Answer:
0.804g of NaHCO₃ you must add
Explanation:
pKa of HCO₃⁻/CO₃²⁻ is 10.32.
It is possible to find pH of a buffer by using H-H equation, thus:
pH = pka + log [A⁻] / [HA]
Where [HA] is concentration of acid (HCO₃⁻) and [A⁻] is concentration of conjugate acid (CO₃²⁻).
Moles of CO₃²⁻ = K₂CO₃ are:
4.00g ₓ (1mol / 138.206g) = 0.0289 moles CO₃²⁻
Replacing:
10.80 = 10.32 + log [0.0289] / [HCO₃⁻]
[HCO₃⁻] = 0.009570 moles you need to add to obtain the desire pH
As molar mass of NaHCO₃ is 84.007g/mol, mass of NaHCO₃ is:
0.009570 moles ₓ (84.007g / mol) =
0.804g of NaHCO₃ you must addAnswer:
[tex]0.8237g[/tex] of [tex]NaHCO_3[/tex] must be addedExplanation:
Second dissociation of [tex]H_2CO_3[/tex] is
[tex]HCO_3^-(aq) <-------> CO_3^2-(aq) + H^+[/tex]
[tex]Ka = [CO_3^{2-}] [H+] / [HCO_3^-] \\\\= 4.7*10^{-11}\\\\pKa = -log(4.7 * 10^{-11}) \\\\= 10.33[/tex]
[tex]pH = pKa + \frac{log([A-]}{[HA])}\\\\required pH = 10.80\\\\10.80 = 10.33 + \frac{log([A-]}{[HA])}\\\\\frac{log([A-]}{[HA])} \\\\= 0.47\\\\\frac{[A-]}{[HA]}\\\\ = 2.951[/tex]
[tex][CO_3^{2-}] / [HCO_3^-] = 2.951[/tex]
[tex][HCO_3^-] = [CO_3^{2-}]/2.951[/tex]
moles of [tex]K_2CO_3[/tex] = [tex]\frac{4}{138.206} = 0.028942mol[/tex]
moles of [tex]CO_3^{2-}[/tex] = [tex]0.028942mol[/tex]
[tex][CO_3^{2-}][/tex] = [tex]\frac{0.028942}{500} * 1000 = 0.05788M[/tex]
[tex][HCO_3^-][/tex] required = [tex]\frac{[CO32-]}{2.951} = \frac{0.05788}{2.951} = 0.01961M[/tex]
moles of [tex]HCO_3^-[/tex] required = [tex]\frac{0.01961}{1000} * 500 = 0.009805mol[/tex]
moles [tex]NaHCO_3[/tex] required = [tex]0.009805mol[/tex]
Therefore,
mass of [tex]NaHCO_3[/tex] required [tex]= 0.009805 * 84.007 = 0.8237g[/tex]
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Which of the following would describe a spontaneous process? (Select all that apply.) ΔGreaction < 0 ΔSuniverse < 0 ΔSuniverse > 0 ΔHreaction > 0 ΔHreaction < 0 ΔGreaction > 0
Answer:
ΔGreaction < 0
ΔSuniverse > 0
ΔHreaction < 0
Explanation:
A spontaneous process is one which can proceed without additional input of energy releasing free energy in the process and then moves to a lower more stable thermodynamical state.
For an isolated system, a spontaneous process proceeds with an increase in entropy.
The conditions for a spontaneous process at constant temperature and pressure, can be determined using the change in Gibbs free energy, which is given by: ∆G = ∆H - T∆S
Where ∆G is change in free energy; ∆H is change in enthalpy or Heat content; ∆S is change in entropy, T is temperature.
For a process to be spontaneous, the following conditions are necessary:
1. ∆G < 0; must be negative
2. ∆S > 0; there must be an increase in entropy
3. ∆H < 0; enthalpy change must be negative such that heat is lost to the surroundings
The above conditions ensures that ∆G is negative and the process is spontaneous.
