Answer:
a. [tex]Al(OH)_3(s)+3H^\rightarrow Al^{3+}+3H_2O(l)\\[/tex]
b. [tex]Pb^{2+}(aq)+2I^-(aq)\rightarrow PbI_2(s)[/tex]
Explanation:
Hello,
a. In this case, the overall reaction is:
[tex]Al(OH)_3(s)+3HBr(aq)\rightarrow AlBr_3(aq)+3H_2O[/tex]
Nevertheless, the ionic version is:
[tex]Al(OH)_3(s)+3H^++3Br^-(aq)\rightarrow Al^{3+}+3Br^-(aq)+3H_2O(l)\\[/tex]
Since the base is insoluble, thereby, the balanced net ionic equation turns out:
[tex]Al(OH)_3(s)+3H^\rightarrow Al^{3+}+3H_2O(l)\\[/tex]
Since bromide ions become spectator ions.
b) In this case, the overall reaction is:
[tex]Pb(NO_3)_2(aq)+2LiI(aq)\rightarrow PbI_2(s)+2LiNO_3(aq)[/tex]
Nevertheless, the ionic version is:
[tex]Pb^{2+}(aq)+2(NO_3)^-(aq)+2Li^+(aq)+2I^-(aq)\rightarrow PbI_2(s)+2Li^+(aq)+2(NO_3)^-(aq)[/tex]
Since lead (II) iodide is insoluble whereas lithium nitrate does not, thereby, the net ionic equation turns out:
[tex]Pb^{2+}(aq)+2I^-(aq)\rightarrow PbI_2(s)[/tex]
Since lithium and nitrate ions become spectator ions.
Regards.
Calculate the work (kJ) done during a reaction in which the internal volume expands from 28 L to 51 L against an outside pressure of 4.9 atm.
Answer:
W= -11KJ
Explanation:
Given:
volume expands from 28 L to 51 L
pressure =4.9 atm.
We will need to Convert the pressure to Pascal SI
But 1 atm = 101,325 Pa.
Then,
Pressure= (4.9*101323)/1atm = 5*10^5 pa
Then we need to Convert the volumes to cubic meters
But we know that1 m³ = 1,000 L.
V1= 28L * 1m^3/1000L = 0.028m^3
V2=51L × 1m^3 /1000L =0.051m^3
The work done during the expansion of a gas can be calculated as
W= -P(V2-V1)
W= - 5*10^5(0.051m^3 - 0.028m^3)
W= -1.1× 10^4J
Then we can Convert the work to kiloJoule
But1 kJ = 1,000 J.
W= -1.1× 10^4J× 1kj/1000J
= -11KJ
How many hours does it take to form 15.0 L of O₂ measured at 750 torr and 30°C from water by passing 3.55 A of current through an electrolytic cell?
Answer:
The correct answer is 17.845 hours.
Explanation:
To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.
Based on Faraday's law, m = Mit/nF
Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).
From the above mentioned equation,
t = mnF/Mi ------(i)
Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.
So, from the above gas law's equation, m = PVM/RT
Now putting the values of m in the equation (i) we get,
t = PVMnF/MiRT = PVnF/iRT
Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.
1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.
Now putting the values we get,
t = PVnF/iRT
= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K
= 64243.81 secs or 64243.81/3600 hr
= 17.845 hours
2. A student has a centrifuge tube containing 14.0 g of t-butanol and is asked to make a 1.2 m solution of ethanol/t-butanol. How much ethanol would the student need to add in mL and in g? Show your calculations. Show your calculations. (6 pts)
Answer:
0.774g of ethanol
0.970mL of ethanol
Explanation:
Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.
In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).
14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:
0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol
To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:
0.0168moles Ethanol ₓ (46.07g / mol) =
0.774g of ethanolAnd to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):
0.774g ₓ (1mL / 0.798g) =
0.970mL of ehtanolPhosphorus pentachloride decomposes to phosphorus trichloride at high temperatures according to the equation:
PCl5(g) = PCl3(g) + Cl2(gu)
at 250 Co , 0.125M PCl5 is added to the flask , if Kc=1.80, what are the equilibrium concentrations of each gas?
