Answer:
Physical changes are those in which the shape, size, or state of the matter changes, but the substance is still essentially the same. Chemical changes are those where one or more substances are combined to produce a new substance.
Explanation:
For example, chopping up a carrot or ice melting into water are both physical changes. Chemical changes are those where one or more substances are combined to produce a new substance. At the end of a chemical change, you have a new substance. Burning a piece of paper would be a chemical change, as would baking a cake. Ozone is an invisible gas made of 3 oxygen atoms.
consider the ground state electron configurations of the following atoms and ions: a. n b. s c. ni d. cl- e. ti3 c. which atom or ion has the most valence electrons? e. which atom or ion has the fewest valence electrons? a. which atom or ion has the most unpaired electrons? d. which atom or ion has the fewest unpaired electrons?
The most valence electron is present in Cl. The fewest valence electrons are present in Ni and Ti. The most unpaired electrons are present in N. The fewest unpaired electrons are present in Cl.
What are valence electrons?
Valence electrons are the electrons present in the outermost shell of an atom that participate in formation of a chemical bond. For example, oxygen atom has total of six valence electrons. out of those 2 electrons are in the 2s subshell and 4 electrons are present in the 2p subshell. So the electronic configuration of oxygen atom can be written as 1s2 2s2 2p4.
Cl has 7 valence electrons in it. Ni and Ti have 2 valence electrons in them which is the least among the following. There are 3 unpaired electrons present in N atom which is the highest among the following atoms and Cl has 1 unpaired electron which is the lowest among the following atoms.
Therefore, the most valence electron is present in Cl. The fewest valence electrons are present in Ni and Ti. The most unpaired electrons are present in N. The fewest unpaired electrons are present in Cl among the following atoms.
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based on a kckck c value of 0.200 and the given data table, what are the equilibrium concentrations of xyxy , xx , and yy , respectively?
The Equilibrium concentrations :
[XY] = 0.268 M
[X] = 0.232 M
[Y] = 0.232 M
Solution:
XY ⇔ X + Y
0.2 + x 0.3-x 0.3 - x
Kc = [X][Y]/[XY]
0.200 = (0.3-x)^2 / 0.2 + x
0.04 + 0.2 x = 0.09 + x^2 - 0.6 x
x^2 - 0.8 x + 0.05 = 0
x = 0.732 or x = 0.0683
Equilibrium concentrations :
[XY] = 0.268 M
[X] = 0.232 M
[Y] = 0.232 M
When both the reactants and products are at concentrations that do not change over time, they are said to be in chemical equilibrium. In this state, the forward reaction rate is equal to the reverse reaction rate. A chemical is said to have equilibrium concentrations when the products and reactants do not change with time.
In other words, chemical equilibrium or equilibrium concentration is the state in which the rate of the forward reaction in a chemical reaction equals the rate of the reverse reaction. Equilibrium is when the rate of the forward reaction equals the rate of the reverse reaction. All extract and product concentrations are constant at equilibrium.
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the salad is physical or chemichal change
Answer:
physical change
Explanation:
bcoz we make salad with raw vegetables and fruits
The salad is a physical change.
Making a fruit salad with raw fruits is a physical change because in this process chemical composition of fruits is not changed.
Telling the difference between a chemical change and a physical change seems trickier than it is. The main difference between a chemical change and a physical change is what happens to a substance’s composition. Here are the basic definitions of chemical and physical changes:
chemical change – a process in which chemical bonds are broken or created to make a new substance
physical change – a process in which a substance changes its state of matter, but chemical bonds stay intact
When matter undergoes a chemical change, it can’t return to its original state without additional reactions. But when it undergoes a physical change, it only needs to return to its original state of matter. The molecules of the substance haven’t been changed at all.
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TRUE OR FALSE equilibrium constant (Keq) is the ratio of the mathematical concentration products over reactants.
Answer: True
Explanation: The value of the equilibrium constant indicates whether or not a reaction is favorable. Reactions for which Keq is greater than one are favorable, meaning that the reactants are higher in energy than the products and signifying that energy is released as the reaction proceeds.
heat is transferred at a rate of 2 kw from a hot reservoir at 725 k to a cold reservoir at 300 k. calculate the rate at which the entropy of the two reservoirs changes. (round the final answer to six decimal places.) the rate at which the entropy of the two reservoirs changes is kw/k. is the second law satisfied?
the rate at which the entropy of the two reservoirs changes is 0.00390837931 kw/k .
