Answer:
A. Neutral salts. (7, 2)
B. Acidic salts. (4, 6)
C. Basic salts. (1, 3, 5)
Explanation:
We must know where, do the ions come from. If they come from a weak acid or base, they can make hydrolysis in water, so OH⁻ and H⁺ are given to medium.
1. LiF → Li⁺ + F⁻
F⁻ + H₂O ⇄ HF + OH⁻
F⁻ can make the hydrolysis, and it gives OH⁻. Salt is basic.
2. SrBr₂ → Sr²⁺ + 2Br⁻
Both are weak and they can not hydrolyse. This salt is neutral.
3. NH₄CN → NH₄⁺ + CN⁻
Both ions are strong, so they can make the hydrolysis. The thing is, while the ammonium gives protons, the cyanide give hydroxides. To determine how's the salt, we need to compare the Ka and Kb.
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka = 5.7×10⁻¹⁰
CN⁻ + H₂O ⇄ HCN + OH⁻ Kb = 1.61×10⁻⁵
As Kb > Ka, pH is basic.
If Ka > Kb, pH would be acidic.
4. NH₄Br → NH₄ + Br⁻
Br⁻ does not hydrolize. The ammonium cation, reacts in water to give protons to medium that's why the salt will be acidic.
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
5. KCN → K⁺ + CN⁻
K⁺ does not hydrolize. The cyanide anion, reacts in water to give hydroxides to medium that's why the salt will be basic.
CN⁻ + H₂O ⇄ HCN + OH⁻ Kb
6. NH₄ClO₄ → NH₄⁺ + ClO₄⁻
ClO₄⁻ comes from the perchlroric acid (a strong acid). It does not hydrolyze
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
Ammonium gives H⁺ to medium so the salt is acidic.
7. LiNO₃ → Li⁺ + NO₃⁻
Both ions does not make hydrolysis. They come from a strong base and a strong acid, so they are the conjugate weak acid and base, respectively.
The salt in this case, will be neutral.
A mixture containing only FeCl3 and AlClz weighs 5.95 g . The chlorides are converted to the hydrous oxides and ignited to Fe2O3 and Al2O3 . The oxide mixture weighs 2.62 g . Calculate the percent Fe and Al in the original mixture .
Answer:
The answer is "Al= 9.8% and Fe=18.0%"
Explanation:
Given:
The weight of [tex]FeCl_3\ and \ ALCl_3[/tex] = 5.95g
[tex]gFeCl_3=gFe (\frac{Mw\ FeCL_3}{\text{atomic weight of Fe}})\\\\gAlCl_3=gAl (\frac{Mw\ AlCL_3}{\text{atomic weight of Al}})\\\\[/tex]
[tex]\to a = FeCl_3+AlCl_3\\\\\to a=x+y \\\\ \to a= 5.95[/tex]
[tex]\to a =x \ gFe (\frac{Mw\ FeCL_3}{\text{atomic weight of Fe}})+ y \ gAl (\frac{Mw\ AlCL_3}{\text{atomic weight of Al}})\\\\[/tex]
[tex]\to x (\frac{162.2}{55.85})+ y (\frac{133.34}{26.98})= 5.95\\\\\to 2.90x+4.94y=5.95\\\\\ similarly \ for \ oxidies:\\\\\to 143x+1.89y=2.62\\\\\to x= 1.07 \ \ \ and \ \ y= 0.58\\\\\to \ Al \% = \frac{0.58}{5.95} \times 100= \bold{9.8} \%\\\\\to \ Fe \% = \frac{1.07}{5.95} \times 100= \bold{18.0} \%[/tex]
The mass of the compound has been given as the mass of each element in the compound. The percent Fe in the mixture is 18%, and the percent Al in the mixture is 9.8%.
What is the percent composition?The percent composition has been given as the mass of the element in the compound. The percent of iron and aluminum in their chlorides can be given as:
[tex]\rm Fe=Fe\;\times\;\dfrac{Mwt\;FeCl_3}{Mwt\;Fe}[/tex]
[tex]\rm Al=Al\;\times\;\dfrac{Mwt\;AlCl_3}{Mwt\;Al}[/tex]
The total mass of the compounds has been 5.95 grams.