A) [PCl5]=0.0625M,[PCl3]=0.0335M,and [Cl2]=0.335M
B) [PCl5]=1.80M,[PCl3]=1.80M,and [Cl2]=1.80M
C) [PCl5]=0 M,[PCl3]=1.34M,and [Cl2]=1.34M
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M
E) [PCl5]=3.96M,[PCl3]=3.83M,and [Cl2]=3.83M
Answer:
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117M
Explanation:
Based on the reaction:
PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)
And knowing:
Kc = [PCl₃] [Cl₂] / [PCl₅] = 1.80
When you add PCl₅ into a flask, this gas will react producing PCl₃ and Cl₂ until [PCl₃] [Cl₂] / [PCl₅] = 1.80
This could be written as:
[PCl₃] = X
[Cl₂] = X
[PCl₅] = 0.125M - X
Where X represents the moles of PCl₅ that react, reaction coordinate.
Replacing in Kc expression:
[PCl₃] [Cl₂] / [PCl₅] = 1.80
[X [X] / [0.125 - X] = 1.80
X² = 0.225 - 1.80X
0 = -X² -1.80X + 0.225
Solving for X:
X = -1.9M → False solution, there is no negative concentrations
X = 0.11735M → Right solution.
Replacing, concentrations in equilibrium are:
[PCl₃] = X
[Cl₂] = X
[PCl₅] = 0.125M - X
[PCl₃] = 0.117M
[Cl₂] = 0.117M
[PCl₅] = 0.00765M
And right option is:
D) [PCl5]=0.00765M,[PCl3]=0.117M,and [Cl2]=0.0.117MIn the naturally occurring D series of ketoses, the carbonyl group is found on carbon number ___________, whereas in aldoses, the carbonyl group is found on carbon number _________.
Answer:
second carbon atom from the end
end carbon atom
Explanation:
Carbohydrates are naturally occurring organic compounds containing carbon, hydrogen and oxygen. The general molecular formula of Carbohydrates is [tex]C_x(H_2O)_y[/tex].
Carbohydrates can be classified based on structures,
Carbohydrates with the structure of alkanals (-CHO) are known as aldose while those of the structure of alkanones (C=O) are known as ketose.
In stereochemistry , D series is a kind of configurational arrangement where the hydroxyl group attaches itself to the right hand side.
Thus; in naturally occurring D series of ketoses, the carbonyl group is found on carbon number second carbon atom from the end whereas in aldoses, the carbonyl group is found on carbon number end carbon atom.
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 178C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
A) The specific humidity of the air with the given parameters is;
w1 = 0.00967
B) The relative humidity of the air with the given parameters is;
Φ1 = 0.459
C) The enthalpy of the air in KJ/kg dry air with the given parameters is;
h1 = 49.75 KJ/Kg
Correct question is;
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
We are given;
Atmospheric Pressure;P = 95 KPa
Dry temperature;T1 = 25 °C
Wet temperature;T2 = 17°C
A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa
First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;
w2 = (0.622 × P_g2)/(P - P_g2)
w2 = (0.622 × 1.938)/(95 - 1.938)
w2 = 0.013
Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;
h_fg2 = 2460 KJ/Kg
h_g1 = 2546.5 KJ/Kg
h_f2 = 71.36 KJ/Kg
The formula for the specific humidity under these conditions is;
w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)
c_p of air has a value of 1.005 KJ/Kg.°C
Thus;
w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)
w1 = 0.00967
B) The relative humidity is determined from the equation;
Φ1 = (w1*p)/(0.622 + w1)p_g1
From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa
Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698
Φ1 = 0.459
C) For the enthalpy of air, h1 we will use the formula;
h1 = (c_p × T1) + (w1 × h_g1)
h1 = (1.005 × 25) + (0.00967 × 2546.5)
h1 = 49.75 KJ/Kg
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on the basis of Le chatelier's Principle explain why the addition of Solid NH4Cl to a saturated solution of Mg(OH)2 in water causes more of the Mg(OH)2 to dissolv
Explanation:
Le Chetelier's principle states that in an equilibrium system, if a constraint (such as a change in pressure, temperature, or concentration of a reactant) is applied to the system, the equilibrium will shift so as to tend to annul the effect of the constraint. For the dissolution of Solid Magnesium oxide Mg(OH)2 in water, normally, only a small amount of the solid is dissolved to form magnesium ions Mg^2+ and hydroxide ions 2OH-. In a saturated solution of magnesium oxide in water, any action that removes the hydroxide ions formed will cause the reaction to shift to the product side on the right to favor the production of more hydroxide ion, which means more of the magnesium oxide will be dissolved.