What is entropy ?
Entropy, a measure of a system's thermal energy per unit temperature not available for useful work. Work is obtained from molecular motion, the amount of entropy is a measure of the molecular disorder or randomness of a system. The concept of entropy gives us deep insight into the direction of spontaneous change in many everyday phenomena. Introduced in 1850 by German physicist Rudolf Clausius, it is the pinnacle of 19th-century physics.
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according to dalton, if 6g of carbon react with 17 g of hydrogen, how many grams of carbon combine with 85 g of hydrogen?
Considering Dalton's theory 30 grams of Carbon combines with 85 grams of hydrogen.
Daltons theory is based on the law of conservation of mass and also the law of constant composition. The first part of his theory states that all matter is made up of atoms, and these atoms are indivisible. The second part of this theory says that atoms of a given element are identical in mass and also in properties. But it will be different only in case of different types of molecules present together.
According to Daltons theory if 6 grams of Carbon is reacting with 17 grams of Hydrogen then for 85 grams of Hydrogen the amount of carbon required will be
⇒ 6 × 85 = 30
17
Therefore 30 grams of Carbon is required to combine with 85 grams of Hydrogen.
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what is the voilume of a solution that would result by diluting 50.0 mlof 0.101 m naoh to a ocfncentration of 0.0505m
The volume of the solution that would result by diluting 0.1M solution to 0.05M is 100ml.
The molarity of the substance is defined as the number of moles of solute per unit volume of solution in liters.
Hence, if we can write,
Molarity = moles/volume
Moles = molarity x volume
Moles are always constant, so,
initial molarity x initial volume = final molarity x final volume
The initial volume is 50ml and initial molarity is 0.1M, after diluting, the final molarity is 0.05M.
Putting values,
50 x 0.1 = Volume of NaOH after dilution x 0.05
Volume of NaOH after dilution = 100 ml.
So, the volume of the resulting solution after dilution is 100ml.
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30.00 ml of a h2so4 solution with an unknown concentration was titrated to a phenolphthalein endpoint with 44.45 ml of a 0.1489 m naoh solution. what is the concentration of the h2so4 solution?
The concentration of the H2SO4 solution should be 0.1101 M.
Calculation of the concentration:
Since
Volume of H2SO4 = 30.00 mL = 0.030 L
Volume of NaOH= 44.45 mL = 0.04445 L
Concentration of NaOH= 0.1489 M
Now
The balanced equation is
H2SO4 + 2NaOH → Na2SO4 + 2H2O
Now the concentration of the H2SO4 solution is
b*Ca*Va = a*Cb*Vb
here, b = the coefficient of NaOH = 2
Ca = ?
Va = the volume of H2SO4= 30.0 mL = 0.030 L
a = the coefficient of H2SO4 = 1
Cb = the concentration of NaOH = 0.1489 M
Vb = the volume of NaOH = 44.45 mL = 0.04445 L
Now
2*Ca*0.030 = 1* 0.1489* 0.04445
0.060 * Ca = 0.00661
Ca = 0.1101 M
Hence, The concentration of the H2SO4 solution is 0.1101 M.
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3. if a nitrogen atom contains only single bonds to 2 h atoms and one cl atom, how many bonding electrons are assigned to the n atom when calculating the oxidation number?
There are 14 valence electrons assigned to the n atom.as it forms NH4CL lewis structure.
Lewis structure can be explained the bonding pair from the lone pair electrons.it shows non bonding electrons.hydrogen atom form one covalent bond.cl is anionic monoatomic ligand. H is a diatomic anionic ligand. Nitrogen is the least electronegative atom goes at the center.Hydrogen atoms always go on the outside of lewis structure.
In this, N has 5 valence electron.Hydrogen has 1 and cl has 7 valence electron.that gives total 14 valence electrons.cl has 3 lone pairs and n has a lone pair..
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What is the mass in grams of 5.90 mol C6H12?
The mass, in grams, of 5.90 mol [tex]C_6H_{12[/tex] would be 495.6 grams.
Number of moles of substanceThe number of moles in a given amount of substance is the ratio of the mass of the substance and its molar mass.
The statement of the number of moles of substances can be mathematically expressed as follows:
Mole = mass/molar mass
Making molar mass the subject, the equation becomes:
Molar mass = mass/mole
Making mass the subject, the equation becomes:
Mass = mole x molar mass.