El ejemplo más claro para definir una cadena de electricidad es una red de pesca, si fuera posible identificar una sola partícula representativa de esta fuerza , ¿ Cuál partícula se identificaría? *
Bosón W
Fotón
Glúon
Leptón
Answer:
Leptón
Explanation:
Lepton son partículas elementales de espín de medio entero (espín 1⁄2), y se sabe que no experimentan interacciones fuertes. Los leptones se clasifican en leptones cargados (los leptones similares a los electrones) y leptones neutros (conocidos como neutrinos). Un electrón es un leptón. Los leptones cargados pueden combinarse con otras partículas para formar átomos compuestos de partículas y positronio, mientras que los neutrinos rara vez interactúan con algo, lo que los hace raros de observar.
Dado que la electricidad es el resultado del movimiento o flujo de electrones, la única partícula representativa de esta fuerza es el leptón.
At a particular temperature, an equilibrium mixture the reaction below was found to contain 0.171 atm of I2, 0.166 atm of Cl2 and 9.81 atm of ICl. Calculate the value of the equilibrium constant, Kp at this temperature.I2(g) + Cl2(g) <=> 2 ICl(g)
Answer: 3390
Explanation:
Since this problem already gives is the equilibrium values, all we have to do is to plug them into the formula for [tex]K_{p}[/tex].
[tex]K_{p} =\frac{[ICl]^2}{[I_{2}][Cl_{2}] }[/tex]
[tex]K_{p} =\frac{(9.81)^2}{(0.171)(0.166)} =3390[/tex]
What is Key for the reaction 2503(9) = 2802(9) + O2(g)?
Answer:
Option C. Keq = [SO2]² [O2] /[SO3]²
Explanation:
The equilibrium constant keq for a reaction is simply the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Now, let us determine the equilibrium constant for the reaction given in the question.
This is illustrated below:
2SO3(g) <==> 2SO2(g) + O2(g)
Reactant => SO3
Product => SO2, O2
Keq = concentration of products /concentration of reactants
Keq = [SO2]² [O2] /[SO3]²
Carbon dioxide and water vapor are variable gases because _____.
Answer: their amounts vary throughout the atmosphere
Explanation:
There is very little that travels over the atmosphere
Vary=very little
Hope that helps
what’s the SI unit of time ?
Answer:
The answer is A
Explanation:
The following reactions all have K < 1. 1) HCOO- (aq) + C6H5COOH (aq) HCOOH (aq) + C6H5COO- (aq) 2) C9H7O4- (aq) + C6H5COOH (aq) C6H5COO- (aq) + HC9H7O4 (aq) 3) HCOOH (aq) + C9H7O4- (aq) HC9H7O4 (aq) + HCOO- (aq) Arrange the substances based on their relative acid strength.
Answer:
Explanation:
C₉H₇O₄⁻ = weakest base
C₆H₅COO⁻ = strongest base
HCOO⁻ = intermediate base
HCOOH = not a Bronsted-Lowry base
HC₉H₇O₄ = not a Bronsted-Lowry base
C₆H₅COOH = not a Bronsted-Lowry base
The enthalpy change for the complete burning of one mole of a substance
is the enthalpy of _______
thermochemical equation
combustion
released
vaporization
fusion
absorbed
heat
Answer:
combustion
Explanation:
The enthalpy change for the complete burning of one mole of a substance
is the enthalpy of __combustion_____ .
Consider the reaction of aqueous potassium sulfate with aqueous g silver nitrate based on the solubility rule predict the product likely to be precipitate write a balanced molecular equation describing the reaction.
Answer:
K₂SO₄(aq) + 2AgNO₃ (aq) → 2KNO₃(aq) + Ag₂SO₄ (s) ↓
2Ag⁺ (aq) + SO₄⁻²(aq) ⇄ Ag₂SO₄ (s) ↓
Explanation:
Our reactants are: K₂SO₄ and AgNO₃
By the solubility rules, we know that sulfates are insoluble when they react to Ag⁺, Pb²⁺, Ca²⁺, Ba²⁺, Sr²⁺, Hg⁺
We also determine, that salts from nitrate are all soluble.
