Answer:
Constant-volume molar heat capacity of argon is 12.47 J K ⁻¹mol⁻¹
Explanation:
Argon is a monoatomic gas that behaves as an ideal gas at 298K.
Using the first law of thermodinamics you can obtain:
Work, Q, for constant pressure molar heat capacity,CP:
CP = (5/2)R
For constant-volume molar heat capacity,CV:
CV = (3/2)R
That means:
2CP/5 = 2CV/3
3/5 = CV / CP
As CP of Argon is 20.79 J K ⁻¹mol⁻¹, CV will be:
3/5 = CV / CP
3/5 = CV / 20.79 J K ⁻¹mol⁻¹
12.47 J K ⁻¹mol⁻¹ = CV
Constant-volume molar heat capacity of argon is 12.47 J K ⁻¹mol⁻¹Explain with examples following characteristics of chemical reactions: a. Change of colour b. Evolution of gas c. Change of smell d. Change of state
Answer:
Explanation:
a. change of colour:
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. The products have different molecular structures than the reactants. Different atoms and molecules radiate different colours of light. Hence, there usually is a change in colour during a chemical reaction.
Eg: copper reactions with the elements
b. Evolution of gas:
A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide.
Eg: ammonium hydroxide breaks down to water and ammonia gas.
c. Change of smell :
Production of an Odor Some chemical changes produce new smells. ... The formation of gas bubbles is another indicator that a chemical change may have occured.
Eg: The chemical change that occurs when an egg is rotting produces the smell of sulfur.
d. Change of state:
A chemical reaction is a process in which one or more substances, also called reactants, are converted to one or more different substances, known as products.
Eg: candle wax (solid) melts initially to produce molten wax (liquid)
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If an electromagnetic wave has a frequency of 4.5 x 10^18 Hz, what is its wavelength? The speed of light is 3 x 108 m/s.
Answer:
Wavelength, λ = 6.7 x 10^-11 m
Explanation:
Frequency and wavelength are inversely proportional to each other.
In this problem;
f = 4.5 x 10^18 Hz
wavelength, λ = ?
Speed of light, c = 3 x 108 m/s.
These variables are related by the following equation;
c = λ * f
Making λ subject of focus, we have;
λ = c / f
λ = 3 x 10^8 / 4.5 x 10^18
λ = 0.67 x 10^-10
λ = 6.7 x 10^-11 m
How many oxygen molecules are needed to make 10 carbon dioxide molecules according to the following balanced chemical equation? 2 CO + O2 → 2 CO2
five oxygen molecules
step by step explanation.
according to the equation,one molecule of oxygen is enough to react with two carbon molecules thus 10 carbon molecules need 5oxygen molecules
A compound consisting of atoms of small atomic mass is more likely to require what
Answer:
a lower temperature to liquefy
Explanation:
The mathematics of combining quantum theory with wave motion of atomic particles is known as _____.
Combining quantum theory with wave motion of atomic particles is: Wave Mechanics
(-)-Cholesterol has a specific rotation of -32o. A mixture of ( )- and (-)-cholesterol was analyzed by polarimetry, and the observed rotation was 14o. What is the percent composition of the ( ) isomer in this mixture
Answer:
(+)-cholesterol = 71.88%
(-)-cholesterol = 28.12%
Explanation:
Asuming 1 gram of sample is dissolved in 1mL of water and the sample cell was 1dm long.
Enantiomeric excess is defined as the amount of pure enantiomer in a sample. The formula is:
ee = [α]mixture / [α]pure enantiomer.
Replacing:
ee = 14° / 32°×100 = 43.75%
As the sample is 14°, There is an excess of (+)-cholesterol and 56.25% is a 1:1 mixture of enantiomers.
That means percent composition of enantiomers is:
(+)-cholesterol = 43.75% + 56.25%/2 = 71.88%(-)-cholesterol = 56.25%/2 = 28.12%How many water molecules are in a block of ice containing 1.25 mol of water (H2O)
Answer:
Molecules = 7.5 × 10²³ molecules
Explanation:
Given:
Moles = 1.25 mol
Avogadro's No. = [tex]N_{A}[/tex] = 6.022 * 10²³
Required:
Molecules = ?