Thus,
[tex]5.95=\rm FeCl_3+AlCl_3[/tex]
The mass of Fe and Al will be x and y of the mass in the compounds. Thus,
[tex]5.95=\rm x\;Fe\;\times\;\dfrac{Mwt\;FeCl_3}{Mwt\;Fe}\;+\;y\;Al\;\times\; \dfrac{Mwt\;AlCl_3}{Mwt\;Al}[/tex]
The oxides of the chemical has the sum of mass of 2.62 grams.
The mass of oxides can be given as:
[tex]2.62=\rm x\;Fe\;\times\;\dfrac{Mwt\;Fe2O_3}{Mwt\;Fe}\;+\;y\;Al\;\times\; \dfrac{Mwt\;Al_2O_3}{Mwt\;Al}[/tex]
Substituting the values of mass of Al, aluminum chloride, oxide, and Fe and its compounds.
[tex]\rm 2.90x+4.94y=5.95\\143x+1.89y=2.62[/tex]
Solving the equation, x = 1.07, and y = 0.58
The percent mass of the compounds has been given as the ratio of mass with compound mass.
Thus, the percent mass of Fe has been:
[tex]\rm Fe=\dfrac{1.07}{5.95}\;\times\;100\\ Fe=18\;\%[/tex]
The percent mass of Al has been:
[tex]\rm Al=\dfrac{0.58}{5.95}\;\times\;100\\ Al=9.8\;\%[/tex]
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10.
17.0cm
23.0cm
4,00cm
A 38.6 kg marble slab is shown above. What is its density? Give your
answer to the nearest tenth.
g/cm3
Enter the answer
Check it
Answer:
Density, [tex]\rho=24.68\ g/cm^3[/tex]
Explanation:
Mass of a marble slab is 38.6 kg 38600 grams
The dimensions of the marble is 17 cm×23 cm×4 cm
We need to find its density. Mass per unit volume equals density. So,
[tex]\rho=\dfrac{m}{V}\\\\\rho=\dfrac{m}{lbh}\\\\\rho=\dfrac{38600\ g}{(17\times 23\times 4)\ cm^3}\\\\\rho=24.68\ g/cm^3[/tex]
So, the density of the marble slab is [tex]24.68\ g/cm^3[/tex]
Peripherals are used to?
Answer:
Peripheral device, also known as peripheral, computer peripheral, input-output device, or input/output device, any of various devices (including sensors) used to enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator or, in some cases.
Explanation:
Hope it helps
Answer: Input and output data
Explanation:
Plato!!!!!!!!!
A rigid tank contains 1.80 moles of nitrogen, which can be treated as an ideal gas, at a pressure of 25.5 atm. While the tank and gas maintain a constant volume and temperature, a number of moles are removed from the tank, reducing the pressure to 5.70 atm. How many moles are removed
Answer:
1.4 moles.
Explanation:
The following data were obtained from the question:
Initial mole (n1) = 1.8 moles
Initial pressure (P1) = 25.5 atm
Final pressure (P2) = 5.7 atm
Number of mole removed =?
Next, we shall obtain an expression relating pressure and number of mole together.
This is illustrated below:
From the ideal gas equation:
PV = nRT
Divide both side by V
P = nRT /V
Divide both side by n
P/n = RT/V
But volume (V) and temperature (T) are constant.
P/n = constant
P1/n1 = P2/n2
P1 is initial pressure.
P2 is final pressure.
n1 is the initial mole.
n2 is the final mole.
Next, we shall determine the final mole in tank as follow:
Initial mole (n1) = 1.8 moles
Initial pressure (P1) = 25.5 atm
Final pressure (P2) = 5.7 atm
Final mole (n2) =.?
P1/n1 = P2/n2
25.5/1.8 = 5.7/n2
Cross multiply
25.5 x n2 = 1.8 x 5.7
Divide both side by 25.5
n2 = (1.8 x 5.7) /25.5
n2 = 0.40 mole.
Therefore, the final mole in the tank is 0.40 mole.
Finally, we shall determine the number of mole that was removed as follow:
Initial mole (n1) = 1.8 moles
Final mole (n2) = 0.4 mole
Number of mole removed =?
The number of mole removed from the tank can be obtained by finding the difference between the initial mole and final mole as illustrated below:
Number of mole removed = initial mole – final mole
Number of mole removed = n1 – n2
Number of mole removed = 1.8 – 0.4
Number of mole removed = 1.4 moles
Therefore, 1.4 moles were removed from the tank.