The reaction is:
K₂SO₄(aq) + 2AgNO₃ (aq) → 2KNO₃(aq) + Ag₂SO₄ (s) ↓
2Ag⁺ (aq) + SO₄⁻²(aq) ⇄ Ag₂SO₄ (s) ↓
A solution that is 0.135 M is diluted to make 500.0 mL of a 0.0851 M solution. How many milliliters of the original solution were required? View Available Hint(s) A solution that is 0.135 M is diluted to make 500.0 mL of a 0.0851 M solution. How many milliliters of the original solution were required? 5.74 mL 0.315 mL 793 mL 315 mL
Answer:
315mL
Explanation:
Data obtained from the question include the following:
Molarity of stock solution (M1) = 0.135 M
Volume of stock solution needed (V1) =?
Molarity of diluted solution (M2) = 0.0851 M
Volume of diluted solution (V2) = 500mL
The volume of the stock solution needed can be obtain as follow:
M1V1 = M2V2
0.135 x V1 = 0.0851 x 500
Divide both side by 0.135
V1 = (0.0851 x 500) / 0.135
V1 = 315mL
Therefore, the volume of the stock solution needed is 315mL
Suppose 1.87g of nickel(II) bromide is dissolved in 200.mL of a 52.0mM aqueous solution of potassium carbonate. Calculate the final molarity of nickel(II) cation in the solution. You can assume the volume of the solution doesn't change when the nickel(II) bromide is dissolved in it.
Answer:
Molarity = 0.0428 M = 42.8 mM
Explanation:
Step 1: Data given
Mass of nickel(II) bromide = 1.87 grams
Molar mass of nickel(II) bromide = 218.53 g/mol
Volume = 200 mL = 0.200 L
Step 2: Calculate moles of nickel(II) bromide
Moles nickel (II) bromide = mass / molar mass
Moles nickel (II) bromide = 1.87 grams / 218.53 g/mol
Moles nickel (II) bromide = 0.00856 moles
Step 3: Calculate moles nickel (II) cation
For 1 mol NiBr2 we have 1 mol Ni^2+
For 0.00856 moles NiBr2 we have 0.00856 moles Ni^2+
Step 4: Calculate final molarity of Ni^2+
Molarity = moles / volume
Molarity = 0.00856 moles / 0.200 L
Molarity = 0.0428 M = 42.8 mM
calculate how many moles of CaCl2•2H2O are present in 1.50 g of CaCl2•2H2O and then calculate how many moles of pure CaCl2 are present in the 1.50 g of CaCl2•2H2O.
Answer:
[tex]0.0102~mol~CaCl_2*2H_2O[/tex]
[tex]0.0102~mol~CaCl_2[/tex]
Explanation:
For this question, we have to start with the molar mass calculation of [tex]CaCl_2*2H_2O[/tex]. For this, we have to know the atomic mass of each atom:
O: 16 g/mol
Cl: 35.45 g/mol
H: 1 g/mol
Ca: 40 g/mol
If we take into account the amount of each atom in the formula we will have:
[tex](40*1)+(35.45*2)+(1*4)+(16*2)=~147.01~g/mol[/tex]
So, in 1 mol of [tex]CaCl_2*2H_2O[/tex] we will have 147.01 g. Now we can do the conversion:
[tex]1.50~g~CaCl_2*2H_2O\frac{1~mol~CaCl_2*2H_2O}{147.01~g~CaCl_2*2H_2O}=0.0102~mol~CaCl_2*2H_2O[/tex]
Additionally, in 1 mol of [tex]CaCl_2*2H_2O[/tex] we will have 1 mol of [tex]CaCl_2[/tex]. Therefore, we have a 1:1 mol ratio . With this in mind, we will have the same number of moles for [tex]CaCl_2[/tex]
[tex]0.0102~mol~CaCl_2*2H_2O=0.0102~mol~CaCl_2[/tex]
I hope it helps!
