Final answer:
Rubbing alcohol molecules as a gas have the same structure as in the liquid but with more kinetic energy and less intermolecular attraction, which upon evaporation causes a cooling effect through evaporative cooling.
Explanation:
When rubbing alcohol evaporates from your hand, it leaves a cooling sensation because the molecules in the liquid state require a certain threshold of kinetic energy to overcome intermolecular forces and escape into a gas state. The correct statement regarding how the molecules of gas compare to the molecules as a liquid is:
The gas and liquid particles have the same structure and identity but different motion and kinetic energy.In the gaseous state, particles move faster and are further apart compared to when they are in the liquid state, where particles are closer together and have stronger intermolecular attractions. This process of evaporation involves evaporative cooling, where the molecules with higher kinetic energy escape, leaving behind those with lower kinetic energy, which results in a decrease in temperature.
What is the percent by mass of potassium in K3Fe(CN)6?
Answer:
The percentage of potassium in the given complex is 35.54 %.
Explanation:
Mass of potassium in [tex]K_3Fe(CN)_6[/tex] = 3 × 39.10 g mol=117.3 g/mol
Molar mass of [tex]K_3Fe(CN)_6[/tex] =329.15 g/mol
Percentage of potassium (K) in the the complex:
[tex]\% K=\frac{\text{mass of potassium}}{\text{molar mass of complex}}\times 100[/tex]
[tex]\%K=\frac{117.3 g/mol}{329.15 g/mol}\times 100=35.54\%[/tex]
The percentage of potassium in the given complex is 35.54 %.
what is the temperature of 12.2 moles gas in a 18.35 l tank at 16.4 atm? express in K and C.
The temperature of 12.2 moles gas in a 18.35 l tank at 16.4 atm is 3,071.7 K or 2,798.5 degree celsius.
How do we calculate temperature?Temperature of the gas will be calculated by using the ideal gas equation as:
PV = nRT, where
P = pressure of gas = 16.4 atm
V = volume of gas = 18.35 L
n = moles of gas = 12.2 mol
R = universal gas constant = 0.0821 L.atm / K.mol
T = temperature of the gas = ?
On putting all these values on the above equation, we get
T = (167.4)(18.35) / (12.2)(0.0821) = 3,071.7 K = 2,798.5 degree celsius.
Hence required temperature is 3,071.7 K or 2,798.5 degree celsius.
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Add formal charges to each resonance form of hcno below.based on the formal charges you added above, which structure is favored?
Answer:
The second structure is the most stable of all three.
Explanation:
The Formal Charge in the different resonance structures of HCNO is,
[tex]\rm FC=V-N+B[/tex]
Where,
FC- Formal charge
V- Valence Electron
N- Non-bonding Electron
B- Number of bonds
So, Formal charge In the atoms of first resonance structure is
H = 1-0+1=0
C = 4 -4+2 = -2
N = 5 - 0+4 = 1
O = 6 - 2 + 3 = 1
Formal charge In the atoms of Second resonance structure is
H = 1-0+1 = 0
C = 4 - 0 + 4 =0
N = 5 - 0 + 4 = 1
O = 6 - 6+1 = -1
Formal charge In the atoms of Third resonance structure is
H = 1-0 + 1 = 0
C = 4 - 2 +3 = -1
N = 5 - 0 + 4 = 1
O = 6 - 4 +2 = 0
To Figure out the most stable resonance structure we have to keep two things in mind:
1) The stable molecular structure tend to have the least number of charged atom.
2) In a stable molecular structure the negative charge is present in the more electronegative atom.
Here decreasing order of electronegativity is,
N > O > C > H
From the Explanation above, the second structure (B) follows both points
Therefore, The second structure is the most stable of all three.
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Look up the boiling points of anisole and d-limonene. which one do you expect to elute first in gas chromotograpjhy
Final answer:
In gas chromatography, compounds elute based on their boiling points, with those having lower boiling points eluting first. Since anisole has a lower boiling point than d-limonene, anisole is expected to elute first.