Addition of Ammonium chloride NH4Cl neutralizes the hydroxide ions by acting as an acid, to form ammonia NH3 and water H20. This is because the Ammonium chloride dissolves to form ammonium NH4 and chlorine Cl^- ions in the solution, allowing the ammonium to react with the hydroxide ions. The reactions are shown below.
Mg(OH)2 ⇄ Mg^2+ 2OH^- ....... initial magnesium oxide dissolution
NH4Cl ⇒ NH4 + Cl ......... dissolution of ammonium chloride
NH4 + OH^- ⇒ NH3 + H2O ....... the consumption of the hydroxide ion by the ammonium to form ammonia and water, leading to more of the magnesium oxide dissolving to form more hydroxide ions.
A mixture with H2 and He exerts a total pressure of 0.48 atm. If there is 1.0 g of H2 and 1.0 g of He in the mixture, what is the partial pressure (in atmospheres) of hydrogen?
Answer:
Partial pressure of hydrogen H₂ = 0.32 atm
Explanation:
Given:
Total pressure = 0.48 atm
Find:
Partial pressure of hydrogen
Computation:
Number of mole of H₂ = 1 / 2 = 0.5 moles
Number of mole of He = 1 / 4 = 0.25 moles
Total moles = 0.5 + 0.25 = 0.75
Partial pressure of hydrogen H₂ = [moles / total moles] Total pressure
Partial pressure of hydrogen H₂ = [0.50 / 0.75]0.48 atm
Partial pressure of hydrogen H₂ = 0.32 atm
Answer: 0.32 atm
Explanation:
First convert the mass of H2 to moles using the molar mass.
(1.0 gram H2 ⋅ (1.0 mol H2 / 2.016 g H2)) ≈ 0.50 mol H2
Next, convert the mass of helium He to moles using the atomic mass.
(1.0 gram He ⋅ (1.0 mol He / 4.003 g He)) ≈ 0.25mol He
The total number of moles is about 0.75 moles . The partial pressure of a component of a gas mixture can be found by multiplying the mole fraction by the total pressure.
PH2 = XH2 × Ptotal
PH2 = (0.50 mol / 0.75 mol)(0.48 atm) = 0.32 atm
If the NaOH is added to 35.0 mL of 0.167 M Cu(NO3)2 and the precipitate isolated by filtration, what is the theoretical yield of the reaction?
Answer:
The correct answer is - 0.570 grams
Explanation:
The balanced chemical reaction is given by
Cu(NO3)2(aq) + 2NaOH(aq) --------> Cu(OH)2(s) + 2NaNO3(aq)
1.0 mole 2.0 mole 1.0 mole 2.0 mole
number of mol of Cu(OH)2,
n = Molarity * Volume
= [tex]35.0*0.167 = 5.845[/tex] millimoles
As clear in the equation, 1 mole of Cu(NO3)2 gives 1 mole of Cu(OH)2 , So, 5.845 millimoles of Cu(NO3)2 will produce 5.845 millimoles of Cu(OH)2
Mass of Cu(OH)2 = number of mol * molar mass
= [tex]97.5*5.845*10^-3[/tex]
= 0.570 grams
Thus, the correct answer is - 0.570 grams
How many water molecules are in a block of ice containing 0.500 mol of water (H2O)?
