe2O3 and Fe3O4.
If you've ever seen a rusted-out vehicle or corroded metal bits, you've witnessed oxidation in action.
Metals that don't oxidize:
In their native condition, noble metals like platinum or gold resist oxidation. Ruthenium, rhodium, palladium, silver, osmium, and iridium are more examples of these metals. Humans have developed a wide variety of corrosion-resistant alloys, including brass and stainless steel.
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In general, which solvent should be used to wash the solid material collected from a filtration?
The same solvent as the liquid in the original mixture should be used to wash the solid material collected from a filtration.
The solid material which is collected from the filtration is washed by that solvent in which that solid material is dissolved. Generally methanol solvent is used to wash the solid material collected from a filtration.
The filtration is the process in which solid particles present in liquid or gaseous fluid are removed by using of a filter.This filter is only permits or allow only the fluid to pass though it and retain the solid particles.The solid particles left is known as filtrate.learn about filtration
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When 3-methyl-2-butanone undergoes a baeyer-villiger oxidation reaction, the product is:_____.
When 3-methyl-2-butanone undergoes a baeyer-villiger oxidation reaction, the product is isopropyl acetate and methyl isobutyrate.
The Baeyer-villiger oxidation would seem to be a chemical reaction that uses peroxy acids using peroxides as the oxidant to transform a ketone into an ester or a lactone from such a cyclic ketone.
The main product produced by the Baeyer-Villiger oxidation of camphor using m-CPBA in buffer conditions could be created as a result of the migration of a tertiary bridgehead carbon as opposed to a methylene group.
By the reaction between 3-methyl-2-butanone with m-CPBA , will form isopropyl acetate and methyl isobutyrate.
It reaction can be shown as:
Therefore, when 3-methyl-2-butanone undergoes a Baeyer-villiger oxidation reaction, the product is isopropyl acetate and methyl isobutyrate.
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It is a long tube-like canal ,also called alimentary canal where digestion take place.
Explanation:
The alimentary canal is the long tube of organs - including stomaches and intestines
Answer: digestive strat.
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Based on their composition and structure list, CH2Cl2, CH3CH2CH3, and CH3CH2OH in order of: a. Increasing intermolecular forces b. Increasing viscosity c. Increasing surface tension
Based on their composition and structure list CH₂Cl₂, CH₃CH₂CH₃ and CH₃CH₂OH in order of (a) Increasing order of Intermolecular Forces are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (b) Increasing order of Viscosity are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (c) Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.
What is Intermolecular Forces ?Intermolecular forces often abbreviated to IMF (or Secondary force) are the forces that hold atoms together with in a molecule. These forces are electrostatic in nature and exist between molecules.
Increasing order of Intermolecular Forces are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.
How Intermolecular forces affect Viscosity ?Higher the intermolecular force then higher the viscosity. Stronger the intermolecular force then stronger the viscosity.
Increasing order of Viscosity are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.
How Intermolecular forces affect Surface tension ?Stronger the intermolecular forces of liquid have higher surface tension. Surface tension depend upon the intermolecular forces.
Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.
Thus from the above conclusion we can say that Based on their composition and structure list CH₂Cl₂, CH₃CH₂CH₃ and CH₃CH₂OH in order of (a) Increasing order of Intermolecular Forces are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (b) Increasing order of Viscosity are CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH. (c) Increasing order of Surface Tension are: CH₃CH₂CH₃ < CH₂Cl₂ < CH₃CH₂OH.
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Blank + 3Fe, reaction arrow, Fe3O4+4H2
How to complete this equation so that it is a Single displacement reaction
The complete reaction equation is [tex]3Fe + 4H_2O -- > Fe_3O_4 + 4H_2[/tex]
What are single displacement reactions?They are reactions in which one of the elements in a reactant is displaced by another element in the product.
In the reaction leading to the production of [tex]Fe_3O_4[/tex], Fe displaced H atoms from [tex]H_2O[/tex].
Thus, the equation of the reaction is as follows:
[tex]3Fe + 4H_2O -- > Fe_3O_4 + 4H_2[/tex]
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Cesium-137 has a half life of 30.0 years. If initially there are 8.0 kg of cesium-137 present in a sample, how many kg will remain after 60.0 years
Mass after 60 years:
2 kg of cesium-137 will remain after 60.0 years.
What is Half-life?
The duration needed for a quantity to decrease to half of its initial value is known as the half-life.
Given:
N0 = is the initial amount of cesium-137 = 8.0 Kg
N = is the amount remaining after a time = Unknown
t = Duration of cesium-137 decay in 8.0 Kg = 60 years
t1/2 = half-life of cesium-137 = 30.0 years
Formula = N/No = (1/2)^t/t1/2
After putting the value:
N/8= (1/2)^60/30
N/8= (1/2)^2
N/8= 1/4
4N= 8
N= 8/4
N= 2 Kg
As a result, 2 Kg of cesium-137 will be present after 60 years.
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How many atoms are in 76.15 grams of fe
urgently needed, will mark brainliest
Answer:
See below
Explanation:
From periodic table
mole weight of Fe is 55.845 gm / mole
76.15 gm / 55.845 gm/mol * 6.022 x 10^23 atoms/mole =
8.212 x 10^23 atoms ( four signif. digits)
The combustion of hydrogen gas releases 286 kJ per mol of hydrogen. If 13.0 L of hydrogen at STP was burned to produce electricity, how long would it power a 100-watt (W) light bulb
Combustion of hydrogen produces electricity:
It would power a 100-watt (W) light bulb in 27.66 min.
Calculation:
At STP conditions, we know that 1 mole of any gas is contained in 22.4L.
So let's make the operation:
The volume of one mole of gas at STP is 22.4 L
Then, 13.0 L may be the volume for (13.0) /22.4 = 0.58 moles.
The total energy is released = 0.58 x 286 kJ
Total energy = 165.98 kJ
Energy = Power x time
Time = energy / power
where power = 100W = 100 J/s
Therefore, Time = 165.98 kJ/ 100J/s = 1659.8 sec
Time = 1659.8 sec / 60 min = 27.66 min
∴ Time = 27.66 min
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The formula c₂H₄o can represent?
Answer:
Ethylene oxide
Explanation:
Ethylene oxide is an organic compound with the formula C2H4O. It is a cyclic either and the simplest epoxied: a three-membraned ring consisting of one oxygen atom and two carbon atoms!
Potassium secretion is linked to:________.
a. sodium reabsorption
b. glucose reabsorption
c. sodium secretion
d. chloride reabsorption
e. chloride secretion
Which is a type of star system?
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The soft ionization technique that uses a UV-absorbing compound upon which the analyte of interest is placed and eventually vaporized into a plume of ions directed into the mass analyzer is
The soft ionization technique that uses a UV-absorbing compound upon which the analyte of interest is placed and eventually vaporized into a plume of ions directed into the mass analyzer is matrix-assisted laser desorption ionization.
What is Soft ionization technique ?
Soft Ionizer produces less fragment ions. Soft ionizer produce the molecular ions or a quasi molecular ion. This technique not fragment the macromolecules into the more smaller charged particles.
Thus from the above conclusion we can say that The soft ionization technique that uses a UV-absorbing compound upon which the analyte of interest is placed and eventually vaporized into a plume of ions directed into the mass analyzer is matrix-assisted laser desorption ionization.
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