Explanation:
The question asks which compound, anisole or d-limonene, would elute first in gas chromatography (GC) based on their boiling points. In gas chromatography, compounds generally elute in order of increasing boiling points because compounds with lower boiling points have lower retention times on the GC column. Also, the elution order correlates with the strength of intermolecular forces (IMFs) affecting the compounds; compounds with stronger IMFs tend to have higher boiling points and adhere more to the stationary phase, thus eluting later. Although the specific boiling points of anisole and d-limonene are not provided in this answer, it is known that anisole has a boiling point of about 154°C, and d-limonene has a boiling point around 176°C. Therefore, one would expect anisole to elute first in gas chromatography due to its lower boiling point compared to d-limonene.
What is the expected oxidation state for the most common ion of element 2
Determine the empirical formula of a compound that contains 49.4% k, 20.3% s and 30.3% o.
How many moles of caco3 are there in an antacid tablet containing 0.515 g caco3?
Answer:
[tex]0.00515molCaCO3[/tex]
Explanation:
Hello,
By following the down below simple mass-mole relationship, the requested moles are computed, considering that the calcium carbonate has a molecular mass of 100g/mol:
[tex]M_{CaCO3}=40+12+16*3=100g/mol\\\\n_{CaCO3}=0.515gCaCO3*\frac{1molCaCO3}{100gCaCO3}=0.00515molCaCO3[/tex]
Best regards.
Final answer:
To calculate the number of moles of CaCO₃ in a 0.515 g antacid tablet, divide the mass of the CaCO₃ by its molar mass, yielding approximately 0.005144 moles of CaCO₃.
Explanation:
To find the number of moles of CaCO₃ in an antacid tablet containing 0.515 g of CaCO₃, we need to use the molar mass of CaCO₃. The molar mass of CaCO₃ (calcium carbonate) is approximately 100.09 g/mol. To calculate the moles, we divide the mass of the sample by its molar mass.
The calculation is as follows:
Mass of CaCO₃ = 0.515 gMolar mass of CaCO₃ = 100.09 g/molNumber of moles = Mass / Molar massNumber of moles = 0.515 g / 100.09 g/mol = 0.005144 molesTherefore, there are approximately 0.005144 moles of CaCO₃ in the antacid tablet.
Which acid is the best choice to create a buffer with ph= 7.66?
Carbonic acid is a polyprotic acid. write balanced chemical equations for the sequence of reactions that carbonic acid can undergo when it's dissolved in water.
The sequence of dissociation reactions of carbonic acid is a follows:
[tex]\text{Step\;1:\;}\text{H}_2\text{CO}_3(aq)+\text{H}_2\text{O}(aq)\overset{\text{K}_{al}}\leftrightharpoons\text{HCO}_3^-(aq)+\text{H}_3\text{O}^+(aq)\\\text{Step\;2:\;}\text{H}_2\text{CO}_3^-(aq)+\text{H}_2\text{O}(aq)\overset{\text{K}_{al}}\leftrightharpoons\text{CO}_3^2\;(aq)+\text{H}_3\text{O}^+(aq)[/tex]
Further Explanation:
An acid is a substance that is able to donate a proton or hydrogen ion [tex]\left( {{{\text{H}}^ + }} \right)[/tex] in aqueous solutions. Hydrochloric acid (HCl), sulphuric acid [tex]\left( {{{\text{H}}_2}{\text{S}}{{\text{O}}_4}} \right)[/tex] and nitric acid [tex]\left( {{\text{HN}}{{\text{O}}_3}} \right)[/tex] are some examples of acids. On the basis of the number of protons an acid can donate, acids can be monoprotic or polyprotic.