What is the Lewis structure for *OPCl3 and AlCl6^3-? What are their electron/molecular geometry and Ideal Bond Angle ?
Answer:
Here's what I get
Explanation:
1. POCl₃
(a) Lewis structure
Set P as the central atom, with O and Cl atoms directly attached to it.
Electrons available = P + O + 3Cl = 5 + 6 + 3×7 = 11 + 21 = 32
Arrange these electrons to give every atom an octet. Put a double bond between P and O.
You get the structure shown below.
(b) Geometry
There are four bond pairs and no lone pairs about the P atom.
Electron pair geometry — tetrahedral
Molecular geometry — tetrahedral
(c) Ideal bond angles
Tetrahedral bond angle = 109.5°
2. AlCl₆³⁻
(a) Lewis structure
Set Al as the central atom, with the Cl atoms directly attached to it.
Electrons available = Al + 6Cl + 3(-) = 3 + 6×6 +3 = 6 + 36 = 42
Arrange these electrons to give every atom an octet. Assign formal charges.
You get the structure shown below.
(b) Geometry
There are six bond pairs and no lone pairs about the Al.
Electron pair geometry — octahedral
Molecular geometry — octahedral
(c) Ideal bond angles
Axial-equatorial = 90°
Equatorial-equatorial = 120°
Axial-axial = 180°
Telluric acid (H2TeH4O6) is a diprotic acid with Ka1 = 2.0x10-8 and Ka2 = 1.0x10-11. A 0.25 M H2TeH4O6 contains enough HCl so that the pH is 3.00. What is the concentration of HTeH4O6
Answer:
5x10⁻⁶ = [HTeH₄O₆⁺]
Explanation:
The first dissociation equilibrium of the telluric acid in water is:
H₂TeH₄O₆ + H₂O ⇄ HTeH₄O₆⁺ + H₃O⁺
Using H-H equation for telluric acid:
pH = pKa + log₁₀ [HTeH₄O₆⁺] / [H₂TeH₄O₆]
pKa of telluric acid is -logKa1
pKa = -log 2.0x10⁻⁸
pKa = 7.699
As concentration of [H₂TeH₄O₆] is 0.25M, replacing in H-H equation:
3.00 = 7.699+ log₁₀ [HTeH₄O₆⁺] / [0.25M]
-4.699 = log₁₀ [HTeH₄O₆⁺] / [0.25M]
2x10⁻⁵ = [HTeH₄O₆⁺] / [0.25M]
5x10⁻⁶ = [HTeH₄O₆⁺]In electrophilic aromatic substitution reactions, a chlorine substituent is ________. In electrophilic aromatic substitution reactions, a chlorine substituent is ________. an activator and a meta-director a deactivator and an ortho,para-director an activator and an ortho,para-director a deactivator and a meta-director none of the above
Answer:
d) is an activator and an ortho/para- director
Explanation:
We options for this question are:
a) is a deactivator and an ortho/para- director
b) is a deactivator and a meta-director
c) is an activator and a meta-director
d) is an activator and an ortho/para- director
e) is an activator and an ortho/meta/para director
f) none of the above
We have to remember that Cl is a halogen, therefore a lone pair of electrons will be involved in the resonance (see figure 1). So, we will have activation in the ortho and para positions. We have to take into account that the halogens have a high electronegativity. This means that inductively they are electron-withdrawing. So, we will have opposite phenomenons that will result in very weak activation
Calculate the heat change in kilojoules for condensation of 195 g of steam at 100 ° C
Answer:
Q = 81.59kJ
Explanation:
Hello,
The heat of condensation is the energy required to to convert the steam into water.
Mass = 195g
Specific heat capacity of water = 4.184J/g°C
Initial temperature(T1) = 100°C
Final temperature(T2) = 0°C
Heat energy (Q) = ?
