Answer:
Identify a process that is NOT reversible.
Melting of snow
baking of bread
deposition of carbon dioxide
freezing water
melting of aluminum
Explanation:
A physical change is the one in which there is a change only in its physical state, color, the appearance of the substance. But the chemical composition of the substance remains unchanged.
It is a temporary change and can be reversed easily.
For example:
melting, freezing, deposition etc.
Baking is a permanent change and the chemical composition of the substance changes.
Hence, among the given options, baking of bread is not a reversible change.
Out of the following all are physical changes except baking of bread and physical changes are reversible so the process which is not reversible is baking of bread.
What are physical changes?Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.
Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.
They involve only rearrangement of atoms and are often characterized to be changes which are reversible.
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Determine the end (final) value of n in a hydrogen atom transition, if the electron starts in and the atom emits a photon of light with a wavelength of 486 nm. Group of answer choices
Complete Question
Determine the end (final) value of n in a hydrogen atom transition, if the electron starts in n=4 and the atom emits a photon of light with a wavelength of 486 nm. Group of answer choices
Answer:
[tex]n=2[/tex]
Explanation:
From the question we are told that:
Wavelength [tex]\lambda=486nm=>486*10^{-9}[/tex]
Generally the equation for Atom Transition is mathematically given by
[tex]\frac{1}{\lambda}=R_{\infty }(\frac{1}{n_1^2}-\frac{1}{n_2^2})[/tex]
Where
Rydberg constant [tex]R_{\infty}=1.097*10^7[/tex]
Therefore
[tex]\frac{1}{486*10^{-9}}=1.097*10^7*(\frac{1}{n_1^2}-\frac{1}{4^2})[/tex]
[tex](\frac{1}{n_1^2}-\frac{1}{4^2})=\frac{1}{486*10^{-9}*1.097*10^7}[/tex]
[tex]n_1^2=3.98[/tex]
[tex]n=1.99[/tex]
[tex]n=2[/tex]
Using the Rydberg formula, the final state of the electron is n=2.
Using the Rydberg formula;
1/λ = R(1/nf^2 - 1/ni^2)
Where;
λ = wavelength
nf = final state
ni = initial state
R = Rydberg constant
When λ = 486 × 10^-9 m and ni = 4, R = 1.097 × 10^7 m-1
1/486 × 10^-9 = 1.097 × 10^7(1/nf^2 - 1/4^2)
0.188 = 1/nf^2 - 0.0625
1/nf^2 = 0.188 + 0.0625
nf = 2
Missing parts;
Determine the end (final) value of n in the hydrogen atom transition, if electron starts in n-4 and the atom emits a photon of light with a wavelength of 486.
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Please help me ASAP I’ll mark Brainly
Answer:
1. Vacuole
2. chloroplast
3. Nucleus
4. Plasma membrane - cell membrane
5. Vacuole (same as #1 ?) could be vesicle
Explanation:
A Bronsted-Lowry acid is defined as a substance that ________. A Bronsted-Lowry acid is defined as a substance that ________. increases Ka when placed in H2O increases [OH-] when placed in H2O acts as a proton donor acts as a proton acceptor decreases [H ] when placed in H2O
Answer: A Bronsted-Lowry acid is defined as a substance that acts as a proton donor.
Explanation:
A substance that is able to donate a proton or hydrogen ion to another substance is a Bronsted-Lowry acid.
For example, HCl is a Bronsted-Lowry acid as it dissociates to give a hydrogen ion.
[tex]HCl \rightleftharpoons H^{+} + Cl^{-}[/tex]
Thus, we can conclude that a Bronsted-Lowry acid is defined as a substance that acts as a proton donor.
Calculate the displacement (the total volume of the cylinder through which the piston move) of a 5.70L automobile engine in cubic inches, (1inch=2.54cm)
Answer:
348 inches³
Explanation:
From our previous knowledge of units conversion:
We know that 1000 cm³ makes 1 Liter.
