Answer:
[tex]m_{Ga_2S_3}=2415.31gGa_2S_3[/tex]
Explanation:
Hello,
In this case, for the given chemical reaction, we can notice there is a 4:2 molar ratio between the burned moles of gallium and the yielded moles of gallium sulfide, therefore, we compute them as shown below:
[tex]n_{Ga_2S_3}=20.5molGa*\frac{2molGa_2S_3}{4molGa}=10.25mol Ga_2S_3[/tex]
Then, by using the molar mass of gallium sulfide (235.64 g/mol), we directly compute the grams:
[tex]m_{Ga_2S_3}=10.25mol Ga_2S_3*\frac{235.64gGa_2S_3}{1molGa_2S_3} \\\\m_{Ga_2S_3}=2415.31gGa_2S_3[/tex]
Best 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
What mass of benzene is cooled from 83.8 °C to 77.1 °C when 167 J of energy is transferred out of the system? (The specific heat of benzene is 1.740 J/g °C).
Answer:
14.32g
Explanation:
Initial temperature = 83.8°C
Final temperature = 77.1°C
Temperature change, ΔT = 83.8°C - 77.1°C = 6.7
Heat, H = 167J
Specific heat, c = 1.740J/g °C
m = ?
All these parameters are related with the equation below;
H = mcΔT
m = H / cΔT
m = 167 / (1.740 * 6.7)
m = 167 / 11.658 = 14.32g
A piece of silver with a mass 368 g has a heat capacity of 87.2 J/°C. What is the specific heat of
silver?
A. 0.385 J/g.°C
B. 0.237 J/g.°C
C. 0.184 J/g.°C
D. 1.322 J/g.°C
E. 4.184 J/g.°C
Answer:
B
Explanation:
Heat capacity = mass x specific heat capacity.
(C = mc)
87.2 = 368 x c
= 0.237 J/g.°C
What volume of a 2.25 M sodium chloride solution will contain 4.58 moles of sodium chloride
(NaCl)?
A. 0.252 L
B. 119 L
C. 5.62 L
D. 0.491 L
E. 2.04 L
Answer:
Option E. 2.04 L
Explanation:
Data obtained from the question include:
Molarity of NaCl = 2.25 M
Mole of NaCl = 4.58 moles
Volume =..?
Molarity is simply defined as the mole of solute per unit litre of the solution. It is represented mathematically as:
Molarity = mole /Volume
With the above formula, we can obtain the volume of the solution as follow:
Molarity = mole /Volume
2.25 = 4.58/volume
Cross multiply
2.25 x volume = 4.58
Divide both side by 2.25
Volume = 4.58/2.25
Volume = 2.04 L
Therefore, the volume of the solution is 2.04 L
help please !!!!!!!!
Answer:
Option B. 2096.1 K
Explanation:
Data obtained from the question include the following:
Enthalpy (H) = +1287 kJmol¯¹ = +1287000 Jmol¯¹
Entropy (S) = +614 JK¯¹mol¯¹
Temperature (T) =.?
Entropy is related to enthalphy and temperature by the following equation:
Change in entropy (ΔS) = change in enthalphy (ΔH) / Temperature (T)
ΔS = ΔH / T
With the above formula, we can obtain the temperature at which the reaction will be feasible as follow:
ΔS = ΔH / T
614 = 1287000/ T
Cross multiply
614 x T = 1287000
Divide both side by 614
T = 1287000/614
T = 2096.1 K
Therefore, the temperature at which the reaction will be feasible is 2096.1 K
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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Which of the following pairings usually forms molecular compounds?
Select the correct answer below:
metal, nonmetal
nonmetal, nonmetal
metal, metal
none of the above
A nonmetal and a nonmetal will make molecular compounds like H2O and CO2
If 0.98 g of an unknown was dissolved in 10.30 g of solvent and the resulting solution has a molality of 0.45 m, what is the molar mass of the unknown
Answer:
211.4g/mol.
Explanation:
Data obtained from the question includes:
Mass of unknown compound = 0.98g
Mass of solvent = 10.30g
Molality = 0.45 M
Next, we shall determine the number of mole of the unknown compound present in the solution.
This can be obtained as follow:
Molality = mole /kg of solvent
Mole of the unknown compound =.?