Formula:
Molecules = Moles × [tex]N_{A}[/tex]
Solution:
Molecules = 1.25 × 6.022 × 10²³
Molecules = 7.5 × 10²³ molecules
The lock and key model and the induced fit model are two models of enzyme action explaining both the specificity and the catalytic activity of enzymes. Indicate whether each statement is part of the lock and key model, the induced fit model, or is common to both models.
a. Enzyme conformation changes when it binds the substrate so the active site fits the substrate
b. Substrate binds to the enzyme at the active site, forming an enzyme-substrate complex
c. Enzyme active site has a rigid structure complementary
d. Substrate binds to the enzyme through noncovalent interactions
Answer:
"The active site of the enzyme has a complementary rigid structure" belongs to the key and lock system
"The conformation of the enzyme changes when it binds to the substrate so that the active site conforms to the substrate." belongs to the induced fit system.
"The substrate binds to the enzyme at the active site, forming an enzyme-substrate complex" belongs to both, that is, the key and lock system and the induced fit system.
"The substrate binds to the enzyme through non-covalent interactions" can belong to both enzyme systems.
Explanation:
Enzymatic key and lock systems bear this name because the enzyme at its site of union with the substrate has an ideal shape so that its fit is perfect, similar to a headbreaker, so once they are joined they are not It can bind another substrate to the enzyme, since they are generally associated with strong chemical bonds.
The shape of the enzyme's active site is a negative of what the shape of the substrate would be.
On the other hand, in the mechanism or enzyme system of induced adjustment, the enzyme has an active site that is where it binds with the substrate and another site where another chemical component binds, which when this chemical component binds this enzyme changes its morphology and becomes "active" to bond with your substrate.
This happens a lot in the inactive enzymes that are usually activated in digestive processes since the fact that these enzymes are constantly active would be dangerous, therefore the body takes the induced enzyme system as a control mechanism, where a molecule or chemical compound induces change morphological of an enzyme by means of the allosteric union so that it joins its substrate and catalyzes or analyzes it, depending on the enzymatic character of the enzyme.
Identify the particle that must receive 2 electrons to acquire a charge of +1. a) K b) Fe2+ c) O2- d) Nee) Al3+ (URGENT) Needs to be done in 30 mins
Answer:
E) Al³⁺
Explanation:
A reaction involving a gain of electrons is known as a reduction reaction because the oxidation number of the species gaining the electron is reduced.
In the given question, the oxidation number (charge) of particle accepting two electrons will decrease by 2. From the given options;
A. K is a neutral atom with oxidation number of 0. If is accepts two electrons, its oxidation number becomes -2.
K + 2e⁻ ----> K⁻²
B) Fe²⁺ has a charge of +2. If it accepts two electrons, its charge comes 0.
Fe⁺ + 2e⁻ ----> Fe
C) O²⁻ has a charge of -2. if it accepts two electrons, it will have a charge of -4.
O²⁻ + 2e⁻ ----> O⁴⁻
D) Ne has a charge of zero. If it accepts two electrons, its charge becomes -2.
Ne + 2e⁻ ----> Ne²⁻
E) Al³⁺ has a charge of +3. If it gains two electrons, its charge becomes +1.
Al³⁺ + 2e⁻ ----> Al⁺
Which element's neutral atoms will have the electron configuration
1s22s22p3s23p'?
a. boron
b. carbon
c. silicon
d. aluminum
Answer:
Alumunium
Explanation:
Alumunium = [Ne] 3s² 3p¹
Ne = [He]2s²2p⁶
He = 1s
Alumunium = 1s 2s²2p⁶3s² 3p¹
Answer:
D
Explanation:
g Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 1.94 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 23.82 mL. What volume of base was required for the titration
Answer:
21.88mL is the volume of base required for the titration.
Explanation:
For an acid-base titration trying to find the concentration of an acid, you must add a known quantity of the acid and titrate it with an standarized base.
If you know the moles of base you add to the acid solution, these moles are equal to moles of acid.
In the buret of the titration, initial volume is 1.94mL and final volume is 23.82mL. The volume you are adding is the difference between initial and final volume, that is:
23.82mL - 1.94mL
21.88mL is the volume of base required for the titration.Why Graphite is Diamagnetic?
Answer: Through years of studying and research ;
Graphite has shown that in weak and quantizing magnetic fields it is material is a highly anisotropie diamagnetic substance whose non-oscillating part of the magnetic suscepti- bility weakly depends on magnetic field.
Explanation:
Diamagnetism is a (very) weak form of magnetism which is caused (induced) by a change in the orbital motion of electrons mostly due to an applied magnetic field.
Which element has the largest atomic radius
Answer:
Francium
Explanation:
The atomic radius increases from top to bottom in a group, and decreases from left to right across a period.
so francium (Fr) is the largest atom or has highest radii.
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Answer:
Francium has the largest atomic radius.
The general trend for atomic radii is increasing from top to bottom and decreasing from left to right so the one with the largest atomic radius will be in the bottom left of the periodic table.