Thus, for a 5.70 L automobile engine in cubic meters will be:
= 5.70 × 1000 cm³
= 5700 cm³
Now, the displacement of the automobile in cubic inches provided that 1 inch = 2.534 cm is:
⇒ 5700× (1/ (2.54)³) in³
= 5700×0.0610 in³
= 347.7 in³
≅ 348 inches³
What is the amount of solute required if the solution is 50 ml and the solvent is 35 ml. Solve and explain
I don’t know what to do
Answer:
15 mL of the solute
Explanation:
From the question given above, the following data were obtained:
Solution = 50 mL
Solvent = 35 mL
Solute =?
Solution is simply defined as:
Solution = solute + solvent
With the above formula, we can easily obtain the solute in the solution as follow:
Solution = 50 mL
Solvent = 35 mL
Solute =?
Solution = solute + solvent.
50 = solute + 35
Collect like terms
50 – 35 = solute
15 = solute
Solute = 15 mL
Therefore, 15 mL of the solute is required.
What is the phase of water at 0.25 atm and 0°C?
Water
(liquid)
Pressure (atm)
0.5-
0.25
Ice
(solid)
Water vapor
(gas)
0
000
Temperature (°C)
O A. Gas
O B. Solid and gas
O C. Solid and liquid
D. Solid
Water is in the solid phase at 0.25 atm and 0°C.
In what phase is water at 25?A pressure of 50 kPa and a temperature of 50 °C correspond to the “water” region—here, water exists only as a liquid. At 25 kPa and 200 °C, water exists only in the gaseous state.
What phase is water in at 0 C?Under standard atmospheric conditions, water exists as a liquid. But if we lower the temperature below 0 degrees Celsius, or 32 degrees Fahrenheit, water changes its phase into a solid called ice.
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Is it better to use graphite or carbon electrodes during electrolysis if I am trying to investigate volume of gas produced ?
Answer:
yes
Explanation:
it is important for electrolysis
Increasing the thermal energy of a solution means you are __ it and increasing the __energy.
Answer:
heating, thermal
Explanation:
the more molecules present, the greater amount from any given source increases the temperature as well as the thermal energy.
Draw the structure of the alkene with the molecular formula C6H10 that reacts with Br2 to give this compound.
Answer: Please, this question is not complete. I have attached the complete question.
The answer is in the attached picture below
Explanation:
The explanation is in the attached picture below
The structure of the alkene with the molecular formula [tex]C_6H_1_0[/tex] that reacts with [tex]Br_2[/tex]to give this compound is an alkene called 1-hexene
How do we explain?The alkene is called 1-hexene. It has a double bond between the first and second carbon atoms. When it reacts with Br2, the bromine atoms add to the double bond, resulting in the formation of 1,2-dibromohexane.
The reaction is a radical addition reaction. The first step is the formation of a radical by the homolytic cleavage of one of the bromine atoms in Br2. This radical then adds to the double bond in the alkene, forming a new radical. The second bromine atom then adds to the radical, forming 1,2-dibromohexane
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A vessel is filled at a rate of 3.41 cubic micrometers per minute. If the vessel has a volume of 54 liters, how many
seconds will it take to fill the vessel? provide a step buy step explanation.
Answer:
9.5x10¹⁷ s
Explanation:
First we convert 3.41 cubic micrometers (um³) to liters (L), as such:
3.41 um³ * [tex](\frac{1m}{10^6um} )^3*\frac{1000L}{1m^3}[/tex] = 3.41x10⁻¹⁵ LWith the converted rate of 3.41x10⁻¹⁵ L/min, we can calculate how many minutes it would take to fill a 54 L vessel:
54 L ÷ 3.41x10⁻¹⁵ L/min = 1.58x10¹⁶ minFinally we convert 1.58x10¹⁶ minutes to seconds:
1.58x10¹⁶ * 60 = 9.5x10¹⁷ sAccording to the Arrhenius equation, changing which factors will affect the
rate constant?
A. Temperature and the ideal gas constant
B. The activation energy and the constant A
C. The constant A and the temperature
D. Temperature and activation energy
Answer:
e−(Ea/RT): the fraction of the molecules present in a gas which have energies equal to or in excess of activation energy at a particular temperature
Answer:
D. Temperature and activation energy is the correct answer
Explanation:
^_^
What type of a liquid will have a pH value equal to 12? (1 point)
Basic
Neutral
Strong acid
Weak aci
Answer: it will be basic
pH that ranges from 0-6 are acid
pH of EXACTLY 7 is neutral
pH greater than 7 are strongly basic or base
According to Newton's law of universal gravitation, how do the masses of two
objects relate to the gravitational force between them?