Mass of solvent = 10.30g = 10.30/1000 = 0.0103Kg
Molality = 0.45 M
Molality = mole /kg of solvent
0.45 = mole /0.0103
Cross multiply
Mole = 0.45 x 0.0103
Mole = 4.635×10¯³ mole
Therefore the mole of the unknown compound that dissolve in solution is 4.635×10¯³ mole
Now, we can obtain the molar mass of the unknown compound as follow:
Mole of the unknown compound = 4.635×10¯³ mole
Mass of unknown compound = 0.98g
Molar mass of the unknown compound =?
Mole = mass /Molar mass
4.635×10¯³ = 0.98 /Molar mass
Cross multiply
4.635×10¯³ x molar mass = 0.98
Divide both side by 4.635×10¯³
Molar mass = 0.98 / 4.635×10¯³
Molar mass = 211.4g/mol.
Therefore, the molar mass of the unknown compound is 211.4g/mol.
The molecular mass of the unknown has been 211.66 g/mol.
Molality can be defined as the moles of the solute per kg of solvent.
Molality can be expressed as:
Molality = [tex]\rm \dfrac{Mass\;of\;solute\;(g)}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{Mass\;of\;solvent\;(g)}[/tex] ......(i)
The given unknown has been the solute.
The mass of solute = 0.98 g.
The mass of solvent = 10.30 g.
The molality of the solution formed has been = 0.45 m.
Substituting the values in equation (i):
0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{10.30\;g}[/tex]
0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;97.087[/tex]
[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex] = [tex]\rm \dfrac{0.45}{97.087}[/tex]
[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex] = 0.00463
Molecular mass of solute = [tex]\rm \dfrac{0.98}{0.00463}[/tex]
Molecular mass of solute = 211.66 g/mol.
The molecular mass of the unknown has been 211.66 g/mol.
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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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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.
The Ka1 value for oxalic acid is 5.9 x10-2 , and the Ka2 value is 4.6 x 10-5 . What are the values of Kb1 and Kb2 of the oxalate ion
Answer:
2.17x10⁻¹⁰ = Kb1
1.69x10⁻¹³ = Kb2
Explanation:
Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:
C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²
C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵
Oxalate ion, C₂O₄²⁻, has as equilibriums:
C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2
Also, you can know: KaₓKb = Kw
Where Kw is 1x10⁻¹⁴
Thus:
Kw = Kb2ₓKa1
1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵
2.17x10⁻¹⁰ = Kb1And:
Kw = Kb1ₓKa2
1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²
1.69x10⁻¹³ = Kb1
That is because the inverse reaction of, for example, Ka1:
C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1
+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴
=
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1
What is the new mass/volume percent (m/v) of a KOH solution that is prepared by diluting 110 mL of a 6.0% (m/v) KOH solution to 330 mL
Answer:
The new mass/volume percent is 2.0% (m/v)
Explanation:
Dilution is a procedure by which the concentration of a solution is decreased, generally with the addition of a diluent. In other words, dilution is a process in which a concentrated solution is always started, to which a greater volume of solvent is added, causing the concentration and volume of the resulting solution to change. But the amount of solute used to prepare the initial solution remains the same.
The calculation of a dilution is made by:
Cinitial. Vinitial = Cfinal. Vfinal
where C indicates concentration and V indicates volume.
In this case:
Cinitial: 6.0% (m/v)Vinitial: 110 mLCfinal: ?Vfinal: 330 mLReplacing:
6.0% (m/v) * 110 mL= Cfinal* 330 mL
Solving:
[tex]Cfinal=\frac{ 6.0 (m/v)*110 mL}{330 mL}[/tex]
Cfinal= 2.0% (m/v)
The new mass/volume percent is 2.0% (m/v)
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
What is the systematic name for the given compound? (R)-2-bromobutane (S)-2-bromobutane (R)-2-butyl bromide (S)-2-butyl bromide
Answer:
See explanation below
Explanation:
IUPAC came up with the idea of an unambiguous system of nomenclature for organic compounds. This unambiguous system relates the structure of a compound with its name. Thus, IUPAC has established a worldwide standard for the unambiguous naming of organic compounds. Scientists all over the world can now have a uniform system of nomenclature for compounds in order to facilitate easy communication of scientific information.
The systematic names of the following compounds listed in the question are shown below;
(R)-2- butyl bromide has the systematic name (R)-2-bromobutane
(S)-2-butyl bromide has the systematic name (S)-2-bromobutane
This unified system of nomenclature avoids the confusion created by the use of different trivial names in deferent localities and by various scientific academies. This is a major advantage of the systematic nomenclature.
which vitamin is more soluble in water ? explain
Answer:
Vitamin C and B complex is the water soluble.but in question option is A abd C so, among them vitamin C is the water soluble vitamin.