In this case, we are looking for the mass of a given mole of [tex]C_6H_{12[/tex].
C = 12 g/mol
H = 1 g/mol
Molar mass of [tex]C_6H_{12[/tex] = (6x12) + (12x1)
= 72 + 12
= 84 g/mol
Hence:
Mass of 5.90 mol [tex]C_6H_{12[/tex] = 5.90 x 84
= 495.6 grams
In other words, 5.90 mol of [tex]C_6H_{12[/tex] would be equivalent to 495.6 grams of the compound.
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if you overshoot the endpoint of a titration in this experiment, it means you added too much of the titrant (naoh). if this happens without realizing it, and you measure the volume of naoh you added, what will happen to the value you calculate for the concentration of naoh?
The value calculated by using excess if NaOH by overshooting endpoint during titration will be not correct.
The value of concentration is supposed to change when excess of NaOH is used. it will be little too high than the correct value. Thus, titration require precise values. Overshooting the endpoint will result in a calculation error for the solution that is being titrated. The calculation for the titrated solution will be off if the moles of titrant are incorrect because the volume of titrant is incorrect because it is higher than it should be.
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how many atoms of sulfur are in 60.0 g of aluminum sulfide, al2s3? molar masses: al: 27.0 g/mol s: 32.1 g/mol
There are [tex]1.77 * 10^{24}[/tex] atoms of sulfur in 60.0 g of aluminum sulfide.
How do you calculate the number of atoms in a gram?
To get the answer in grams, divide the element's relative atomic mass by Avogadro's number. The same method can be used to determine a molecule's mass. Add up all the atomic masses in the chemical formula in this situation and divide by Avogadro's constant.What is the purpose of aluminum sulfide?
Hydrogen sulfide is made with the help of aluminum sulfur. The chemical industry uses it most frequently. It is employed in the production of cathodes. It is used to create structures for nano-networks.To learn more about Aluminum sulfide, follow the link https://brainly.com/question/5390765
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How many Hershey's Kisses are in 2 OWLS?
Answer:
20
Explanation:
owls are 10 of anything 10x 2 =20
It seems as though the value of the owl is up to you though
Hopes this helps
Which of the following descriptions apply to valence electrons?
Select all that apply.
They are electrons in the highest occupied principal energy level of an atom.
They participate in chemical bonds.
They do not determine how reactive an atom will be.
They must always be paired with another electron.
They were electrons in an atom's greatest primary energy level, which is occupied. In chemical bonds, they take part.
How do chemical bonds work?Atoms in molecules are held together by chemical bonds. Electrostatic forces between negatively charged electrons and positively charged atomic nuclei, whose locations in space are governed by quantum mechanics, give rise to bonds.
What makes chemical bonds so crucial?One of the most fundamental principles of chemistry, chemical bonding helps to explain other ideas like molecules and reactions. Without it, scientists would be unable to explain why atoms are drawn to one another or how products are created during a chemical process.
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Which of the following are spectator ions in the equation below? Select all that apply
Pb(C₂H302)2(ag) + 2 LiCl(ag) 2 LIC₂H302(ag) + PbCl2(s)
Pb2+(aq)
Li+(aq)
Cl-(aq)
C2H3O-2(aq)
I hope i entered the answer options right
given 5.86 moles of NaN3, how many moles of Na are produced?
When 5.86 moles of NaN3(Sodium Azide) is given then no. of moles of Na produced is 5.86 mol.
What is NaN3 (Sodium Azide)?The inorganic substance with the formula NaN3 is sodium azide. The gas-forming element in older automotive airbag systems is this colourless salt. It is utilised to make additional azide chemicals. It is an ionic chemical that is exceedingly water soluble and extremely dangerous.
What Na Describes?Na is the chemical formula used for the element having atomic number 11 and called as Sodium
Acc. to the given data following is the reaction occurring
2NaN3→2Na+3N2
Now to calculate the no. of moles of Na
Multiply the given moles of sodium azide(NaN3) by the mole ratio between NaN3 and N2 from the balanced equation, with Na in the numerator. 2 mol Na:3 mol N2
5.86 molNaN3×2mol Na/2mol NaN3=5.86 mol Na
Hence, when 5.86 moles of NaN3(Sodium Azide) is given then no. of moles of Na produced is 5.86 mol.
