Answer:
molar heat of combustion = -5156 *10³ kJ/mol
Explanation:
A quantity of 1.435 g of naphthalene , was burned in a constant-volume bomb calorimeter. Consequently, the temperature of the water rose from 20.28oC to 25.95oC If the heat capacity of the bomb plus water was 10.17 kJ/°C, calculate the heat of combustion of naphthalene on a molar basis; that is, find the molar heat of combustion.
Step 1: Data given
Mass of naphthalene = 1.435 grams
Initial temperature of water = 20.28 °C
Final temperature of water = 25.95 °C
heat capacity of the bomb plus water was 10.17 kJ/°C
Molar mass naphtalene = 128.2 g/mol
Step 2:
Qcal = Ccal * ΔT
⇒with Qcal =the heat of combustion
⇒with Ccal = heat capacity of the bomb plus water = 10.17 kJ/°C
⇒with ΔT = the difference in temperature = T2 - T1 = 25.95 - 20.28 = 5.67°C
Qcal = 10.17 kJ/°C * 5.67 °C
Qcal = 57.7 kJ
Step 3: Calculate moles
Moles naphthalene = 1.435 grams / 128.2 g/mol
Moles naphthalene = 0.01119 moles
Step 4: Calculate the molar heat of combustion
molar heat of combustion = Qcal/ moles
molar heat of combustion = -57.7 kJ/ 0.01119 moles
molar heat of combustion = -5156 *10³ kJ/mol
What is the gravitational potential energy of a 1500-kg truck resting on top of a 550-m hill on earth?( earth’s gravitational pull is 9.8m/s2).
Answer:
E = 8085 kJ
Explanation:
Given that,
The mass of a truck, m = 1500 kg
Height, h = 550 m
We need to find the gravitational potential energy of the truck. It can be calculated as follows :
[tex]E=mgh[/tex]
Put all the values,
[tex]E=1500\times 9.8\times 550\\\\E=8085000\ J\\\\or\\\\E=8085\ kJ[/tex]
So, the gravitational potential energy is 8085 kJ.
Which one of the following molecule is planer?
a. NF3 c. PH3
b. BH3 d. NCl3
Answer:
option a
hope helps you
have a great day
Which equation obeys the law of conservation of
mass?
Answer:2C4H10+2C12+12O2 4CO2+CC14+H20
What is unit? Write down the units of mass, temperature and power
Explanation:
a single thing, person, or group forming part of a whole There are 36 units in my apartment building. the least whole number : one. a fixed quantity (as of length, time, or value) used as a standard of measurement An inch is a unit of length.mass=kilogram (kg)
temperature=kelvin
power=watt
hope it helps
stay safe healthy and happy..By how many times would you expect Al2(SO4)3 to depress the F.P of water compared to sucrose C12H22011 ?
Answer:
By how many times would you expect Al2(SO4)3 to depress the F.P of water compared to sucrose C12H22011 ?.
Explanation:
The freezing point of a pure solvent decreases further by adding a nonvolatile solute.
This is called depression in freezing point.
When an ionic solute is dissolved then the depression in the freezing point is proportional to the number of ions present in the solution.
In aluminum sulfate, there are five ions formed as shown below:
[tex]Al_2(SO_4)_3(aq)->2Al^3^+(aq)+3SO_4^2^-(aq)[/tex]
But sucrose is a covalent compound and it does not undergo dissociation.
Hence, aluminum sulfate decreases the freezing point of water by five times compared to sucrose.
Explanation:
what is the machine used to check melting point called?
Answer:
Melting-point apparatus
Which of the five type of equilibrium problems best applies to this question: Consider the following reaction at equilibrium. What effect will reducing the volume of the reaction mixture have on the system
Answer:
d
Explanation:
Predict the product when 2-methylbutanol is oxidised with pyridium chlorochromate in dichloromethane (PCC/CH2C12) a. CH3CH2CH(CH3)COOH b. CH3CH2CH2CH(CH3)CHO C. CH3CH2CH(CH3)CHO d. CH3CH2CH(CH3)OH 8:40 PM Type a message
Answer:
c. CH3CH2CH(CH3)CHO
Explanation:
Hello there!