Explanation:
Because it is easily soluble in water and when there is more amount of asorbic acid it has to be mixed in urine and are released out from body.
hope it helps..
Find the molality of this aqueous solution 15.0% by mass kBr (119g/mol).
Answer:
we will take a 100g sample of this solution for our convenience
so , there is 15 g kBr in this 100g solution
we know that molality is the number if moles of solute / mass of solvent in kg
we need to find the number of moles in 15g kBr
no of moles = 15/119 s
moles = 0.126 moles/ 100g
multiplying both the numerator and the denominator by 10 to get 1 kg in denominator
= 1.26 moles / 1 kg
Hence, the molality is 1.26
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Calcium carbide, CaC2, reacts with water to form calcium hydroxide and the flammable gas ethyne (acetylene) in the reaction: What mass of ethyne can be produced
Answer:
1 mole of CaC₂ will produce 26g of C₂H₂ or 64.1g of CaC₂ will produce 26g of C₂H₂
Explanation:
Hello,
To solve this question, we'll require a balanced chemical equation of reaction between calcium carbide and water.
Equation of reaction
CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂
Molar mass of calcium carbide (CaC₂) = 64.1g/mol
Molar mass of water (H₂O) = 18g/mol
Molar mass of calcium hydroxide (Ca(OH)₂) = 74g/mol
Molar mass of ethyne (C₂H₂) = 26g/mol
From the equation of reaction, 1 mole of CaC₂ will produce 1 mole of C₂H₂
1 mole of CaC₂ = mass / molar mass
Mass = 1 × 64.1
Mass = 64.1g
1 mole of C₂H₂ = mass / molar mass
Mass = 1 × 26
Mass = 26g
Therefore, 1 mole of CaC₂ will produce 26g of C₂H₂
Note: this is a hypothetical calculation since we were not given the initial mass of CaC₂ that starts the reaction
Suppose that you add 28.8 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f Kf of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.06 oC compared to pure benzene. What is the molar mass of the unknown compound
Answer:
THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.
Explanation:
First:
Calculate the change in freezing point:
Freezing point of pure benzene = 5.5°C
Change in temperature = 5.5 - 3.06 = 2.44 °C
Second:
Using the formula:
Δt = i Kf m
Let's assume i = 1
Kf = 5.12 °C/m
M = x / 0.250 kg of benzene
Then we can calculate x which is the molarity
Re-arranging the formula, we have:
m = Δt / i Kf
x / 0.250 = 2.44 / 1 * 5.12
x = 2.44 * 0.250 / 5.12
x = 0.61 / 5.12
x = 0.119 M
Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.
Molar mass = Mass / molarity
Molar mass = 28.8 g / 0.119 M
Molar mass =242.02 g/mol
Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.
In Sir Isaac Newton's time in the early 1700s, what was the general consensus among scientists on the properties of light?
Answer:
Light is composed of particles and travels in a straight line.
Explanation:
The general consensus among scientists in Sir Isaac Newton's time in the early 1700s was that light was composed of a steady stream of particles, since it was observed that light traveled in a straight line and was able to pass through a vacuum. They argued along the lines of Sir Isaac Newton that since sound travels in waves and cannot travel though a vacuum, light must consist of something other than waves, such as particles.
Also, on reflection of light from rough surfaces, the particle theory suggests that if the surface is very rough, the particles bounce away at different angles from the surface, scattering the light as is confirmed by experimental observation.
In his 1704 book Opticks, Sir Isaac Newton stated that "Light is never known to follow crooked passages nor to bend into the shadow". This idea lent support to the particle theory, which proposes that light particles must always travel in straight lines. If the particles encounter the edge of a barrier, then they will cast a shadow because the particles not blocked by the barrier continue on in a straight line and cannot spread out behind the edge. This was observed in eclipses as well as formation of shadow of objects.
Answer:
Light is composed of particles and travels in a straight line.
Explanation:
PF The majority of scientists in the early 1700s agreed that light must be particle-like, since it was apparent that light traveled in a straight line and was able to pass through a vacuum. Their logic was that since sound travels in waves and can't travel though a vacuum, light must consist of something other than waves, such as particles.
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.