Heat energy (Q) = mc∇T
M = mass of the substance
C = specific heat capacity of the substance
∇T = T2 - T1 = change in temperature of the substance
Q = 195 × 4.184 × (0 - 100)
Q = -81588J
Q = -81.588kJ
The heat required for the condensation of 195g of steam is 81.59kJ
Please what's the missing minor products? And kindly explain in your own words how they were formed. Thank you!
Answer:
it's a two step elimination reaction
Explanation:
it follows a carbocationic pathway. When carbocation is stable, the equation is favourable, that is, double bond is formed by expelling hydrogen atom.
A solution of benzene in methanol has a transmittance of 93.0 % in a 1.00 cm cell at a wavelength of 254 nm. Only the benzene absorbs light at this wavelength, not the methanol. What will the solution's transmittance be if it is placed in a 10.00 cm long pathlength cell
Answer:
T = 48.39%
Explanation:
In this case we need to apply the Beer law which is the following:
A = CεL (1)
Where:
A: Absorbance of solution
C: Concentration of solution
ε: Molar Absortivity (Constant)
L: Length of the cell
Now according to the given data, we have transmittance of 93% or 0.93. We can calculate absorbance using the following expression:
A = -logT (2)
Applying this expression, let's calculate the Absorbance:
A = -log(0.93)
A = 0.03152
Now that we have the absorbance, let's calculate the concentration of the solution, using expression (1).
A = CεL
C = A / εL
Replacing:
C = 0.03152 / 1 *ε (3)
Now, we want to know the transmittance of the solution with a length of 10 cm. so:
A = CεL
Concentration and ε are constant, so:
A = (0.03152 / ε) * ε * 10
A = 0.3152
Now that we have the new absorbance, we can calculate the new transmittace:
T = 10^(-A)
T = 0.4839 ----> 48.39%
An empty beaker is weighed and found to weigh 23.1 g. Some potassium chloride is then added to the beaker and weighed again. The second weight is 24.862 g. What is the mass of the potassium chloride
Answer:Mass of Potassium chloride =1.762g
Explanation:
Mass of empty beaker = 23.100 g
Mass of beaker with Potassium chloride = 24.862g
Mass of Potassium chloride = Final weight - initial weight = Mass of beaker with Potassium chloride - Mass of empty beaker = 24.862-23.100 = 1.762g
With methyl, ethyl, or cyclopentyl halides as your organic starting materials and using any needed solvents or inorganic reagents, outline syntheses of each of the following. More than one step may be necessary and you need not repeat steps carried out in earlier parts of this problem. (a) CH3I (b) I (c) CH3OH (d) OH (e) CH3SH (f) SH (g) CH3CN (h) CN (i) CH3OCH3 (j) OMe
Answer:
In the attachment you can find all the possible chemical reactions.
Some reaction can not be obtained by using alkyl halides because halides are weak leaving group which can leave compound during reaction easily but hydroxyl groups is a strong nucleophile which can not leave compound easily. So we can obtain alcohol from ethyl bromide, but we can not obtain hydroxyl ion from ethyl bromide.
Explanation:
The methyl of ethyl halides as the organic starting materials are using the needed solvents or the inorganic reagents. These can be not repeated in steps that arrive out in earlier parts.
The reaction can not be taken by the use of alkyl halides as the halides are the weakest leaving group which leave the compound during reaction easily.the hydroxyl group is the strong nucleophile that cannot leave the compound easily. Thus we can get alcohol from the ethyl bromide, but we can not obtain the hydroxyl ion from the ethyl bromide.Learn more about the methyl or the cyclopentyl.
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Tubes through which water flows as it is brought from 0.8 MPa, 150C to 240C at essentially constant pressure in the boiler of a power plant. The total mass flow rate of the water is 100 kg/s. Combustion gases passing over the tubes cool from 1067 to 547C at essentially constant pressure. The combustion gases can be modeled as air as an ideal gas. There is no significant heat transfer from the boiler to its surroundings. Surrounding (dead state) temperature and pressure are given as 25C and 1 atm, respectively. Determine i) the exergetic efficiency of the boiler ii) rate of exergy destruction as kW iii) mass flow rate of the combustion gases as kg/s
Answer:
The correct answer is i) 50.2 % ii) 13440.906 kW and iii) 71.986 kg/s.