How many moles of carbon atoms are there in 0.500 mol of C2H6?
The number of moles of carbon atoms in 0.500 mol of ethane (C₂H₆) is equal to one mole.
What is a mole?A mole can be defined as a scientific unit that is utilized to calculate the quantities such as atoms, molecules, ions, or other particular particles. The mass of one mole of a given chemical element is atomic mass and that of 1 mole of a chemical compound is molar mass.
The number of entities found in one mole is equal to 6.023 × 10 ²³ which is known as Avogadro’s constant.
Given, the number of moles of C₂H₆ = 0.500 mole
One molecule of ethane has carbons = 2
One mole of ethane has moles of carbons = 2 moles
0.500 mol of ethane has moles of carbon atoms = 0.500×2 = 1 mol
Therefore, one mole of carbon atoms is present in 0.500 mol of ethane C₂H₆.
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A cylindrical rod of length 1 m and radius 1 cm is submerged in water. The rod has a non-uniform mass distribution such that one half of the rod is much more massive than the other half. At which point in the rod can the buoyant force be considered to be acting?
A) at the rod's geometrical center
B) two of the given choices are correct
C) none of these
D) at the rod's center of mass
E) at the rod's center of gravity
Answer:
A) at the rod's geometrical center
Explanation:
Let us assume that the rod is replaced by water. And now this water volume is in translational and in rotational equilibrium.
Therefore, a net upward force must have been exerted by the surrounding liquid which acts at the center of mass of the water volume.
This force determines through the geometric center of the column of the cylindrical water
Moreover, the force is also independent of submerged body into it
Hence, the first option is correct
Identify which of the following are carbohydrates.
Check oh that apply
Answer:
3d and 4th
Explanation:
Carbohydrates general formula (CH2O)n.
Not 1st one because it has NH2-group.
2nd - C3H6O4, also it is acid.
3d - C3H6O3
4th - C6H12O6
Among the given compounds only compound present in 3rd option is a carbohydrate.
What are carbohydrates?Carbohydrates are the organic molecules which are made up of oxygen atom, carbon atom and hydrogen atom and general molecular formula of carbohydrates is CₙH₂ₙOₙ, where n is the number of atoms.
In the carbohydrate molecule, alcoholic group and aldehyde groups may present.
First given compound is not a carbohydrates as in that NH₃ group is present.Second given compound is also not a carbohydrate as in that carboxylic (-COOH) group is present.Third compound is a carbohydrate as in that compound same number of carbon and oxygen atoms are present and number of hydrogen atom is double to C & O atom.Fourth compound is also not a carbohydrate, as in that molecule number of carbon and oxygen atom is same but number of hydrogen is not double with respect to C & O.Hence compound C is carbohydrate.
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Answer:
Path A-B-D involves a catalyst and is slower than A-C-D
Explanation:
The diagram above illustrates both the catalyzed path and the uncatalyzed path of a chemical reaction.
The catalysed path is the path expressed with broken lines and the uncatalyzed path is the path expressed with thick small line as shown in the diagram above.
The catalyzed path has a higher activation energy than the uncatalyzed path.
Therefore, the catalyzed path will be slower that the uncatalyzed path because, the catalyzed path will require a higher energy to overcome the activation energy in order for the reaction to proceed to product.
On the other hand, the uncatalyzed path has a lower activation energy and a lesser amount of energy is needed to overcome it in order for the reaction to proceed to product.
A solid white substance A is heated strongly in the absence of air. It decomposes to form a new white substance B and a gas C. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen. Based on these observations, can we determine whether solids A and B and the gas C are elements or compounds?
Answer:
A, B and C are compounds
Explanation:
First of all, I need to establish that when carbon is burnt in excess oxygen, carbon dioxide is obtained as shown by this equation; C(s) + O2(g) ----> CO2(g).
Looking at the presentation in the question, A was said to be heated strongly and it decomposed to B and C. Only a compound can decompose when heated. Elements can not decompose on heating. Secondly, compounds usually decompose to give the same compounds that combined to form them. Compounds hardly decompose into their constituent elements.
Again from the information provided, the compound A is a white solid. This is likely to be CaCO3. It decomposes to give another white solid. This may be CaO and the gas was identified as CO2.
Hence;
CaCO3(s)--------> CaO(s) + CO2(g)
1. Corrosion in metals is an example of what?
Answer:
In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen or sulfates. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion.The basic function of a carburetor of an automobile is to atomize the gasoline and mix it with air to promote rapid combustion. As an example, assume that 30 cm3 of gasoline is atomized into N spherical droplets, each with a radius of 2.0 × 10−5 m. What is the total surface area of these N spherical droplets? Answer: [A] m2.