0.200 grams of HCl is dissolved in 0.801 grams water. The density of the solution formed is 1.10 g/mL. What is the molarity of the solution
Answer:
[tex]M=6.03M[/tex]
Explanation:
Hello,
In this case, since the molarity is computed by:
[tex]M=\frac{n_{solute}}{V_{solution}}[/tex]
Whereas the solute is the hydrochloric acid, we compute the corresponding moles with its molar mass (36.45 g/mol):
[tex]n_{solute}=0.200gHCl*\frac{1molHCl}{36.45gHCl} =0.00549molHCl[/tex]
Next, since the solution contains both HCl and water, we compute the volume in liters by using its density:
[tex]V_{solution}=(0.200+0.801)g*\frac{1mL}{1.10g} *\frac{1L}{1000mL} =9.1x10^{-4}L[/tex]
Therefore, the molarity turns out:
[tex]M=\frac{0.00549mol}{9.1x10^{-4}L}\\ \\M=6.03M[/tex]
Regards.
Which measurement is best supported in units of microliters ?
The mass of an atom of uranium
The volume of a water droplet in a cloud
The thickness of a strand of hair
The volume of the Atlantic Ocean
Answer:the volume of a water droplet in a cloud
Explanation:
Answer:
The volume of a water droplet in a cloud
Explanation:
just took the test
A student is designing an experiment about the factors that affect math
grades. Which statement best represents a possible hypothesis for this
experiment?
O A. I think practicing math problems is the most important factor in a
student's math grade.
OB. If students spend at least 1 hour per night studying math, then
they will get a grade of 85 or higher.
C. Students who study more get higher math grades.
O D. Steve studied math for 1 hour every night and got a grade of 87.
Answer:
B. If students spend at least 1 hour per night studying math, then they will get a grade of 85 or higher.
Explanation:
A hypothesis is defined as a tentative or predictions or an educated guess of scientific questions. A hypothesis is always done before performing an experiment.
The correct hypothesis for the given experiment will be "If students spend at least 1 hour per night studying math, then they will get a grade of 85 or higher" because it has an if-then statement which is a conditional statement where statement after "if represents hypothesis" and "then represents conclusion".
Hence, the correct answer is "B. If students spend at least 1 hour per night studying math, then they will get a grade of 85 or higher."
find the value of y in the equation Зу – 20 = 7.
[tex]3y-20=7\implies y=\frac{20+7}{3}=9[/tex].
Hope this helps.
y= 9
Explanation:
=> 3y - 20 = 7
=> 3y = 7+20
=> 3y = 27
=> y = 27/3
=> y = 9
HOPE OT HELPS. ◉‿◉
Which of the following molecules has a characteristic broad stretch at 3300 cm-1?
A) (CH3)2CHCH2OH
B) (CH3)3CH
C) (CH3)2CHCCCH3
D) (CH3)2CHCH=CH2
E) (CH3)2CHCO2CH3
Answer:
The answer is "Option A"
Explanation:
At 3300 cm-1, the wide region is equal to OH. It is a possible group of alcoholic features that includes drugs. In the given choices option a is correct that's the structure can be defined in attachment file please find it, and the wrong choice can be defined as follows:
In choice B, It is wrong because it doesn't include OH. In choice C, it uses the triple bond, that's why it is wrong. In choice D, it uses the two bonds, that's why it is wrong. In choice E, it uses the characteristic bond, that's why it is wrong.How much work does a gas do when it expands against a constant pressure of 0.600 atm from a volume of 50.00 mL to a volume of 440.00 mL?
Answer:
23.71J is the work that the gas do.
Explanation:
The work that a gas do under isobaric conditions follows the formula:
W = P*ΔV
Where W is work in atmL, P is the pressure and ΔV is final volume -Initial volume In Liters
Replacing with the values of the problem:
W = P*ΔV
W = 0.600atm*(0.44000L - 0.0500L)
W = 0.234atmL
In Joules (1atmL = 101.325J):
0.234atmL × (101.325J / 1 atmL) =
23.71J is the work that the gas do.
the distance between atomes is sometimes given in picometers,where 1pm is equivalent to 1×10^12m if the distance between the carbon atomes in diamond is 2.81×10^8,what is the distance in picometers?