Explanation:
In order to find the mass flow rate of the combustion of gases, there is a need to use the energy balance equation:
Mass of water × specific heat of water (T2 -T1)w = mass of gas × specific heat of gas (T2-T1)g
100 × 4.18 × [(240 + 273) - (150 + 273)] = mass of gas × 1.005 × [(1067+273) - (547+273)]
Mass of gas = 71.986 kg/s
The entropy generation of water can be determined by using the formula,
(ΔS)w = mass of water × specific heat of water ln(T2/T1)w
= 100 × 4.18 ln(513/423)
= 80.6337 kW/K
Similarly the entropy generation of water will be,
(ΔS)g = mass of gas × specific heat of gas ln(T2/T1)g
= 71.986 × 1.005 ln (820/1340)
= -35.53 kW/K
The rate of energy destruction will be,
Rate of energy destruction = To (ΔS)gen
= T₀ [(ΔS)w + (ΔS)g]
= (25+273) [80.6337-53.53)
Rate of energy destruction = 13440.906 kW
The availability of water will be calculated as,
= mass of water (specific heat of water) [(T₁-T₂) -T₀ ln T₁/T₂]
= 100 × 4.8 [(513-423) - 298 ln 513/423]
= 13591.1477 kW
The availability of gas will be calculated as,
= mass of gas (specific heat of gas) [(T₁-T₂) - T₀ ln T₁/T₂]
= 71.986 × 1.005 × [(1340-820) - 298 ln 1340/820]
= 27031.7728 kW
The exergetic efficiency can be calculated as,
= Gain of availability / loss of availability
= 13591.1477/27031.7728
= 0.502
The exergetic efficiency is 50.2%.
Give the characteristic of a zero order reaction having only one reactant. a. The rate of the reaction is not proportional to the concentration of the reactant. b. The rate of the reaction is proportional to the square of the concentration of the reactant. c. The rate of the reaction is proportional to the square root of the concentration of the reactant. d. The rate of the reaction is proportional to the natural logarithm of t
Answer:
a. The rate of the reaction is not proportional to the concentration of the reactant.
Explanation:
The rate expression for a zero order reaction is given as;
A → Product
Rate = k[A]⁰
[A]⁰ = 1
Rate = K
GGoing through the options;
a) This is correct because in the final form of the rate expression, the rate is independent of the concentration.
b) This option is wrong
c) This option is also wrong
d) Like options b and c this is also wrong becaus ethere is no relationship between either the concentration or t.
Methane (CH4) and the perchlorate ion (ClO4â) are both described as tetrahedral. Methane and the perchlorate ion are both described as tetrahedral. What does this indicate about their bond angles?
a. Bond angles in the methane molecule are greater than those in the perchlorate ion.
b. Bond angles in the perchlorate ion are greater than those in the methane molecule.
c. Bond angles in the methane molecule and in the perchlorate ion are approximately equal
Answer:
c
Explanation:
The correct answer would be that the bond angles in the methane molecule and in the perchlorate ion are approximately equal.
A tetrahedral shape or geometry means both molecules are sp3 hybridized with the hydrogen atoms and the oxygen ions surrounding the central carbon and chlorine atoms respectively being as far away from one another as possible. This results in an approximate angle of 109.5 degrees in both molecules.
The correct option is c.