Acids that can donate just one proton in aqueous solutions are called monoprotic acids. For example, HCl, [tex]{\text{HN}}{{\text{O}}_{\text{3}}}[/tex] and [tex]{\text{C}}{{\text{H}}_3}{\text{COOH}}[/tex] are monoprotic acids as these can donate only one proton in solutions.
Polyprotic acids can donate more than one proton in aqueous solutions. These can further be divided as diprotic, triprotic and so on. Diprotic acids are the ones that can donate two protons in solutions. For example, [tex]{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex] and [tex]{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}[/tex] are diprotic acids. Triprotic acids are capable to donate three protons in solutions. For example, [tex]{{\text{H}}_{\text{3}}}{\text{As}}{{\text{O}}_{\text{4}}}[/tex] and [tex]{{\text{H}}_3}{\text{P}}{{\text{O}}_4}[/tex] are triprotic acids.
Carbonic acid has the chemical formula of [tex]{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex]. So it dissociates into an aqueous solution, releasing protons or hydrogen ions in it. Since carbonic acid is a diprotic acid, its dissociation takes place in two steps.
Step 1: The first dissociation of [tex]{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex] occurs as follows:
[tex]\text{H}_2\text{CO}_3(aq)+\text{H}_2\text{O}(aq)\overset{\text{K}_{al}}\leftrightharpoons\text{HCO}_3^-(aq)+\text{H}_3\text{O}^+(aq)[/tex]
Here, [tex]K_a_1[/tex] is the first dissociation constant of [tex]{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex].
Step 2: In the second dissociation, [tex]{\text{HCO}}_3^ -[/tex] dissociates as follows:
[tex]\text{H}_2\text{CO}_3^-(aq)+\text{H}_2\text{O}(aq)\overset{\text{K}_{al}}\leftrightharpoons\text{CO}_3^2\;(aq)+\text{H}_3\text{O}^+(aq)[/tex]
Here, [tex]{K_{{\text{a2}}}}[/tex] is the first dissociation constant of [tex]{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}[/tex].
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Answer details:
Grade: High School
Chapter: Acid, base and salts.
Subject: Chemistry
Keywords: acids, monoprotic, polyprotic, HCl, H2CO3, H2SO4, HNO3, CH3COOH, dissociation, Ka1, Ka2.
) Calculate the molarity of a solution prepared by dissolving 117 g of sodium chloride (NaCl) in enough water to make 2.7 liters of solution.
A leaf falls into a shallow lake and is rapidly buried in the sediment the sediment change choose to rock over millions of years which type of fossil would most likely be form
Titanium is a metal used to make golf clubs. a rectangular bar of this metal measuring 1.77 cm x 2.08 cm x 2.64 cm was found to have a mass of 48.9 g. what is the density of titanium in g/cm3? answer
A 25.0 ml sample of an unknown monoprotic acid was titrated with 0.12 m naoh. the student added 31.6 ml of naoh and went past the equivalence point. which procedure could be performed next to more accurately determine the concentration of the unknown acid?
How do sodium and potassium ions transfer in and out of an axon?
A.Through “gates” that open up
B.Through an absorption process
C.Through neural communication
D.Through an electrical process
Answer:
Option A= through gates that,s open up
Explanation:
The sodium and potassium ions transfer in and out the axon through electrical process. This process is called depolarization and re-polarization.
Depolarization:
Depolarization is occur when stimulus is given to the resting neuron. In this process gates of sodium ions on the membrane become open and sodium ions that are present out side. inter into the cell. because of this process the charge of the nerve changes (-70 mv to -55 mV).
Re-polarization:
when the re-polarization occur, potassium gates are open and the potassium ions goes outside the membrane. During this process electrical potential becomes negative inside the cell until the potential of -70 mV is re-attain i.e, resting potential.
In short we can say that depolarization allow sodium ions to inter into the nerve membrane and re-polarization allow potassium ions to moves out side the membrane.