Answer:
Distance between the carbon atom = 491 pm
Explanation:
Given:
1 pm = 1 × 10⁻¹² m
Distance between the carbon atom = 2.81 × 10⁻⁸ cm
Find:
Distance in picometers
Computation:
Distance between the carbon atom = 2.81 × 10⁻⁸ cm = 491 X 10⁻¹² m
Distance between the carbon atom = 491 pm
In the measurement 0.502 L, which digit is the estimated digit? A. 5 B. 3 C. The 0 to the left of the decimal point D. The 0 immediately to the left of the 3
Answer:
no c
Explanation:
Calculate the mass percent of HOCH 2CH 2OH in a solution made by dissolving 3.2 g of HOCH 2CH 2OH in 43.5g of water.
Answer:
[tex]\%m/m=6.85\%[/tex]
Explanation:
Hello,
In this case, we are asked to compute the by mass percent for the given 3.2 g of ethylene glycol in 43.5 g of water. In such a way, since the by mass percent is computed as follows:
[tex]\%m/m=\frac{m_{solute}}{m_{solute}+m_{solvent}} *100\%[/tex]
Whereas the solute is the ethylene glycol and the solvent the water, therefore we obtain:
[tex]\%m/m=\frac{3.2g}{3.2g+43.5g} *100\%\\\\\%m/m=6.85\%[/tex]
Best regards.
Write the condensed nd structural formulas as well as the names for all isomers of C3H5Cl3.
Answer:
1) 1,1,1-trichloropropane
2) 1,1,2-trichloropropane
3) 1,2,2-trichloropropane
4) 1,2,3-trichloropropane
Explanation:
For this question, we must remember that isomers are molecules that have the same formula but different structures. For the formula [tex]C_3H_5Cl_3[/tex] we can draw a linear chain of three carbons and change the position of the chlorine atoms in the carbon chain.
With this in mind, if we put all the chlorine atoms on the same carbon we will get 1,1,1-trichloropropane. If we change an atom from chlorine to carbon 2 we will obtain 1,1,2-trichloropropane. If we move another chlorine atom to carbon two we will get 1,2,2-trichloropropane. Finally, if we put a chlorine atom in each carbon we will obtain 1,2,3-trichloropropane.
See figure one for further explanations
I hope it helps!
Students in a science class placed ice cubes in a cup. They were studying variables that affected how long it takes the ice to melt. Select the variable that
would most likely NOT affect the time it takes the ice to melt.
O Size of cup
O Size of ice cube
O Number of students
O Temperature of the room
Answer:
Number of students-this has nothing to do with the question, its called a distractor.
The variable that would most likely not affect the time it takes the ice to melt is the Number of students. The correct option is C.
What are the variables in the experiments?Variables are the different substances or objects that participate in the experiment directly or indirectly. They are substances that together form the experiment. These variables impact the result of the experiment.
There are two types of variables. They are Dependent and independent variables. Dependent variables can be controlled in the experiment, but independent variables can't be controlled.
Students are performing the experiment, so they cannot be the variables because their presence or absence would be to impact the experiment.
Thus, the correct option is C. Number of students.
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HCl(aq) + NaOH(aq) ––––> NaCl(aq) + H2O(l) What volume of 0.631 M HCl is required to react with 15.8 mL of 0.321 M NaOH?
Answer:
The correct answer is 8.04 mL
Explanation:
Given the neutralization reaction:
HCl(aq) + NaOH(aq) ––––> NaCl(aq) + H₂O(l)
1 mol of HCl reacts with 1 mol of NaOH.
The number of moles of NaOH there is in 15.8 mL is calculated as follows:
0.321 mol/L x 1 L/1000 mL x 15.8 mL = 5.07 x 10⁻³ mol NaOH
Thus, we need 5.07 x 10⁻³ mol of HCl to react with 5.07 x 10⁻³ mol NaOH. We have a 0.631 M HCl solution. We calculate the volume of HCl we need by considering that 1 mol NaOH reacts with 1 mol HCl and that there are 0.631 moles of HCl in 1 liter of solution (1000 mL):
5.07 x 10⁻³ mol NaOH x 1 mol HCl/1 mol NaOH x 1000 mL/0.631 mol HCl = 8.04 mL
You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring? \
Answer:
You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring?
If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.
Sample Response: If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.