Suppose that you add 27.6 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.69 oC compared to pure benzene. What is the molar mass of the unknown compound
Answer:
The molar mass of the unknown compound is 153.3 g/mol
Explanation:
Step 1: Data given
Mass of an unknown molecular compound = 27.6 grams
Mass of benzene = 0.250 kg
Kf of benzene = 5.12 °C/m
freezing point depression of 3.69 °C
Step 2: Calculate molality
ΔT = i*Kf*m
⇒with ΔT = reezing point depression of 3.69 °C
⇒with i = the van't Hoff factor of Benzene = 1
⇒with Kf = 5.12 °C/m
⇒ with m = molality = moles unknown compound / mass of benzene
3.69 = 1 * 5.12 * m
m = 0.72 molal
Step 3: Calculate moles of the unknown compound
molality = moles / mass benzene
0.72 molal = moles / 0.250 kg
Moles = 0.72 m * 0.250 kg
Moles = 0.18 moles
Step 4: Calculate molar mass of the unknown compound
molar mass = mass / moles
Molar mass = 27.6 grams / 0.18 moles
Molar mass = 153.3 g/mol
The molar mass of the unknown compound is 153.3 g/mol
Molar mass is the mass of the one mole of substance. The molar mass of the given unknown compound is 153.3 g/mol.
Molality of the compound can be calculated using
ΔT = i Kf m
Where,
ΔT = freezing point depression = 3.69 °C
i = Van't Hoff factor of Benzene = 1
Kf = constant of freezing = 5.12 °C/m
m = molality = ?
Put the values in the equation,
3.69 = 1 x 5.12 x m
m = 0.72 molal
Number of moles of the compound,
[tex]\bold {molality =\dfrac { moles} { mass\ benzene}}\\\\\bold {0.72\ molal = \dfrac {moles }{0.250\ kg}}\\\\\bold {Moles = 0.72\ m \times 0.250\ kg}\\\\\bold {Moles = 0.18}[/tex]
So, molar mass of the unknown compound,
[tex]\bold {Molar\ mass =\dfrac { mass}{ moles}}\\\\\bold {Molar\ mass = \dfrac {27.6\ grams }{0.18\ moles}}\\\\\bold {Molar\ mass = 153.3 g/mol}[/tex]
The molar mass of the given unknown compound is 153.3 g/mol.
To know more about molar mass,
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A tissue sample at 275 K is submerged in 2 kg of liquid nitrogen at 70 K for cryopreservation. The final temperature of the nitrogen is 75 K. What is the heat capacity of the sample in J/K
Answer:
heat capacity of the sample = 37.8 J/K
Explanation:
Step 1: Data given
Temperature of the sample = 275 K
The mass of liquid nitrogen = 2kg
temperature of liquid nitrogen = 70 K
The final temperature of the nitrogen is 75 K
Step 2: Calculate heat
Q = m*c*ΔT
⇒with m = the mass of liquid nitrogen = 2 kg = 2000 grams
⇒with c= the specific heat of the liquid nitrogen = 1.04 J/g*K
⇒with ΔT = the change of temperature of liquid nitrogen = T2 - T1 = 75 - 70 = 5K
Q = 2000 grams * 1.04 J/g*K * 5K
Q = 10400 J
Step 3: Calculate the heat capacity of the sample
heat capacity of the sample = 10400 J / 275 K
heat capacity of the sample = 37.8 J/K
g The atomic mass of an element is equal to ________. The atomic mass of an element is equal to ________. its mass number one-twelfth of the mass of a carbon-12 atom a weighted average mass of all of the naturally occurring isotopes of the element its atomic number the average mass of all of the naturally occurring isotopes of the element
Answer:
Total numbe of protons and neutrons in a single atom of that element
Explanation:
Hello,
I'll answer the question by filling in the blank spaces
"The atomic mass of an element is equal to the total number of proton and neutron in a particular atom of the element. The atomic mass of an element is equal to the atomic weight. Its mass number one-twelfth of the mass of carbon-12 atom a weighted mass of all naturally occurring isotopes of the elements. Its atomic mass is the average mass of all the naturally occurring isotopes of the element."
The atomic mass of an element is the total number of protons and neutrons in a single atom of that element.
The atomic mass of an element is equal to a weighted average mass of all of the naturally occurring isotopes of the element. The correct answer is option 2.
Isotopes are elements with the same number of protons (atomic number) but differing numbers of neutrons (mass number).