Answer:
A.) Through gates that open up
Explanation:
Odyssey ware
Identify the oxidizing agent in the reaction: sn(s) + 2h+(aq) → sn2+(aq) + h2(g)
Explanation:
An oxidizing agent is defined as a substance which readily accepts an electron and itself gets reduced in order to oxidize another substance in a chemical reaction.
For example, [tex]2H^{+} + 2e^{-} \rightarrow H_{2}[/tex]
Here, hydrogen is getting reduced as its oxidation state is changing from +1 to 0 and hence it acts like an oxidizing agent.
In an oxidizing agent, a decrease in oxidation state occurs.
Whereas in [tex]Sn \rightarrow Sn^{2+} + 2e^{-}[/tex], tin is getting oxidized by gaining electrons. Therefore, it is acting as a reducing agent. An increase in oxidation state occurs for a reducing agent.
Thus, we can conclude that in the given reaction hydrogen is the oxidizing agent.
A solution with a ph of 4 has _________ the concentration of h+ present compared to a solution with a ph of 5.
How many moles are in 226 g of Fe(NO2)2 ?
The chemical formula for table sugar is C12H11O22. What can you tell from this formula?
There are 22 protons in an oxygen atom.
There are 12 electrons in a carbon atom.
The ratio of oxygen atoms to hydrogen atoms in a molecule of sugar is 2 to 1.
The ratio of carbon atoms to hydrogen atoms in a molecule of sugar is 2 to 1.
Answer: The correct answer is the ratio of oxygen atoms to hydrogen atoms in a molecule of sugar is 2 to 1.
Explanation:
The given chemical formula for table sugar is [tex]C_{12}H_{11}O_{22}[/tex].
The above compound contains 12 atoms of carbon atom, 11 atoms of hydrogen and 22 atoms of oxygen.
The ratio of oxygen atoms to hydrogen atoms is [tex]22:11::2:1[/tex] and the ratio of carbon atoms to hydrogen atoms in a molecule of sugar is [tex]12:11[/tex]
An oxygen atom contains 8 protons and a carbon atoms has 6 electrons.
Hence, the correct statement is the ratio of oxygen atoms to hydrogen atoms in a molecule of sugar is 2 to 1.
What is the empirical formula of a molecule containing 18.7% lithium, 16.3% carbon, and 65% oxygen?
What are ionic compounds typically composed of ?
A. A metal anion and a nonmetal cation
B. Two metal anions
C. A metal cation and non metal anion
D.Two nonmetal cations
Ionic compounds are generally formed from a metal cation (positively charged ion) and a nonmetal anion (negatively charged ion), so the correct answer to your question is option C.
Explanation:Ionic compounds are typically composed of a metal cation and nonmetal anion. This means the correct answer to your question is option C. A cation is a positively charged ion, and in this context, it is typically formed by an element from the left side of the periodic table, or a metal. An anion, on the other hand, is a negatively charged ion, usually formed by an element from the right side of the periodic table, or a nonmetal. When these ions combine, they create an ionic compound, such as NaCl (sodium chloride), where sodium is the metal cation and chloride is the nonmetal anion.
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Xas shown in table 15.2, kp for the equilibrium n21g2 + 3 h21g2 δ 2 nh31g2 is 4.51 * 10-5 at 450 °c. for each of the mixtures listed here, indicate whether the mixture is at equilibrium at 450 °c. if it is not at equilibrium, indicate the direction (toward product or toward reactants) in which the mixture must shift to achieve equilibrium. (a) 98 atm nh3, 45 atm n2, 55 atm h2 (b) 57 atm nh3, 143 atm n2, no h2 (c) 13 atm nh3, 27 atm n2, 82 atm h
A chemist mixes oxygen gas and hydrogen gas to form water, which is composed of one oxygen and two hydrogen atoms per molecule. What has occurred? A physical change B chemical change C combustion D precipitation
Answer: The formation of water is a chemical change.