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Question 8(Multiple Choice Worth 4 points)
(01.04 LC)
What best describes a material's ability to dissolve?
O Solubility
O Melting point
O Boiling point
O Thermal conductivity
Answer:
Solubility is the best to dissolve
for the titration of 20.00 ml of 0.500 m hcl with 0.500 m naoh: (2.5 pts) a. write the equation for the reaction taking place during the titration: b. calculate the ph before the addition of naoh: c. calculate the ph after the addition of 10.00 ml of 0.500 m naoh: d. calculate the ph after the addition of 20.00 ml of 0.500 m naoh: e. calculate the ph after the addition of 20.20 ml of 0.500 m naoh:
(a) The balanced chemical equation is -
NaoH + Hcl - Nacl + H2O
(b) For the pH before addition of NaoH, we need
pH = log [H+]
= -log [0.5]
=-(-0.3)
=0.3
The pH of the solution before addition of NaoH is 0.3
(c) Mole of NaoH = 0.5 x 10 = 5molar
Mole of Hcl = 0.5 x 20 = 10mili molar
Unreacted moles of Hcl = 10 -5 = 5 moles.
Total volume = 20 +10 = 30 ml
Molarity = 5 moles / 30ml = 0.166
pH = -log (0.166) = 0.77
(d) Moles of NaoH = 20 X 0.5 = 10 milli molar.
Therefore, Hcl consumed = 10 milli mole.
pH of water = [H+] = 10^-7 molar.
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how many valence electrons does each of these four elements have? how do you know? a) aluminum (al), b) fluorine (f), c) sodium (na), and d) calcium (ca)
describe the experimental method through which you determine the appropriate wavelength for an analyte
Wavelength is chosen by analyzing the spectrogram.
Wavelength can be defined as the distance between two successive crests or troughs of a wave. It is measured in the direction of the wave.
A spectrogram gives a going for walks show of a sound signal because it takes place in real time, a spectrum, however, offers us a photograph of the sound at a particular factor in time. A spectrum can permit you to see.
Spectrograms map out sound in a comparable way to a musical rating, only mapping frequency rather than musical notes. Seeing frequency energy allotted over the years in this manner allows us to genuinely distinguish each of the sound factors in a recording, and their harmonic shape.
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how many grams of koh is required to produce 800 ml of 0.500 m naoh solution? enter the number only, not units
For every 800 ml of 0.500 m potassium oxide solution, one gramme of potassium hydroxide is needed.
The following knowledge is necessary to answer the question:
KOH has a molar mass of 56u.
Molarity is defined as Mass of Solute multiplied by 1000 or (Molar mass of Solute divided by mL of Solution).
Given are the values M=0.4 and V=800mL.
The formula yields the following result: 0.5 = Mass of KOH 1000/(56 800).
When it is solved, 8 grammes of KOH are required.
Molar mass simple: What is it?The molar mass of a substance is the weight of one mole of that substance, how many grammes are contained in one mole of a specific chemical is what is meant by the term "molar mass." The atomic masses used to calculate the molar mass are given in the periodic table.
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The reaction below is known as the Thermitt reaction, which is used to form molten iron to mould train tracks
together. What mass of aluminium powder is needed to react with 8.00 g of iron (III) oxide?
2 Al + Fe₂O3 —-> Al₂O3 + 2 Fe
2 Al&3irons with 2fe and 36copper
A student was asked to formulate a hypothesis about what would happen if 100. mL of 0.1 M NaOH(aq) at
25°C was combined with 100. mL of 0.1 M MgCl₂(aq) at 25°C. Which of the following hypotheses indicates
that the student thought a chemical change would occur?
Answer:
There will be the formation of a Common salt (NaCl) and Mg(OH)2 which is a base after the reaction between the two chemicals
A scientist has 4 pieces of copper. Each piece is a different shape and size (samples A 1 p through D). The student measures the volume and the mass of one sample, but measures only the volume or only the mass of the other samples. Since the scientist knows that copper is a substance, the scientist claims that she can predict what the mass will be of sample B and C. She also claims she can predict what the volume will be of sample D. Use the table below to calculate the MASS OF SAMPLE. Type ONLY THE NUMBER in the space below.
The value of the mass (B) will be equal to 9 grams and volume (D) will be equal to 5 cm^{3}.
What is density ?