A. As either mass increases, the gravitational force between them
increases.
B. As either mass increases, the gravitational force between them
decreases.
C. Gravitational force increases only when both masses increase.
D. Gravitational force increases only when both masses decrease.
Answer:
As either mass increases, the gravitational force between them
increases.
Explanation:
According to Newton's law of universal gravitation;
F α m1m2/r^2
That is, the force between two masses in a gravitational field is directly proportional to the product of the two masses and inversely proportional to their distance apart.
Hence, as either of the masses increase, the force of gravitation between the two masses increases. Hence the answer.
Draw the Lewis structure for the polyatomic formate anion. Be sure to include all resonance structures that satisfy the octet rule.
Answer:
Lewis structure of polyatomic formate anion.
Explanation:
To draw Lewis structure for any chemical species,
1)Count the total number of valence electrons present in it.
This can be obtained by adding valence electrons of each constituent atom.
2)Arrange those valence electrons in such a way that each atom should attain eight electrons around it to satisfy octet theory.
The structure of formate ion and its Lewis structure are shown below:
HCOO- is the formate ion.
It has total:
1+4+6+6+1 = 18 valence electrons.
Since, hydrogen has one, carbon has four and oxygen has six valence electrons and the charge of the anion is one.
Arrange this 18 electrons in such a way that each atom should get 8 electrons around it.
Resonance structures of formate ion:
Determine the theoretical yield and the percent yield if 21.8 g of K2CO3 is produced from reacting 27.9 g KO2 with 57.0 g CO2. The molar mass of KO2
Answer:
26.9 g
81%
Explanation:
The equation of the reaction is;
4 KO2(s) + 2 CO2(g) → 3 O2(g) + 2 K2CO3(s)
Number of moles of KO2= 27.9g/71.1 g/mol = 0.39 moles
4 moles of KO2 yields 2 moles of K2CO3
0.39 moles of KO2 yields 0.39 × 2/4 = 0.195 moles of K2CO3
Number of moles of CO2 = 57g/ 44.01 g/mol = 1.295 moles
2 moles of CO2 yields 2 moles of K2CO3
1.295 moles of CO2 yields 1.295 × 2/2 = 1.295 moles of K2CO3
Hence the limiting reactant is KO2
Theoretical yield = 0.195 moles of K2CO3 × 138.205 g/mol = 26.9 g
Percent yield = actual yield/theoretical yield × 100
Percent yield = 21.8/26.9 × 100
Percent yield = 81%
calculate the molarity in a 0.550 m solution of NaCl in water. Assume that the solution density is 1.03g/mol
Answer:
M=0.549M
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to perform this calculation by firstly assuming we have 1 kg of water as the solvent so that we have 0.550 moles of NaCl as well. Moreover, we realize we have 1000 grams of water and the correct mass of the solution can be calculated by converting 0.550 moles of NaCl to grams by using its molar mass:
[tex]m_{solute}=0.550mol*\frac{58.44 g}{1mol}= 32.14g\\\\m_{solution}=1000g+32.14g=1032.14g[/tex]
And subsequently, the volume in liters by using the density and the correct conversion factor:
[tex]V_{solution}=1032.14g*\frac{1mL}{1.03g} *\frac{1L}{1000mL} =1.002L[/tex]
Finally, the molarity will be:
[tex]M=\frac{0.550mol}{1.002L} =0.549M[/tex]
Regards!
Og is the noble gas after Rn. To go from [Rn] to [Og], you must fill four subshells (s, p, d, and f) with a total of 32 electrons. Thus, the atomic numbers of 6th and 7th period elements of the same group differ by 32.
a. To go from [Og] to the next noble gas, however, you would theoretically fill five subshells (s, p, d, f, and g). How many electrons are needed to fill all five subshells?
b. Element 106 in the periodic table is Sg Determine the atomic number of the element just below Sg in the periodic table.