Answer:
3.01 × 10²³ molecules
Explanation:
Step 1: Given data
Moles of water (n): 0.500 mol
Step 2: Calculate the molecules of water present in 0.500 moles of water
In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.
0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules
the reation between sulfur dioxide and oxygen is a dynamic equilibrium. what happens when the pressure of the system is
increased ?
Answer:
In the above reaction, sulfur dioxide and oxygen react together to form sulfur trioxide. This means that an increase in pressure would move the equilibrium to the right and result in more sulfur trioxide being formed. Pressure can only affect the position of equilibrium if there is a change in the total gas volume.
Which of the possible compounds has a mass of 163 grams when
6.13 x 1024 molecules of the compound is put on a scale?
Answer:
CH4
Explanation:
In solving this problem, we must remember that one mole of a compound contains Avogadro's number of elementary entities. These elementary entities include atoms, molecules, ions etc. Recall that one mole of a substance is the amount of substance that contains the same number of elementary entities as 12g of carbon-12. The Avogadro's number is 6.02 × 10^23.
Hence we can now say;
If 163 g of the compound contains 6.13 ×10^24 molecules
x g will contain 6.02 × 10^23 molecules
x= 163 × 6.02 × 10^23 / 6.13 × 10^24
x= 981.26 × 10^23/ 6.13 ×10^24
x= 160.1 × 10^-1 g
x= 16.01 g
x= 16 g(approximately)
16 g is the molecular mass of methane hence x must be methane (CH4)
Which one of the following would have the largest dispersion forces?
A) CH3CH2SH
B) CH3NH2
C) CH4
D) CH3CH3
Answer:
A) CH3CH2SH
Explanation:
Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.
Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.
Now; for option (A)
CH3CH2SH
The molar mass is :
= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)
= (12 + 3+ 12 + 2 + 32 + 1)
= 62 g/mol
For option (B)
CH3NH2
The molar mass is:
= (12 + (1 × 3 ) +14 + (1 × 2)
= (12 + 3 + 14 + 2)
= 31 g/mol
For option (C)
CH4
The molar mass is :
= 12 + (1 × 4)
= 12 + 4
= 16 g/mol
For option (D)
CH3CH3
The molar mass is :
= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)
= 12 + 3 + 12 + 3
= 30 g/mol
Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH
A 2.0 g sample of hydrocarbon was burned in the calorimeter. The temperature rose from 29°c to 32°c and heat and combustion is 11. Kj/g. Thr heat capacity of the calorimeter is
Answer:
THE HEAT CAPACITY OF THE CALORIMETER IS 3666.67 J/C
Explanation:
Mass = 2 g
Temperature difference = 32 C - 29 C = 3 C
Heat of combustion = 11 kJ/g
Heat capacity of the calorimeter = unknown
It is important to note that the heat of combustion of the reaction is the heat absorbed by the calorimeter in raising the mixture by 3 C
So therefore,
Heat = heat capacity * temperature difference
Heat capacity = Heat / temperature difference
Heat capacoty = 11 000 J / 3 C
Heat capacity = 3666.67 J/ C
How many moles of CO are produced when 1.2 moles C reacts? Equation: 5C(s)+2SO2(g)→CS2(l)+4CO(g)
Answer:
0.96 mol CO
Explanation:
We simply just use the reaction to help us find this:
[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]
Multiply it out and we get 0.96 as our answer.
Which of the following functional groups is not present in the HIV protease inhibitor drug below called Saquinavir?
A) alcohol
B) amide
C) aromatic ring
D) amine
E) ketone N. ○ ト Saquinavir Structure
Answer:
alcohol
Explanation:
Since in its chemical structure it presents an amide, amine and aromatic ring group.