Density is the degree of ways much “stuff” is in a given quantity of space. For example, a block of the heavier detail lead could be denser than the softer, lighter detail gold (Au). A block of Styrofoam is much less dense than a brick. It is described as mass in line with unit volume.
You can consider it, as how tightly or loosely packed a substance is, or how compact it is. Solids are commonly denser than beverages, and beverages denser than gases, however there are numerous exceptions.
Density is a bodily assets of matter, as every detail and compound has a completely unique density related to it. Density described in a qualitative way because the degree of the relative "heaviness" of gadgets with a regular volume.
Copper's Density is nearly equal to 9 and density is equal to mass/volume.
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How many ml of a 14.0 m nh3 stock solution are needed to prepare 200 ml of a 4.20 m dilute nh3 solution?
60 ml of a 14.0 M NH₃ stock solution are needed to prepare 200 mL of a 4.20 M dilute NH₃ solution.
Using the formula given below ,
M₁ x V₁ = M₂ x V₂
M₁ = concentration of stock solution
V₁ = volume of stock solution (to be found out)
M₂ = concentration of diluted solution
V₂ = volume of diluted solution;
V₁ = (M₂ x V₂) / M₁
= (4.2 x 200) / 14
= 60ml
Hence , 60 ml of a 14.0 Mole NH₃ stock solution are needed to prepare 200 mL of a 4.20 M dilute NH₃ solution.
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a sample of ethanol, c2h6o, has a mass of 72.75 g. calculate the number of ethanol molecules in the sample
The number of ethanol molecules in the sample are
The molecular mass of ethanol is 45.07 g/mol
Now to calculate the number of molecules of ethanol:
72.75 × (1 mol/46.07)
1.5 moles
Now multiply it with by Avogadro's number which is 6.02 X 10^23 molecules / mole.
1.5 × 6.02 X 10^23
9.03 X 10^23 molecules.
Hence the number of ethanol molecules in the sample 9.03 X 10^23 molecules.
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boron has two isotopes; boron-10 and boron-11. which is more abundant, given that the atomic mass of boron is 10.81?
Given that boron has an atomic mass of 10.81 amu, which is closer to 11 than 10, boron-11 is more common. This indicates that boron-11 is more prevalent.
What is atomic mass ?The quantity of protons and neutrons in a specific element's nucleus is known as the atomic mass. This number of electrons in an object's nucleus is often indicated by its atomic number. It is an element's typical weight. The mass of the neutrons and protons can be added to determine the isotopes of an atom in an element.
Why do we use atomic mass?The term "atomic mass" refers to the weight of a molecule or atom. To determine the average weight of elements and macromolecules as well as to resolve stoichiometry issues, the number of protons is used.
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Rationalize the order of elution of the two compounds you isolated from the column in this experiment.
Hexane is initially employed as the eluting solvent to remove the bibenzyl. The bibenzyl will be eluted first because the nonpolar molecule is particularly soluble in hexane (a nonpolar solvent) .
What is called a compound?A mixture in chemistry is a material comprised of two or more separate chemical elements mixed together in a certain proportion. Chemical connections that are challenging to break are created when the components interact with one another. These bonds result in the development of atoms sharing or trading electrons.
Is an element a compound?Pure components and compounds can be found in nature. A element is formed up of many elements in a predetermined ratio, as opposed to an element, which is a substance comprised of the same sort of atoms.
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What is the mass in gram of carbon atoms in 4.4g of C3H8 ?
Help ASAP
I'LL MARK BRAINLIEST
determine the volume in ml of a 0.505 m naoh solution required to titrate 40 ml of 0.25 mh2 so4 solution
The volume of required NaOH is 39.6 ml
What is normality?According to the standard definition, normality is expressed as the number of grams or molar equivalents of solute present in one liter of solution. When we say equivalent, this is the number of moles of reactive moieties in the compound.
Base acidity describes the number of ionizable hydroxide groups in the base. NaOH has an ionizable hydroxide group. Hence, the normality of NaOH is 0.5125 N.
For the given case,
N₁V₁ = N₂V₂
Normality = Molarity × Basicity
For H₂SO₄ the basicity is 2
N₂ = 0.25 × 2
= 0.5 N
For NaOH the acidity is 1
N₁ = 0.505 × 1
= 0.505 N
N₁V₁ = N₂V₂
0.505 × V₁ = 0.5 × 40
V₁ = 39.6 ml
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