Answer:
The total surface area of these N spherical droplets is 4.4929 m²
Explanation:
From the information given :
assuming that :
30 cm³ of gasoline is atomized into N spherical droplets &
each with a radius of 2.0 × 10−5 m
We are tasked to determine the total surface area of these N spherical droplets
We all known that:
[tex]1 \ cm^3 = 10 ^{-6} m^3[/tex]
Therefore
[tex]30 \ cm^3 = 30 * 10 ^{-6} m^3 = 3 *1 0^{-5} \ m^3[/tex]
For each droplet; there is a required volume which is = [tex]\dfrac{4}{3} \pi r ^3[/tex] since it assumes a sphere shape .
Thus;
replacing radius(r) with 2.0 × 10−5 m; we have:
[tex]= \dfrac{4}{3} \pi * (2.0 *10^{-5} m) ^3[/tex]
= [tex]3.35 * 10^{-14} \ m^3[/tex]
However; there are [tex]3*10^{-5} \ m^3[/tex] gasoline atomized into N spherical droplets with each with radius 2.0 × 10−5 m
For N ; we have ;
[tex]=\dfrac{3*10^{-5} \ m^3}{3.35 * 10^{-14} \ m^3/ droplet}[/tex]
= [tex]8.95*10^8 \ droplet s[/tex]
So; each droplet have a surface area = [tex]4 \pi r^2[/tex]
= [tex]4 \pi (2.0*10^{-5}m) ^2[/tex]
= [tex]5.02*10^{-9} \ m^2/droplets[/tex]
The surface area per droplet is equivalent to [tex]5.02*10^{-9} \ m^2/droplets[/tex]
Thus;
The total surface area of these N spherical droplets will be :
= [tex]8.95*10^8 \ droplet s * 5.02*10^{-9} \ m^2/ droplets[/tex]
= 4.4929 m²
The total surface area of these N spherical droplets is 4.4929 m²
Kinetic energy and gravitational potential energy are both forms of which type
of energy?
A. Internal energy
B. Mechanical energy
C. Potential energy
D. Thermal energy
Answer:
C. Potential energy
Explanation:
Kinetic energy and gravitational potential energy are both forms of potential energy. Potential energy is stored energy, when an object is not in motion it has stored energy. When an object is an motion it has kinetic energy. An object posses gravitational potential energy when it is above or below the zero height.
A gas contained in a steel tank has a volume of 1.5 L at a temperature of 390 K. What will be the volume when the temperature changes to 1470C? Group of answer choices
Answer:
1.5 L
Explanation:
If the gas is contained in a steel tank, the volume will remain constant when the temperature changes.
The volume will be 1.5 L.
Write the empirical formula
Answer:
[tex]Pb(CO_{3})_{2} \\Pb(NO_{3})_{4} \\FeCO_{3}\\Fe(NO_{3})_{2}[/tex]
Explanation:
[tex]Pb^{4+}(CO_{3}^{2-})_{2} --->Pb(CO_{3})_{2} \\Pb^{4+} (NO_{3}^{-})_{4} --->Pb(NO_{3})_{4} \\Fe^{2+} CO_{3}^{2-} --->FeCO_{3}\\Fe^{2+} (NO_{3}^{-})_{2}--->Fe(NO_{3})_{2}[/tex]
Cual es la diferencia entre agua pesada y agua ligera a) el agua pesada contiene mas minerales que el agua ligera b) el agua ligera es liquida mientras el agua pesada es solida c) el agua ligera es agua purificada y el agua pesada es agua contaminada d) el agua pesada contiene mas elementos estearato de sodio
Answer:
d) El agua pesada contiene mas elementos
Explanation:
La diferencia fundamental entre el agua pesada y el agua ligera es que la primera tiene una proporción mayor de deuterio que la segunda. El deuterio es un ión del hidrógeno que tiene un peso atómico mayor que el hidrógeno común y corriente. Por ende, la opción D ofrece la mejor aproximación.
Answer:
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Explanation:ki
when dissolved in water, an acid or a base breaks down into a. a proton and an electron b. two negative ions c. a positive and a negative ion d. a positive ion and a proton
Answer:
C. A positive and a negative ion
Explanation:
Acids and bases are made up of charged particles known as ions. The ions present in acids are oppositely charged and are held together by strong electrostatic forces. When acids or bases are dissolved in water, the electrostatic forces holding their individual molecules together are weakened and these ions are free to move apart in a process known as dissociation. Dissociation occurs because of the attraction between the positive and negative ions in the acid and bases and the negative and positive polarity of water.