What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.
g A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. If the radiation wavelength is 12.5 cm, how many photons of this radiation would be required to heat a container with 0.250 L of water from a temperature of 20.0oC to a temperature of 99oC
Answer:
The total photons required = 5.19 × 10²⁸ photons
Explanation:
Given that:
the radiation wavelength λ= 12.5 cm = 0.125 m
Volume of the container = 0.250 L = 250 mL
The density of water = 1 g/mL
Density = mass /volume
Mass = Volume × Density
Thus; the mass of the water = 250 mL × 1 g/mL
the mass of the water = 250 g
the specific heat of water s = 4.18 J/g° C
the initial temperature [tex]T_1[/tex] = 20.0° C
the final temperature [tex]T_2[/tex] = 99° C
Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C
The heat q absorbed during the process = ms [tex]\Delta T[/tex]
The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C
The heat q absorbed during the process = 82555 J
The energy of a photon can be represented by the equation :
= hc/λ
where;
h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]
c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]
= [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]
= [tex]1.59024 \times 10^{-24}[/tex] J
The total photons required = Total heat energy/ Energy of a photon
The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]
The total photons required = 5.19 × 10²⁸ photons
Grams of cl in 38g of cf3cl
Answer:
114 grams
Explanation:
3chlorines per compound*38grams=114
Calculate the energy of a photon of electromagnetic radiation at each of the following wavelengths.
a. 632.8 nm (wavelength of red lightfrom helium-neon laser)
b. 503 nm (wavelength of maximumsolar radiation)
c. 0.0520 nm (a wavelength contained inmedical X-rays)
Answer:
A)566×10^-16J
B)711.99×10^-16J
C)688.69×10^-12J
Explanation:
A)
But we know that
1 nm = 10^-9 m
Then we can Convert from nanometer to metre which is SI unit
632.8 nm = 632.8×10^-9 m = 6.328×10^-7 m
The speed of light is c = 2.998×10^8 m/s
λ = 6.328×10^-7 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (6.328×10^-7 m)
Then
ƒ = 4.738×10^14 s-1
To calculate Energy we use
Energy= hf
Where h is plank constant= 6.626× 10^-34
Energy= 6.626× 10^-34 × 4.738×10^14=566×10^-16J
B)
But we know that
1 nm = 10^-9 m
Then we can Convert from nanometer to metre which is SI unit
Then 503 nm = 503×10^-9 m = 5.03×10^-7 m
c = 2.998×10^8 m/s
λ = 5.03×10^-7 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (5.03×10^-7 m)
ƒ = 5.960×10^14 s-1
Energy= 6.626× 10^-34 × 5.960×10^14 s-1= 711.99×10^-16J
C)
1 nm = 10^-9 m
0.0520 nm = 0.0520×10^-9 m = 5.20×10^-11 m
Where the speed of light is
c = 2.998×10^8 m/s
λ = 5.20×10^-11 m
But the frequency can be calculated as;
ƒ = c / λ
ƒ = (2.998×10^8 m/s) / (5.20×10^-11 m)
ƒ = 5.765×10^18 s-1
Energy= 6.626× 10^-34 × 5.765×10^18 s-1= 688.69×10^-12J
Platinum can be found in which of the following formations
A.Sedimentary Bands
B. Aggregates
C. Chromite Bands
D. Hydrothermal Veins
Answer:
Explanation:
D
For a given sample of C3H8(g), the enthalpy change during the reaction is -784kJ. How many grams of CO2 are produced? Group of answer choices g
Answer:
[tex]m_{CO_2}=46.6gCO_2[/tex]
Explanation:
Hello,
In this case, considering the combustion of propane:
[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)\ \ \ \Delta _CH=-2220.0 kJ/mol[/tex]
We can compute the burnt moles of propane as shown below:
[tex]n=\frac{-784kJ}{-2220.0 kJ/mol} =0.353molC_3H_8[/tex]
Then, by noticing propane and carbon dioxide are in a 1:3 molar ratio, we can compute the grams carbon dioxide by using the shown below stoichiometric procedure:
[tex]m_{CO_2}=0.353molC_3H_8*\frac{3molCO_2}{1molC_3H_8} *\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=46.6gCO_2[/tex]
Best regards.