In this case, according to the process for the one-step oxidation of a primary alcohol with a moderately strong oxidizing agent like pyridinium chlorochromate (PCC), whereby an aldehyde is produced, we infer that the corresponding product will be 2-methylbutanal, which matches with the choice c. CH3CH2CH(CH3)CHO according to the following reaction:
[tex]CH_3CH_2CH(CH_3)CH_2OH\rightarrow CH_3CH_2CH(CH_3)COH[/tex]
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Which statement describes an electron?
EEEE
It has a positive charge and is located in the nucleus.
O It has a positive charge and is located in orbitals around the nucleus.
It has a negative charge and is located in the nucleus.
O It has a negative charge and is located in orbitals around the nucleus.
Answer:
It has a negative charge and is located in orbitals around the nucleus
Explanation:
The statement describes an electron is " It has a negative charge and is located in orbitals around the nucleus."
What is electron?The electron would be a subatomic particle with a negatively one elementary charge electric charge.
What is nucleus?Protons, that have a positive charge, as well as neutrons, which have no electrical charge, make up the nucleus. Quarks were subatomic particles that make up protons but also neutrons.
Electrons were present surrounding the atom's nucleus, in contrast to protons as well as neutrons, that are contained within the nucleus at its core. Negative electrons were drawn to the positive nucleus since the electric charges of opposite polarity attract one another.
To know more about electrons and nucleus.
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Di- n- pentyl ether can be converted to 1- bromopentane by treatment with HBr through essentially a(n) ________ mechanism.
Answer:
SN1 mechanism
Explanation:
The mechanism of this reaction is shown in the image attached.
The Di- n- pentyl ether is first protonated. The CH3(CH2)4OH is now a good leaving group as shown.
The attack of the bromide ion on the cation formed completes the mechanism to yield 1- bromopentane as shown in the mechanism.
Que es la actividad física y en qué mejora
How do forces between particles in gases compare to forces in the other states of matter?
The forces in gases are weaker than forces in solids and liquids.
Because they have more kinetic energy that overcomes the force of attraction.
I mix together 50.0 mL of 0.100 M NaIO3, 50.00 mL of 0.100 M NaOH, and 10.0 mL of 0.100 M HIO3. What is the pH of the mixture
Answer:
pH = 12.66
Explanation:
The HIO3 reacts with NaOH as follows:
HIO3 + NaOH → H2O + NaIO3
The moles of HIO3 and NaOH added are:
Moles HIO3:
0.0100L * (0.100mol / L) = 0.00100 moles HIO3
Moles NaOH:
0.05000L * (0.100mol / L) = 0.00500 moles NaOH
As moles NaOH > Moles HIO3, the moles of NaOH that remain are:
0.00500mol - 0.00100mol = 0.00400 moles NaOH.
After the reaction you will have only NaOH and NaIO3. As NaIO3 is a salt, the pH of the solution is determined by only NaOH. Its concentration is:
Moles NaOH: 0.00500 moles NaOH
Volume: 50.0mL + 50.0mL + 10.0mL = 110.0mL = 0.110L
Molarity: 0.0455M NaOH = [OH-]
pOH = -log [OH-] = 1.34
pH = 14 - pOH
pH = 12.66pH is the measure of the hydrogen or the hydronium ion in an aqueous solution. The pH of the mixture containing sodium hydroxide is 12.66.
What is pH?pH is the potential of the hydrogen and is given as a negative log of the hydrogen concentration in the aqueous solution.
The balanced chemical reaction can be shown as:
[tex]\rm HIO_{3} + NaOH \rightarrow H_{2}O + NaIO_{3}[/tex]
Moles of iodic acid are calculated as:
[tex]\begin{aligned} \rm moles &= \rm molarity \times volume\\\\&= 0.100 \;\rm M \times 0.0100 \;\rm L \\\\&= 0.00100\;\rm moles\end{aligned}[/tex]
Moles of sodium hydroxide are calculated as:
[tex]\begin{aligned} \rm moles &= \rm molarity \times volume\\\\&= 0.100 \;\rm M \times 0.05000 \;\rm L \\\\&= 0.00500\;\rm moles\end{aligned}[/tex]
The remaining moles of sodium hydroxide are 0.00500mol - 0.00100mol = 0.00400 moles.