Explanation:
Physical change is defined as the change in which change in shape and size takes place. The chemical composition of a substance remains the same. No new substance is formed during this.
For Example: Melting of ice
Chemical change is defined as the change in which change in chemical composition takes place. A new substance is formed in this.
For Example: Formation of water molecule.
The chemical equation for the formation of water molecule follows:
[tex]2H_2+O_2\righatarrow 2H_2O[/tex]
Hence, the formation of water is a chemical change.
If 4.8 moles of X and 3.4 moles of Y react according to the reaction below, how many moles of the excess reactant will be left over at the end of the reaction?
3X + 2Y “yields”/ X3Y2
1.7 mol Y left over
1.6 mol X left over
0.2 mol Y left over
0.1 mol X left over
Answer : The correct option is, 0.2 mole Y left over .
Explanation : Given,
Moles of X = 4.8 mole
Moles of Y = 3.4 mole
The balanced chemical reaction is,
[tex]3X+2Y\rightarrow X_3Y_2[/tex]
From the balanced reaction, we conclude that
As, 3 moles of X react with 2 moles of Y
So, 4.8 moles of X react with [tex]\frac{2}{3}\times 4.8=3.2[/tex] moles of Y
From this we conclude that, the reactant Y is an excess reagent and X is a limiting reagent.
The moles of excess reagent left over at the end of the reaction = Given moles of X - Required moles of X
The moles of excess reagent left over at the end of the reaction = 3.4 - 3.2 = 0.2 mole
Therefore, the moles of excess reagent left over at the end of the reaction is, 0.2 mole Y left over.
Answer:
The correct answer is : '0.2 mol Y left over'.
Explanation:
[tex]3X + 2Y \rightarrow X_3Y_2[/tex]
Moles of X = 4.8 moles
Moles of Y = 3.4 moles
According to reaction, 3 moles of X react with 2 moles of Y .
Then 4.8 moles of X react with :
[tex]\frac{2}{3}\times 4.8=3.2 [/tex]moles of Y
Moles of Y reacted = 3.2 moles
Moles of Y left unreacted = 3.4 moles - 3.2 moles = 0.2 moles
As we can see that X is in limiting amount and y is present in an excessive amount.And the left over amount of Y is 0.2 moles.
A substance was analyzed in a laboratory. It was composed of three elements in a fixed ratio. The substance is an ?
Explanation:
A compound is defined as the substance which contains different type of elements that chemically combine together in a fixed ratio by mass.
For example, [tex]CaCl_{2}[/tex] is a compound as it contains calcium and chlorine which are different elements. And, both Ca and Cl are combining in 1:2 ratio.
And, for every molecule of calcium chloride these elements will always be present in 1:2 ratio.
Thus, we can conclude that when a substance was analyzed in a laboratory. It was composed of three elements in a fixed ratio. The substance is a compound.
The base-dissociation constant of ethylamine (c2h5nh2) is 6.4 ??? 10???4 at 25.0 ??
c. the [h ] in a 1.2 ??? 10-2 m solution of ethylamine is ________ m.