Which aqueous solution will have the highest boiling point temperature? A. 0.100 molal NiBr2(aq) B. 0.250 molal CH3OH(aq) C. 0.100 molal MgSO4(aq) D. 0.150 molal Na2SO4(aq) E. 0.150 molal NH4NO3(aq)
Answer: 0.150 m [tex]Na_2SO_4(aq)[/tex] will have highest boiling point.
Explanation:
Formula used for Elevation in boiling point :
[tex]\Delta T_b=i\times k_b\times m[/tex]
where
[tex]\Delta T_b=T_b-T^o_b[/tex]= elevation in boiling point
[tex[k_b[/tex] = boiling point constant
m = molality
i = Van't Hoff factor
A) 0.100 m [tex]NiBr_2[/tex]
i = 3 as [tex]NiBr_2\rightarrrow Ni^{2+}+2Br^-[/tex]
concentration will be [tex]3\times 0.100=0.300[/tex]
B) 0.250 m [tex]CH_3OH[/tex]
i = 1 as [tex]CH_3OH[/tex] is a non electrolyte
concentration will be [tex]1\times 0.250=0.250[/tex]
C) 0.100 molal [tex]MgSO_4(aq)[/tex]
i = 2 as [tex]MgSO_4\rightarrrow Mg^{2+}+SO_4^{2-}[/tex]
concentration will be [tex]2\times 0.100=0.200[/tex]
D. 0.150 molal [tex]Na_2SO_4(aq)[/tex]
i = 3 as [tex]Na_2SO_4\rightarrrow 2Na^{+}+SO_4^{2-}[/tex]
concentration will be [tex]3\times 0.150=0.450[/tex]
E. 0.150 molal [tex]NH_4NO_3(aq)[/tex]
i = 2 as [tex]NH_4NO_3\rightarrrow NH_4^{+}+NO_3^{-}[/tex]
concentration will be [tex]2\times 0.150=0.300[/tex]
The solution having the highest concentration of ions will have the highest boiling point and thus 0.150 m [tex]Na_2SO_4(aq)[/tex] will have highest boiling point.
The aqueous solution that would have the highest temperature at boiling point would be:
D). 0.150 molal Na2SO4(aq)
What is a boiling point?The boiling point is described as the temperature at which the solution starts boiling or the vapor pressure becomes equivalent to the provided external/outer pressure.
To determine the elevation in boiling point, we will use:
Δ[tex]T_{b}[/tex] [tex]= i[/tex] × [tex]k_{b}[/tex] × [tex]m[/tex]
with
[tex]T_{b}[/tex] [tex]= T_{b} - T^{0}_{b}[/tex]
[tex]k_b[/tex] [tex]=[/tex] constant of boiling point
Using this formula,
0.150 molal Na2SO4(aq)
Given,
[tex]i = 3[/tex]
[tex]Na2So4[/tex] will have
[tex]2Na^{+}[/tex] [tex]+[/tex] [tex]SO^{2-}_{4}[/tex]
So,
Concentration [tex]= 3[/tex] × [tex]0.15[/tex][tex]0[/tex]
[tex]= 0.45[/tex][tex]0[/tex]
∵ 0.150 molal [tex]Na2SO4[/tex]Na2SO4(aq) has the maximum concentration.
Thus, option D is the correct answer.
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When aqueous solutions of NH4OH(aq) and CuCl2(aq) are mixed, the products are NH4Cl(aq) and Cu(OH)2(s). What is the net ionic equation for this reaction
Answer:
2OH^-(aq) + Cu^2+(aq) -----> Cu(OH)2(s)
Explanation:
The net ionic equation usually shows the main ionic reaction that goes in the system. The other ions that do not participate in this net ionic equation are called spectator ions. Spectator ions do not participate in the main reaction occurring in the system.
The net ionic equation quite often result in the formation of a solid precipitate in the system such as Cu(OH)2.