The pH of the mixture will be determined by sodium hydroxide, as sodium iodate is a salt.
The molar concentration of sodium hydroxide is calculated as:
[tex]\begin{aligned} \rm M &= \rm \dfrac{moles}{volume}\\\\&= \dfrac{0.00500}{0.110}\\\\&= 0.0455 \;\rm M\end{aligned}[/tex]
pH is calculated as:
[tex]\begin{aligned} \rm pOH &= \rm -log[OH^{-}] = 1.34\\\\\rm pH &= \rm 14 - pOH\\\\\rm pH &= 12.66\end{aligned}[/tex]
Therefore, 12.66 is the pH of the mixture.
Learn more about pH here:
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A 250 mL sample of gas at 1.00 atm and has the temperature increased to and the volume increased to 500 mL. What is the new pressure
Answer:
0.53atm = P2
Explanation:
Gas at 1.00atm and 20°C. Temperature increased to 40°C...
We can solve this question using combined gas law:
P1*V1 / T1 = P2*V2 / T2
Where P is pressure, V volume and T absolute temperature of 1, initial state and 2, final state.
Compunting the values of the problem:
P1 = 1.00atm
V1 = 250mL
T1 = 20°C + 273.15 = 293.15K
P2 = ?
V2 = 500mL
T2 = 40°C + 273.15 = 313.15K
1.00atm*250mL / 293.15K = P2*500mL / 313.15K
0.53atm = P2
I need help with the practice question at the bottom. Thank you.
Explanation:
For this question, we apply the equation: Q = mCp AT Where m is the mass of the substance, Cp
is its specific heat capacity and AT is the
temperature change. Q = 896 x 0.45 x (5-94)
Q = -35884.8 Joules
So about -36 kilojoules of heat is released.
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the force of attraction between non polar molecules are what (a)electrovalent bond (b)covalent bond (c)Hydrogen bond (d)Van der waals forces
Answer:
d. van der waals force
Explanation:
Van der Waals force :
the weakest intermolecular forceand consist of dipole-dipole force and dispersion force.
If 0.250 L of a 5.90 M HNO₃ solution is diluted to 2.00 L, what is the molarity of the new solution?
Answer:
0.74 M
Explanation:
From the question given above, the following data were obtained:
Molarity of stock solution (M₁) = 5.90 M
Volume of stock solution (V₁) = 0.250 L
Volume of diluted solution (V₂) = 2 L
Molarity of diluted solution (M₂) =?
The molarity of the diluted solution can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂
5.90 × 0.250 = M₂ × 2
1.475 = M₂ × 2
Divide both side by 2
M₂ = 1.475 / 2
M₂ = 0.74 M
Thus, the molarity of the diluted solution is 0.74 M
A major component of gasoline is octane when octane is burned in air it chemically reacts with oxygen to produce carbon dioxide and water what mass of carbon dioxide is produced by the reaction of oxygen
gasoline is the chemical that is coming out of the air
A beaker is filled to the 500 mL mark with alcohol. What increase in volume (in mL) does the beaker contain when the temperature changes from 5° C to 30° C? (Neglect the expansion of the beaker, evaporation of alcohol and absorption of water vapor by alcohol.) The volume coefficient of expansion γγ for alcohol = 1.12 x 10-4 K-1
Answer:
"1.4 mL" is the appropriate solution.
Explanation:
According to the question,
[tex]v_0=500[/tex][tex]\alpha =1.12\times 10^{-4}[/tex][tex]\Delta \epsilon = 25[/tex]Now,
Increase in volume will be:
⇒ [tex]\Delta V = \alpha\times v_0\times \Delta \epsilon[/tex]
By putting the given values, we get
[tex]=1.12\times 10^{-4}\times 500\times 25[/tex]
[tex]=1.12\times 10^{-4}\times 12500[/tex]
[tex]=1.4 \ mL[/tex]
If a hydrogen atom and a helium atom have the same kinetic energy:________
a. the wavelength of the hydrogen atom will be about 4 times longer than the wavelength of the helium atom.
b. the wavelength of the hydrogen atom will be about 2 times longer than the wavelength of the helium.
c. the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
d. the wavelength of the helium atom will be about 2 times longer than the wavelength of the hydrogen atom.
e. the wavelength of the helium atom will be about 4 times longer than the wavelength of the hydrogen atom.
Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
Explanation:
The relation between energy and wavelength is as follows.
[tex]E = \frac{hc}{\lambda}\\[/tex]
This means that energy is inversely proportional to wavelength.
As it is given that energy of a hydrogen atom and a helium atom is same.
Let us assume that [tex]E_{hydrogen} = E_{helium} = E'[/tex]. Hence, relation between their wavelengths will be calculated as follows.
[tex]E_{hydrogen} = \frac{hc}{\lambda_{hydrogen}}[/tex] ... (1)
[tex]E_{helium} = \frac{hc}{\lambda_{helium}}[/tex] ... (2)
Equating the equations (1) and (2) as follows.
[tex]E_{hydrogen} = E_{helium} = E'\\\frac{hc}{\lambda_{hydrogen}} = \frac{hc}{\lambda_{helium}} = E'\\\lambda_{helium} = \lambda_{hydrogen} = E'[/tex]
Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
I need help with the practice question at the bottom. Thank you.
As the gas expands on the surrounding, work is done by the system.
Therefore, W= -279J
Absorbtion of heat,q= +216J
∆U=q+W = (216-279)J= -63J
En la fermentación del alcohol, la levadura convierte la glucosa en etanol y dióxido de carbono:
C6H12O6(s) → 2C2H5OH(l) + 2CO2(g)
Si reaccionan 5.97 g de glucosa y se recolectan 1.44 L de CO2 gaseoso, a 293 K y 0.984 atm, ¿cuál
es el rendimiento porcentual de la reacción
Answer:
88.9%
Explanation:
Primero convertimos 5.97 g de glucosa a moles, usando su masa molar:
5.97 g ÷ 180 g/mol = 0.0332 molDespués calculamos la cantidad máxima de moles de CO₂ que se hubieran podido producir:
0.0332 mol C₆H₁₂O₆ * [tex]\frac{2molCO_2}{1molC_6H_{12}O_6}[/tex] = 0.0664 mol CO₂Ahora calculamos los moles de CO₂ producidos, usando los datos de recolección dados y la ecuación PV=nRT:
0.984 atm * 1.44 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 293 Kn = 0.0590 molFinalmente calculamos el rendimiento porcentual:
0.0590 mol / 0.0664 mol * 100% = 88.9%An unknown compound's 2,4-DNP product melting range is between 144-146'C. It does not give a silver mirror on the Tollens test and is slow to react to the chromic acid test. What would this compound be
Answer:
An unknown compound's 2,4-DNP product melting range is between 144-146'C. It does not give a silver mirror on the Tollens test and is slow to react to the chromic acid test. What would this compound be
Explanation:
From the given data it is clear that the unknown compound gives positive test with 2,4-DNP reagent.
That means it has a carbonyl group.Either aldehyde or ketone.
It does not give a silver mirror on the Tollens test and is slow to react to the chromic acid test.
That means aldehyde is absent.
So, the other carbonyl group that is ketone is present in the given unknown compound.
Pls pls help me me pls
Answer:
Danger
Explanation:
Draw structures corresponding to the following IUPAC names:(a) (Z)-2-Ethyl-2-buten-1-ol (b) 3-Cyclohexen-1-ol(c) trans-3-Chlorocycloheptanol (d) 1,4-Pentanediol(e) 2,6-Dimethylphenol (f ) o-(2-Hydroxyethyl)phenol
Answer:
Draw structures corresponding to the following IUPAC names:(a) (Z)-2-Ethyl-2-buten-1-ol (b) 3-Cyclohexen-1-ol(c) trans-3-Chlorocycloheptanol (d) 1,4-Pentanediol(e) 2,6-Dimethylphenol (f ) o-(2-Hydroxyethyl)phenol
Explanation:
According to IUPAC rules, the name of a compound is:
Prefix+root word+suffix
1) Select the longest carbon chain and it gives the root word.