[H⁺]=3.608.10⁻¹²
Further explanationWeak acid ionization reaction occurs partially (not ionizing perfectly as in strong acids)
The ionization reaction of a weak acid is an equilibrium reaction
HA (aq) ---> H⁺ (aq) + A⁻ (aq)
The equilibrium constant for acid ionization is called the acid ionization constant, which is symbolized by Ka
The values for the weak acid reactions above:
[tex]\rm Ka=\dfrac{[H][A^-]}{[HA]}[/tex]
The greater the Ka, the stronger the acid, which means the reaction to the right is also greater
Where Kb is the base ionization constant
LOH (aq) ---> L⁺ (aq) + OH⁻ (aq)
[tex]\rm Kb=\dfrac{[L][OH^-]}{[LOH]}[/tex]
Kb of Ethylamine (C₂H₅NH₂) : 6.4.10⁻⁴
The ethylamine ionization reactions occur in water as follows:
C₂H₅NH₂ + H₂O ⇒ C₂H₅NH₃⁺ + OH⁻
with a Kb value:
[tex]\rm Kb=\dfrac{[C_2H_5NH_3^+][OH^-]}{[C_2H_5NH_2]}[/tex]
for example x = number of moles / concentration that reacts
Initial concentration of Ethylamine (C₂H₅NH₂) : 1.2.10⁻²
Concentration at equilibrium = 1.2.10⁻² -x
Initial concentration of C₂H₅NH₃ = 0
Concentration at equilibrium = x
Initial concentration OH⁻ = 0
Concentration at equilibrium = x
so the value of Kb =
[tex]\rm Kb=\dfrac{[x][x]}{[1.2.10^{-2}-x]}\\\\assumption\:x=so\:small\:then\\\\6.4.10^{-4}=\dfrac{x^2}{1.2.10^{-2}}\\\\x^2=7.68.10^{-6}\\\\x=2.771.10^{-3}[/tex]
x = [OH⁻] = 2.771.10⁻³
Ka x Kb = [H⁺] [OH-]
a water equilibrium constant value (Kw) of 1.10⁻¹⁴ at 25 °C
Ka x Kb = [H +] [OH-] = 1.10⁻¹⁴
1.10⁻¹⁴ = [H⁺] . 2.771.10⁻³
[H⁺]=3.608.10⁻¹²
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For each bond, show the direction of polarity by selecting the correct partial charges. si-p si-s s-p the most polar bond is
The biggest elctronegative difference is between silicon and sulfur. So Si-S will be most polar bond.
The polarity between the two atoms is determined by their relative difference in electronegativity.
The Electronegativity of ,
Silicon= 1.9
Phosphorus= 2.19
Sulfur= 2.58
The direction of polarity,
[tex]\rm \bold{ \delta^+Si\rightarrow \delta^-P}\\\rm \bold{ \delta^+Si\rightarrow \delta^-S}\\\rm \bold{ \delta^+P\rightarrow \delta^-S}[/tex]
Since, the biggest elctronegative difference is between silicon and sulfur (Si-S).
Hence we can say that Si-S will be most polar bond.
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Q 9.3: how many triplets would you expect to observe in the 1h nmr spectra for o-chlorotoluene
Answer:
No triplet.
Explanation:
A triplet is observed in proton nmr when the neighboring, chemically non equivalent, carbon atoms bear two hydrogen atoms.
Let us examine the structure of o-chlorotoluene [shown in figure].
As shown in the figure there is no carbon bearing two equivalent hydrogen.
There are five non equivalent kind of hydrogen on the molecule
Three hydrogen are equivalent (Ha)
So we will observe only
a) Singlet
b) Doublet
c) Double doublet (split doublet)
Which acid is the best choice to create a buffer with ph= 3.19?
-As the temperature increased, what happened to the N2O4 concentration?
PLEASE HELP! Which clade is composed of eukaryotes which are multicellular and heterotrophs? A) Eubacteria B) Fungi C) Plant D) Animals
Answer: D) Animals
Explanation:
Eukaryotic organisms are those organisms which exhibit complex cellular composition. They exhibit membrane bound organelles and nucleus is also enclosed inside a membrane which encloses the genetic material of the organisms. Examples include plants, animals and fungi.
Multicellular organisms are those which exhibit multiple layers of the cells to perform a specialized function.
Hetrotrophic organisms are those which are dependent upon other organisms for their food and nourishment.
Among the given options, Animals is the correct option. This is due to the fact that all animals are eukaryotic organisms as they have a membrane bound nucleus and other cellular organelles. All animals are multicellular because of the fact that multicellular system is necessary for performing specialized functions required for survival. They are incapable of synthesizing their own food either by chemosythesis or photosynthesis. They are dependent upon other organisms like plants and other animals for their food.