What did you discuss in your response? Check all that apply.
the production of an odor
a change in energy
a change in color
the formation of a solid
the formation of new substances
a change in properties and identities
A chemical change may result in the following;
Evolution of gasChange in temperature of the reaction mixtureAppearance of a solidChange in colorA Physical change may result in the following;
Change in appearanceChange in sizeChange in shapeChange in textureA chemical change leads to the formation of a new substance. This implies that the composition of the substance has being changed.
A physical change does not lead to a change in the nature of the substance. However, the appearance, shape, texture or size of the substance may change.
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Which of the following is included in nuclide symbols, but is not strictly necessary for the identification of the nuclide?
a. mass number
b. atomic number
c. isotope number
d. none of the above
Answer:
c. isotope number
Explanation:
Mass Number is the sum total of mass of protons and neutrons present in the nucleus of an atom. Generally they are being used in distinguishing isotopes. E.g Carbon - 12, Carbon - 13
Atomic Number is the number of protons. Every single element has it's unique atomic number and can be used in identification purpose. E.g Carbon - 6, Hydrogen - 1.
The correct option is option C. This is the symbol that is not necessary for the identification of a nuclide.
Answer: B, atomic number
Which has the greatest mass?a. one atom of carbon, b. one atom of hydrogenc. one atom of lithium
Answer:
one atom of carbon
Explanation:
The relative atomic mass of elements can be used to determine their relative masses. If we look at all the options, we will notice that carbon has a relative atomic mass of 12, hydrogen has a relative atomic mass of 1 and lithium has a relative atomic mass of 7
We can now see that carbon has the greatest relative atomic mass among the options provided in the question.
1. Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) ? 2Al2O3(s)
Using the thermodynamic data provided below, calculate S° for this reaction.
S°(J/K.mol)
Al(s) 28.3
O2(g) 205.0
Al2O3(s) 50.99
2. Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) ? Al2O3(s)
Calculate G° for this reaction, given that ?G°f of aluminum oxide is –1576.4 kJ/mol.
Answer:
Al(s) 28.3
Explanation:
Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.4Al(s) + 3O2(g) ? Al2O3(s)
AnswerAluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) ? 2Al2O3(s)
Using the thermodynamic data provided below, calculate S° for this reaction.
S°(J/K.mol)
Al(s) 28.3
O2(g) 205.0
Al2O3(s) 50.99
2. Aluminum forms a layer of aluminum oxide when exposed to air which protects the bulk metal from further corrosion.
4Al(s) + 3O2(g) ? Al2O3(s)
Calculate G° for this reaction, given that ?G°f of aluminum oxide is –1576.4 kJ/mol.
Answer:
Explanation:
Explanation:
Monomer liquid and polymer powder nail enhancement are service
Answer:
Monomer liquid and polymer powder nail enhancement are lucrative service
3. How many significant figures are in the number 805000? *
Answer:
3
Explanation:
Three significant figures
Select the conjugate acid-base pair(s). a) HI, I b) HCHO2, SO4^2- c) CO3^2-, HCI d) PO4^3-, HPO4^2-
Answer:
d) PO4^3-, HPO4^2-
Explanation:
Basically, an acid and a base which differs only by the presence or absence of proton (hydrogen ion) are called a conjugate acid-base pair.
a) HI, I
This is incorrect. For the acid, HI the conjugate base is I⁻ ion.
b) HCHO2, SO4^2-
This is incorrect, there's no relationship between both entities.
c) CO3^2-, HCI
This is incorrect, there's no relationship between both entities.
d) PO4^3-, HPO4^2-
This is correct. The difference between both entities is the Hydrogen ion. This is the conjugate acid-base pair
Acetyl chloride undergoes nucleophilic substitution at a faster rate than methyl acetate because:_________
A) the ester is more sterically hindered than the acid chloride.
B) the acid chloride is more sterically hindered than the ester.
C) the methoxide is a better leaving group than chloride.
D) esters hydrolyze faster than acid chlorides.
E) chloride is a better leaving group than methoxide.
The value of the equilibrium constant for a reaction is 2.65 x 10-6 at 35° Calculate the value of LaTeX: \DeltaΔG°rxn.
Answer:
The answer is "33.95 [tex]\bold{ \frac{kj}{mol}}\\[/tex]".