For example, when an acid like hydrochloric acid is dissolved in water it dissociates into positive and negative ions as follows:
HCl(aq) -----> H+ + Cl-
When a base like sodium hydroxide is dissolved in water, it dissociates into positive and negative ions as follows:
NaOH(aq) ----> Na+ + OH-
Answer:
yeah C is correct
Explanation:
what is the molarity of a solution that contains 49.8 grams of nai and is dissolved in enough water to make 1.50 liters
Answer: The molarity of solution is 0.221 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in L
moles of [tex]NaI[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{49.8g}{149.89g/mol}=0.332mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]Molarity=\frac{0.332mol}{1.50L}[/tex]
[tex]Molarity=0.221mol/L[/tex]
Therefore, the molarity of solution is 0.221 M
Identify the precipitation reaction in the set?
Answer:
The third reaction
(2NaOH + NiCL2 ---> 2NaCl + Ni(OH)2)
Explanation:
By definition, a precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined.
(Source: lumenlearning)
From the 4 options, we can eliminate the first and second one immediately because there is no formation of an insoluble salt.
Then, the last one can also be eliminated because even though there is insoluble solid formed, but it is not a salt, and, the reactants are not solutions too. In fact, the last one is a displacement reaction. A more reactive metal displaces a less reactive metal to form an ion.
Since the third reaction matches the definition of precipitation reaction, this is the answer.
A naturally occurring oil co-distills with water to produce an oil/water distillate that is 20% oil by weight. If the molecular weight of the oil 100 g/mol, what was the partial pressure of the oil during distillation assuming atmospheric pressure is 760 mm Hg
Answer:
Explanation:
Partial pressure of oil = mole fraction of oil x total pressure
mole fraction of oil = mole of oil / mole of water + mole of oil
= mole of oil = mass of oil / molecular weight of oil
= 20 / 100 = .2
mole of water = 80 / 18
= 4.444
mole fraction of oil = .2 / .2 + 4.444
= .2 / 4.644
Partial pressure of oil = mole fraction of oil x total pressure
= (.2 / 4.644 ) x 760 mm
= 32.73 mm Hg .
A 3.00-g sample of an alloy (containing only Pb and Sn) was dissolved in nitric acid (HNO3). Sulfuric acid was added to this solution, which precipitated 2.93 g of PbSO4. Assuming that all of the lead was precipitated, what is the percentage of Sn in the sample? (molar mass of PbSO4 = 303.3 g/mol)
Answer:
33.3% of Sn in the sample
Explanation:
The addition of SO₄⁻ ions produce the selective precipitation of Pb²⁺ to produce PbSO₄.
Moles of PbSO₄ (molar mass 303.26g/mol) in 2.93g are:
2.93g ₓ (1mol / 303.26) = 9.66x10⁻³ moles PbSO₄ = Moles Pb²⁺.
As molar mass of Pb is 207.2g/mol, mass in 9.66x10⁻³ moles of Pb²⁺ is:
9.66x10⁻³ moles of Pb²⁺ ₓ (207.2g / mol) = 2.00g of Pb²⁺
As mass of the sample is 3.00g, mass of Sn²⁺ is 3.00g - 2.00g = 1.00g
And the percentage of Sn in the sample is:
1.00g / 3.00g ₓ 100 =
33.3% of Sn in the sampleA silver cube with an edge length of 2.42 cm and a gold cube with an edge length of 2.75 cm are both heated to 85.4 ∘C and placed in 112.0 mL of water at 20.5 ∘C . What is the final temperature of the water when thermal equilibrium is reached?
Answer:
Explanation:
Volume of silver cube = 2.42³ = 14.17 cm³
mass of silver cube = volume x density
= 14.17 x 10.49 = 148.64 gm
Volume of gold cube = 2.75³ = 20.8 cm³
mass of gold cube = 20.8 x 19.3 = 401.44 gm
specific heat of silver and gold are .24 and .129 J /g°C
mass of 112 mL water = 112 g
Heat absorbed = heat lost = mass x specific heat x temperature fall or rise
Heat lost by metals
= 148.64 x .24 x ( 85.4 -T) + 401.44 x .129 x ( 85.4 - T )
= (35.67 + 51.78 ) x ( 85.4 - T )
87.45 x ( 85.4 - T )
= 7468.23 - 87.45 T
Heat gained by water
= 112 x 1 x ( T - 20.5 )
= 112 T - 2296
Heat lost = heat gained
7468.23 - 87.45 T = 112 T - 2296
199.45 T = 9764.23
T = 48.95° C