Answer:
See explanation
Explanation:
Since we have to fill five subshells in moving from Og to the next noble gas in the eight period, we have to know the maximum electrons contained in each of those subshells;
s= 2, p=6, d= 10, f= 14, g = 18
This means that we need a total of 50 electrons to fill all the five subshells.
Hence, the element just below Sg in the eight period will have an atomic number of 156.
20.1 cm3 of metal hydroxide (MOH) containing 4.8 g/dm3 react Completely with 23.0 cm3 of the HCL and Containing 3.8g/dm3. Identify the metal of M of MOH
Answer:
A metal M readily forms water-soluble sulphate MSO4, water-insoluble hydroxide M(OH)2 and oxide MO. The oxide and hydroxide are soluble in NaOH. The M is:
EXTRACTION OF CAFFEINE 1.Explain the reason each step of the separation is performed with three portions of the solvent rather than with a single portion of solvent. (e.g. Done in triplicate.) (0.5 pt) 2.Why should a separatory funnel not be vigorously shaken
Answer:
Throughout the explanations section below you will find a description of the question.
Explanation:
(1)
Whether a solution would be positioned inside a separative funnel, combined water, as well as solvent, disintegrate particulate caffeine. In every stage, the caffeine content incorporated relies upon the coefficient of caffeine partitioning throughout the combination of water as well as fluid.Thus, increasingly caffeine is taken from the solvent whenever the moment you bring additional solvent. Consequently, we separate the solvent from the single component.(2)
For compounds to be mixed thoroughly and separated into different layers, a shuddering mixture within the dividing funnel would be essential.However, it vibrates the separation funnel forcefully, restricts airflow within the funnel, which can also induce the fluid under it to burst or causing fluid to fire.Suppose you analyze a 30.3 g sample of bleach and determine that there are 2.61 g of sodium hypochlorite present. What is the percent of sodium hypochlorite in the bleach sample
Answer:
8.61 %
Explanation:
The percent of sodium hypochlorite in the bleach sample can be calculated using the following formula:
% of sodium hypochlorite = Mass of sodium hypochlorite / mass of sample * 100%We input the data given by the problem:
% of sodium hypochlorite = 2.61 g / 30.3 g * 100 % = 8.61 %The addition of chromic acid or chromate is a qualitative test for alcohols as the reaction causes a color change. However, not all alcohols react with chromic acid or chromate. Determine whether the named alcohol will react with chromic acid or chromate to cause a color change.
a. 3-hexanol
b. 1 -butanol
c. 2-pentanol
d. 3-ethyl-3-pentanol
Answer:
3-hexanol
1 -butanol
2-pentanol
Explanation:
Let us recall that chromic acid or chromate are strong oxidizing agents. When they are oxidized, their colour changes from orange to green.
This shows a reduction in chromic acid or chromate. The reaction of chromic acid or chromate with a primary alcohol yields a carboxylic acid while reaction with a secondary substrate yields an alkanal.
Note that Tertiary alkyl halides are not be oxidized hence reactions involving a point where invitation carried along occur.
3-ethyl-3-pentanol is a tertiary alkyl halide hence it can not be oxidized.
How many stereoisomers are possible for CHCl3 provided that the central carbon has a tetrahedral geometry
Answer:
How many stereoisomers are possible for CHCl3 provided that the central carbon has tetrahedral geometry?
Explanation:
The stereoisomers are the molecules with the same molecular formula but the different spatial arrangements of atoms around the central atom.
For the given molecule, [tex]CHCl_3[/tex]
only one spatial arrangement is possible.
Hence, one stereoisomer is possible.
It is shown below:
. The nucleophile in the reaction is _______ b. The Lewis acid catalyst in the reaction is ______ c. This reaction proceeds___________(faster or slower) than benzene. d. Draw the structure of product D
Answer:
a. eletrophile
b. able to impose regioselectivity and stereo selectivity.
c. faster
Explanation:
Necleophile reaction is chemical reaction in which electron rich chemical specie replaces functional group with another electron deficient molecule. Lewis acid catalyst is organic chemical reaction which lewis acid act as electron pair acceptor. Nucleophile reaction proceeds about 25 times more faster than benzene.
What were the advantages for Mendel in using pea plants for his breeding experiments?