The net ionic equation for this reaction is;
2OH^-(aq) + Cu^2+(aq) -----> Cu(OH)2(s)
A client with a long history of cigarette smoking and poorly controlled hypertension is
experiencing psychomotor deficits due to hemorrhagic brain damage. Which diagnosis is likely
for the onset of progressive dementia?
Answer:
It may be a hemorrhagic stroke because of the patient's history.
Explanation:
Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain
The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state
(4Ga + 3S2 → 2Ga2S3)
1. How many moles of Sulfur are needed to react with 12.5 moles of Gallium
Answer:
9.375
Explanation:
According to the chemical equation, for every 4 moles of gallium, 3 moles of sodium are needed to react. Set up a ratio using this relationship to solve.
4/3 = 12.5/x
4x = 37.5
x = 9.375
You need 9.375 moles of sulfur.
A sample containing 1.20 moles of Ne gas has an initial volume of 7.50 L. What is the final volume of the gas, in liters, when each of the following changes occur in the quantity of the gas at constant pressure and temperature?
1) a leak allows one half of the Ne atoms to escape
2) a sample of 3.10 moles of Ne is added to the 1.20 moles of Ne gas in the container
3) a sample of 35.0 g of Ne is added to the 1.20 moles of Ne gas in the container.
Answer:
1 = 3.75L
2 = 26.91L
3 = 18.37L
Explanation:
Hello,
The question above can be solved when we know Avogadro's law which states that the volume of a fixed mass of gas is directly proportional the number of moles present provided temperature and pressure are kept constant.
Mathematically,
N = kV k = n/v
N1/V1 = N2/V2 = N3/V3 =......=Nn/Vn
N1 = 1.20 moles
V1 = 7.50L
1) if half of the Ne atoms escaped what would be the final volume.
1 mole of Ne = 6.022×10²³ atoms
½(1.20) moles of Ne = ?
0.6 moles of Ne = ?
1 mole = 6.022×10²³ atom
1.2 moles = ?
x = 1.2 × 6.022×10²³ atoms
x = 7.23×10²³atoms
If ½ of 7.23×10²³ atoms escaped, how many would be left
½ × 7.23×10²³ atoms = 3.61×10²³atoms
Now we have to find the number of moles and then use our equation.
1 mole = 6.022×10²³ atoms
y mole = 3.61×10²³ atom
y = 0.6 mole
N2 = 0.6 mole
N1 / V1 = N2 / V2
Make V2 the subject of formula,
V2 = (N2 × V1) / N1
V2 = (0.6 × 7.50) / 1.20
V2 = 3.75L
The volume after half of the Ne atoms escaped is 3.75L
2)
When a sample of 3.10 mole is added to 1.20 moles present
N1 = 1.20
V1 = 7.51
N2 = (1.20 + 3.10) = 4.30L
V2 = ?
N1 / V1 = N2 / V2
V2 = (N2 × V1) / N1
V2 = (4.30 × 7.51) / 1.20
V2 = 26.91L
The volume of Ne gas if 3.10 moles is added to it is 26.91L
3)
A sample of 35g is added to the 1.20 mole Ne in the container.
We need to convert the mass (35g) to moles. This can be done using mass-molarmass relationships
Number of moles = mass / molar mass
Molar mass of Ne = 20.17g/mol
Number of moles = 35 / 20.17
Number of moles = 1.735 moles
N2 = 1.20 moles + 1.735 moles
N2 = 2.935 moles
N1 / V1 = N2 / V2
V2 = (N2 × V1) / N1
V2 = (2.935 × 7.51) / 1.20
V2 = 18.37L
On addition of 35g of Ne gas to the container, the volume is increased to 18.37L
Which one of the following substances, when dissolved in water at equal molar concentrations, will give the solution with the lowest electrical conductivity
a. CaC12
b. HNO3
c. NH3
d. C6H12O6 (glucose)
e. CO2
The substance which gives more ions in ionization will be more conductive and those giving less ions will be less conducting. Here, glucose only give no ion in water thus, it has the lower conductivity.