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
what is the mass of 2.10 x 10^22 formula units of naoh (molar mass equals 40.0 g/mol)
1.39 g
the mass of 2.10×10^23
molar mass 40.0 g/mol
The mass of 2.10 x 10²² formula units of NaOH is 1.39 grams.
Mass is defined as a quantitative measure of inertia, a basic feature of all matter.
Mass is also defined as a dimensionless quantity that represents the amount of substance contained in a particle or item.
It can be called as the quantity of substance in any item or body.
The SI unit of mass can be grams or kilograms.
It is a scalar quantity.
Total number of molecule = 2.10 x 10²²
Molar mass = 40.0 g/mole
Number of molecules = mass / malar mass x 6.023 x 10²³
So, Mass = Number of molecule x molar mass / 6.023 x 10²³
Mass = 2.10 x 10²² x 40.0 / 6.023 x 10²³
Mass = 1.39 grams
Thus, the mass of 2.10 x 10^22 formula units of NaOH is 1.39 grams.
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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
Strontium crystallizes in a face-centered cubic unit cell having an edge length of 77.43 pm. What is the atomic radius of strontium (in picometers) based on this structure
Answer:
Atomic radius of Strontium is 27.38pm
Explanation:
In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:
a² + a² = b² = (4r)²
2a² = 16r²
a = √8 r
As edge length of Strontium is 77.43pm:
77.43pm / √8 = r
27.38pm = r
Atomic radius of Strontium is 27.38pm8. Exactly 169.5 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal?
Answer:
THE SPECIFIC HEAT OF THE METAL IS 0.4843 J/G °C
Explanation:
Heat involved in the reaction is 169.5 J
mass of the metal = 10 g
Change in temperature = 60 °C - 25 °C = 35 °C
Specific heat of the metal = unknown
Specific heat of a metal or substance is the amount of heat per unit mass required to raise the temperature by one degree Celsius.
Using the formula for heat of a reaction, which is:
Heat = mass * specific heat * change in temperature
Heat = m C ΔT
Re-arranging the formula by making C the subject of the formula, we get:
C = Heat / m ΔT
C = 169.5 J / 10 g * 35 C
C = 169.5 J / 350 g °C
C = 0.4843 J/g°C
So therefore, the specific heat of the metal is 0.4843 J/ g°C
an extra strength antacid tablet contains 750 mg of active ingredient, caco3. if it takes 22.25 ml of hcl to neutralize the tablet, how strong is the acid
Answer:
The HCl is very strong since its pH is equal to 0.17.
Explanation:
The reaction between CaCO₃ and HCl is:
CaCO₃(s) + 2HCl(aq) ⇄ CaCl₂(aq) + CO₂(g) + H₂O(l) (1)
The number of moles of CaCO₃ is:
[tex] n_{CaCO_{3}} = \frac{m}{M} [/tex]
Where:
m: is the mass = 0.750 g
M: is the molar mass = 100.0869 g/mol
[tex] n_{CaCO_{3}} = \frac{0.750 g}{100.0869 g/mol} = 7.49 \cdot 10^{-3} moles [/tex]
From the reaction (1) we have that 1 mol of CaCO₃ reacts with 2 moles of HCl, so the number of moles of HCl is:
[tex] n_{HCl} = 2*7.49 \cdot 10^{-3} moles = 0.015 moles [/tex]
Now, with the number of moles of HCl we can find its concentration:
[tex] C = \frac{n}{V} = \frac{0.015 moles}{22.25 \cdot 10^{-3} L} = 0.67 M [/tex]
Finally, the pH of the acid is:
[tex] pH = -log([H^{+}]) = -log(0.67) = 0.17 [/tex]
The pH obtained is very low, so the HCl is very strong.
Therefore, the HCl is very strong since its pH is equal to 0.17.
I hope it helps you!
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.
In principle, the equilibrium in the dehydration of an alcohol could be shifted to the right be removal of water. Why is this tactic not a good option for the dehydration of 4-methyl-2-pentanol and cyclohexanol
Answer:
See explanation
Explanation:
In this case, we have to remember that if we want to remove water from the reaction vessel we have to heat the vessel. So, we can convert the liquid water into gas water and we can remove it from the vessel. In this case, the products of dehydration for both molecules are (E)-4-methylpent-2-ene and cyclohexene with boiling points of 59.2 ºC and 89 ºC respectively. The boiling point of water is 100 ºC, therefore if we heat the vessel the products and water would leave the system, and the products would be lost.
See figure 1
I hope it helps!
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
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