Answer:
He chose pea plants because they were easy to grow, could be bred rapidly, and had several observable characteristics, like petal color and pea color.
Explanation:
Suppose of potassium acetate is dissolved in of a aqueous solution of ammonium sulfate. Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it. Round your answer to significant digits.
The question is incomplete, the complete question is;
Suppose 0.377g of potassium acetate is dissolved in 250.mL of a 57.0mM aqueous solution of ammonium sulfate.
Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.
Round your answer to 3 significant digits.
Answer:
0.0152 M
Explanation:
The equation of the reaction is;
2CH3COOK(aq) + (NH4)2SO4(aq)------> K2SO4(aq) + 2CH3COONH4(aq)
Number of moles of potassium acetate = 0.377g/98.15 g/mol = 0.0038 moles
Number of moles of ammonium sulphate = 250/1000L × 57 × 10^-3 = 0.014 moles
2 moles of potassium acetate yields 2 moles of ammonium acetate
Hence;
0.0038 moles of potassium acetate yields 0.0038 moles of ammonium acetate
Also
1 mole of potassium sulphate yields 2 moles of ammonium acetate
0.014 of potassium sulphate yields 0.014 × 2/1 = 0.028 moles of ammonium acetate
So potassium acetate is the limiting reactant.
Since 0.0038 moles of ammonium acetate is produced, the final concentration of potassium acetate is = 0.0038 moles of ammonium acetate/0.25L = 0.0152 M
Hence final concentration of acetate ions =0.0152 M
A balloon contains 0.118 mol of gas and has a volume of 2.58 L . If an additional 0.116 mol of gas is added to the balloon (at the same temperature and pressure), what will its final volume be? Can you also show the work so I can understand why is it that answer. thank you
Answer:
v2=5.11L
Explanation:
given
v1=2.58L
N1=0.118mol
N2=0.234
v2=x
according to charles law V1/N1=V2/N2
2.58/0.118=V2/0.234
21.86=V2/0.234
21.86×0.234= v2
5.116L=v2
5.116L is the
answer or u can simplify it and make 5.1 L
Explain the sample prep for IR
Answer:
) Making a sandwich To prepare a liquid sample to IR analysis, firstly place a drop of the liquid on the face of a highly polished salt plate (such as NaCl, AgCl or KBr), then place a second plate on top of the first plate so as to spread the liquid in a thin layer between the plates, and clamps the plates together.
How many moles of carbon dioxide at STP will fit in a 50 liter container?
Answer:
n = 2.23 moles
Explanation:
Given the following data;
Standard temperature = 273 K
Standard pressure = 101.325 kPa
Volume = 50 liter
R = 8.314 J/mol·K
To find the number of moles, we would use the ideal gas law formula;
PV = nRT
Where;
P is the pressure.V is the volume.n is the number of moles of substance.R is the ideal gas constant.T is the temperature.Making n the subject of formula, we have;
[tex] n = \frac {PV}{RT} [/tex]
Substituting into the formula, we have;
[tex] n = \frac {101.325*50}{8.314*273} [/tex]
[tex] n = \frac {5066.25}{2269.722} [/tex]
n = 2.23 moles
Therefore, 2.23 moles of carbon dioxide at STP will fit in a 50 liter container.
In what kind of orbital do the lone-pair electrons on the nitrogen of dimethylacetamide reside, and is it in the same plane as the ch3 groups
Answer:
The lone pairs on nitrogen in dimethylacetamide reside in sp3 orbitals which are coplanar with the methyl groups
Explanation:
The compound dimethylacetamide consists of oxygen bearing two lone pairs of electrons and a nitrogen atom bearing a lone pair of electrons and has two methyl groups attached to the nitrogen atom.
The lone pair on the nitrogen atom is accommodated in an sp3 orbital of nitrogen as shown in the question. This sp3 orbital is coplanar with the two methyl groups.
Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Answer:
Classify each of the following as either macroscopic, microscopic or particulate:
a. a red blood cell.
b. a sugar molecule.
c. baking powder.
Explanation:
a. A red blood cell is a microscopic particle.
It can be viewed under a microscope.
b. A sugar molecule is also a microscopic substance.
It can be viewed under a microscope.
c. Baking powder is macroscopic substance.