What is ionization?Ionization is the process of dissociation of compounds into its constituent ions. For example, HCl when dissolved in water will give H+ and Cl- ions. Similarly HNO₃ gives H+ and NO₃- ions in ionization.
Water can easily dissolves the ionic compounds by forming hydrogen bonds with them and thus easily ionises them The ions formed are mobile and conduct electricity. The more the number of ions the higher the electrical conductivity.
CaCl₂ gives Ca²⁺ and two Cl- ions and NH₃ gives NH₄⁺ ions and CO₂ gives H+ ions by the formation of carbonic acid. Wheres, glucose does not give its ions and thus has lower conductivity for the solution.
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Calculate the amount of heat required to convert 10.0 grams of ice at –20.°C to steam at 120.°C. (Sp. heat of H2O(s) = 2.09 J/g•°C, Sp. heat of H2O(l) = 4.18 J/g•°C, Sp. heat of H2O(gas) = 2.03 J/g•°C; heat of fusion of H2O(solid) = 333 J/g, heat of vaporization of H2O(liquid) = 2260 J/g).
Answer:
THE AMOUNT OF HEAT REQUIRED TO CONVERT ICE FROM -20 C TO STEAM AT 120 C IS 30 946 J OR 30.946 KJ OF HEAT.
Explanation:
Mass = 10 g
To convert 10 g of ice at -20°C to steam at 120°C, the heat involved is:
1. Heat involved in converting the ice from -20 °c to ice at 0 °C:
Heat = mass * specific heat of water solid * change in temperature
heat = 10g * 2.09 J/g°C * ( 0- (-20))
Heat = 10 * 2.09 * 20
heat = 418 J
2. Heat required to convert the ice from 0°C to water at 0°C:
Heat = mass * specific heat of fusion of water solid
Heat = 10 * 333
Heat = 3330 J
3. Heat required to convert water at 0 C to water at 100 C:
Heat = mass * specific heat of water * change in teperature
Heat = 10 * 4.18 * (100 -0)
Heat = 4180 J
4. Heat required to convert water at 100 C to steam at 100 C:
Heat = mass * specific heat of vaporization
Heat = 10 * 2260
Heat = 22600 J
5. Heat required to convert steam from 100 C to steam at 120 C:
Heat = mass * specific heat of water * change in temperature
Heat = 10 * 2.09 * (120 -100)
Heat = 10 * 2.09 * 20
Heat = 418 J
T
he heat required to convert 10 g of ice at -20 C to steam at 120 C is therefore the total of the individual heat of reactions
Total amount of heat = ( 418 J + 3330 J + 4180 J + 22600 J + 418 J)
Total heat = 30946 J
A 25.0 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution. A buffer region was found around a pH of 3.5. The unknown compound is
Answer:
The unknown compound is a weak acid.
Explanation:
Given that :
a 25 mL sample of a solution of an unknown compound is titrated with a 0.115 M NaOH solution.
A buffer region was found around a pH of 3.5. We know that a pH of 3.5 is a weak acid. So, it is likely to be an organic acid
Let assume the solution of the unknown sample to be CH₃COOH
Now :
25 mL of CH₃COOH reacted with 0.115 M of NaOH
The equation for the reaction will be :
CH₃COOH + NaOH -----> CH₃COONa + H₂O
at x mole of 0.115y M of
CH₃COOH NaOH is present
If NaOH was added in excess;
CH₃COOH + NaOH -----> CH₃COONa , NaOH will be lost then CH₃COOH and CH₃COONa will be present
Therefore;
At equilibrium : Only CH₃COONa will be present but if it is above equilibrium NaOH will be present because the pH will increase due to the presence of the strong base
pls answer these questions for brainliest
katya is investigating displacement reactions . She heats the pairs of substances in this list
iron and aluminium oxide
iron and copper oxide
copper and magnesium oxide
iron and lead oxide
a)write down the letters os 2 pairs of substances that react . Explain your choices
b) choose one pair of substances that react . write a word equation for the reaction