Most elements exist in nature as a mixture of isotopes, each with a different mass number and abundance. The atomic mass of an element is computed by adding the masses of all isotopes, multiplying by their relative abundance, and dividing by the total abundance of all isotopes.
This gives a weighted average mass that corresponds to the normal mass of an element's atom in nature.
Therefore, the correct answer is option 2. to a weighted average mass of all of the naturally occurring isotopes of the element.
Learn more about isotopes here:
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A sample of krypton gas occupies a volume of 9.87 L at 51°C and 0.565 atm. If it is desired to decrease the volume of the gas sample to 8.05 L, while increasing its pressure to 0.678 atm, the temperature of the gas sample at the new volume and pressure must be___________ °C.
Answer:
44.1°C
Explanation:
Step 1:
Data obtained from the question include:
Initial volume (V1) = 9.87 L
Initial temperature (T1) = 51°C = 51°C + 273 = 324K
Initial pressure (P1) = 0.565 atm
Final volume (V2) = 8.05 L
Final pressure (P2) = 0.678 atm
Final temperature (T2) =..?
Step 2:
Determination of the new temperature of the gas.
The new temperature of the gas can be obtained by using the general gas equation as shown below:
P1V1 /T1 = P2V2 /T2
0.565 x 9.87/324 = 0.678 x 8.05/T2
Cross multiply
0.565 x 9.87 x T2 = 324 x 0.678 x 8.05
Divide both side by 0.565 x 9.87
T2 = (324 x 0.678 x 8.05)/(0.565 x 9.87)
T2 = 317.1K
Step 3:
Conversion of 317.1K to decree celsius.
This is illustrated below:
T (°C) = T(K) – 273
T (K) = 317.1K
T (°C) = 317.1 – 273
T (°C) = 44.1°C
Therefore, the new temperature of the gas is 44.1°C
17. Write the molecular balanced equation for the recovering of copper metal. 18. Write the complete ionic balanced equation for the recovering of copper metal. 19. Write the net ionic balanced equation for the recovering of copper metal. 20. What type of reaction is this
Answer:
Explanation:
17. it goes from solid copper to aqueous copper:
Cu(s) --> Cu₂(aq) + 2e⁻
18. complete ionic:
Cu(s) --> Cu₂(aq) + 2e⁻
19. net ionic, must include only reacting species, so
Cu(s) --> Cu₂(aq) + 2e⁻
20. this type of reaction is dissolution reaction(redox reaction)
copper reduced from Cu²⁺ to Cu.
Which scenario describes an interaction between two of Earth's spheres?
Water flows from a stream to a lake.
Gravity moves rocks to another location.
Lions use energy to catch other animals for food.
Bears dig big holes in the ground to protect their young.
The correct answer is D. Bears dig big holes in the ground to protect their young
Explanation:
The Earth spheres include the biosphere (life in the Earth), the hydrosphere (water bodies), the geosphere (rocks and other elements that compose land and soil), and the atmosphere (gases that compose the air). In this context, there is an interaction between two spheres: the biosphere and the geosphere, when a bear digs holes in the ground because a living organism that is part of the biosphere is modifying the structure and shape of superficial soil, which is part of the geosphere.
Answer: D
Explanation:
Question 1
1 pts
2B+6HCI --
| --> 2BCl3 + 3H2
How many moles of boron chloride will be produced if you start with 8.752 moles of HCI
(hydrochloric acid)? (Round to 3 sig figs. Enter the number only do not include units.)
Answer:
2.92 mol
Explanation:
Step 1: Write the balanced equation
2 B(s) + 6 HCI(aq) ⇒ 2 BCl₃(aq) + 3 H₂(g)
Step 2: Establish the appropriate molar ratio
The molar ratio of hydrochloric acid to boron chloride is 6:2.
Step 3: Calculate the moles of boron chloride produced from 8.752 moles of hydrochloric acid
[tex]8.752molHCl \times \frac{2molBCl_3}{6molHCl} = 2.92molBCl_3[/tex]