2) The substituents give the prefix.
3) The functional group gives the secondary suffix and the type of carbon chain gives the primary suffix.
The structure of the given compounds are shown below:
What are the uses of Sulphuric acid?
Answer:
The major use of sulfuric acid is in the production of fertilizers, e.g., superphosphate of lime and ammonium sulfate. It is widely used in the manufacture of chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, and drugs.
The major use of sulfuric acid is in the production of fertilizers, e.g., superphosphate of lime and ammonium sulfate. It is widely used in the manufacture of chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, and drugs.
Rank each of the following gases in order of increasing urms assuming equivalent amounts and all gases are at the same temperature and pressure where 1 has the lowest urms and 4 has the highest urms.
a. Gas 1 : H2S
b. Gas: He
c. Gas 3: NF3
d. Gas 4: H2O
The Urms refers to the root mean square speed of the gas. The order of increasing Urms for the gases shown in the question; NF3 < H2S < H2O < He.
What is the Urms?The Urms refers to the root mean square speed of the gas. This is ultimately dependent on the relative molecular mass of the gases when they are maintained at the same temperature.
Now, let us look at the order of increasing Urms for the gases shown in the question; NF3 < H2S < H2O < He.
Learnmore about Urms: https://brainly.com/question/365923
A sample of Br2(g) takes 12.0 min to effuse through a membrane. How long would it take the same number of moles of Ar(g) to effuse through the same membrane
Answer:
6 mins
Explanation:
The time taken for Ar to effuse can be obtained as follow:
Time for Br₂ (t₁) = 12 mins
Molar mass of Br₂ (M₁) = 2 × 80 = 160 g/mol
Molar mass of Ar (M₂) = 40 g/mol
Time for Ar (t₂) =?
t₂/t₁= √(M₂/M₁)
t₂ / 12 = √(40/160)
Cross multiply
t₂ = 12 × √(40/160)
t₂ = 12 × 0.5
t₂ = 6 mins
Therefore, it will take 6 mins for the same amount of Ar to effused out.
An unknown weak acid with a concentration of 0.530 M has a pH of 5.600. What is the Ka of the weak acid
Answer:
Ka = 3.45x10⁻⁶
Explanation:
First we calculate [H⁺], using the given pH:
pH = -log[H⁺][H⁺] = [tex]10^{-pH}=10^{-5.6}[/tex] [H⁺] = 2.51x10⁻⁶ MTo solve this problem we can use the following formula describing a monoprotic weak acid:
[H⁺] = [tex]\sqrt{C*Ka}[/tex]We input the data that we already know:
2.51x10⁻⁶ = [tex]\sqrt{0.530*Ka}[/tex]And solve for Ka:
Ka = 3.45x10⁻⁶Cal is titrating 57.7 mL of 0.311 M HBr with 0.304 M Ba(OH)2. How many mL of Ba(OH)2 does Cal need to add to reach the equivalence point?
Answer:
118.06 mL
Explanation:
The neutralization reaction between HBr (acid) and Ba(OH)₂ (base) is the following:
2HBr + Ba(OH)₂ → BaBr₂ + 2H₂O
According to the equation, 2 moles of HBr react with 1 mol Ba(OH)₂. Thus, at the equivalence point the moles of acid and base react completely:
2 moles HBr = 1 mol Ba(OH)₂
We can replace the moles by the product of the molar concentration (M) and volume (V):
2 x (M HBr) x (V HBr) = M Ba(OH)₂ x V Ba(OH)₂
Now, we introduce the data in the equation to calculate the volume in mL of Ba(OH)₂:
V Ba(OH)₂ = (2 x (M HBr) x (V HBr))/M Ba(OH)₂
= (2 x 0.311 M x 57.7 mL)/(0.304 M)
= 118.06 mL
Therefore, 118 mL of Ba(OH)₂ are needed.