Explanation:
Formula:
[tex]\bigtriangleup G_0= -R \times T l_n \times K_{eq}\\[/tex]
where
[tex]K_{eq} = \text{equilibrium constant}\\[/tex]
Given value:
[tex]T =35^{\circ} C\\[/tex]
convert temperature celsius (°C) to Kelvin (K):
[tex]= (273+45) \ kelvin \\\\= 318 \ Kelvin \\\\= 318 \ K[/tex]
[tex]R = 8.314 \ \ \frac{J}{ mol \cdot K}[/tex]
[tex]\bigtriangleup G_0= -(8.314 ) \times 31.8 \times l_n (2.65\times 10^{-6})\\[/tex]
[tex]=-(8.314 ) \times 31.8T l_n \times (2.65\times 10^{-6})\\\\[/tex]
After solving the value it will give:
= 33.95 [tex]\bold{ \frac{kj}{mol}}\\[/tex]
Calculate the pH of a 0.10 M HCN solution that is 0.0070% ionized.
A) 1.00
B) 0.00070
C) 3.15
D) 5.15
E) 7.00
Answer:
D) 5.15
Explanation:
Step 1: Write the equation for the dissociation of HCN
HCN(aq) ⇄ H⁺(aq) + CN⁻(aq)
Step 2: Calculate [H⁺] at equilibrium
The percent of ionization (α%) is equal to the concentration of one ion at the equilibrium divided by the initial concentration of the acid times 100%.
α% = [H⁺]eq / [HCN]₀ × 100%
[H⁺]eq = α%/100% × [HCN]₀
[H⁺]eq = 0.0070%/100% × 0.10 M
[H⁺]eq = 7.0 × 10⁻⁶ M
Step 3: Calculate the pH
pH = -log [H⁺] = -log 7.0 × 10⁻⁶ = 5.15
The pH of the 0.10 M HCN solution that is 0.0070% ionized is 5.15 and the correct option is option D.
pH is a measure of the acidity or alkalinity of a solution. It is a logarithmic scale that indicates the concentration of hydrogen ions (H+) in the solution.
The pH scale ranges from 0 to 14, where a pH of 7 is considered neutral, pH values below 7 indicate acidity, and pH values above 7 indicate alkalinity.
The pH of a solution can be calculated using the formula:
pH = -log[H+]
Where [H+] represents the concentration of hydrogen ions in moles per liter.
Since HCN is a weak acid and only 0.0070% of it is ionized, assuming that the concentration of H+ ions is equal to 0.0070% of 0.10 M HCN.
0.0070% of 0.10 M HCN = (0.0070/100) × 0.10
= 0.000007 M
pH = -log(0.000007)
= 5.15
Thus, the ideal selection is option D.
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Dinitrogen tetroxide and hydrazine (N2H4) undergo a redox reaction in which nitrogen and water are formed as products. What mass of nitrogen could be produced when 50.0 g of dinitrogen tetroxide and 45.0 g of hydrazine are combined?
Answer:
The mass of nitrogen molecule [tex]N_2[/tex] = 45.65 g
Explanation:
The equation for the redox reaction can be represented as follows:
[tex]\mathtt{2N_2H_4 +N_2O_4 \ \to \ 3N_2 + 4H_2O}[/tex]
We know that:
numbers of moles = mass/molar mass
For [tex]\mathtt{N_2O_4}[/tex] :
number of moles = 50g/92 g/mol
number of moles = 0.5435 mol
For [tex]\mathtt{N_2H_4}[/tex] :
number of moles = 45 g/ 32 g/mol
number of moles = 1.40625 mol
From the above equation;
number of moles of [tex]\mathtt{N_2O_4}[/tex] needed = 1/2 moles of [tex]\mathtt{N_2H_4}[/tex] = 1/2 × 1.40625 mol
= 0.703125 mol
The amount of [tex]\mathtt{N_2O_4}[/tex] present = 0.5435 moles which is less than the needed. As such [tex]\mathtt{N_2O_4}[/tex] is the limiting reagent
The number of moles of nitrogen molecule [tex]N_2[/tex] produced = 3 × ([tex]\mathtt{N_2O_4}[/tex])
= 3 × 0.5435
= 1.6305 mol
The mass of nitrogen molecule [tex]N_2[/tex] = number of moles of [tex]N_2[/tex] × molar mass of [tex]N_2[/tex]
The mass of nitrogen molecule [tex]N_2[/tex] = 1.6305 mol × 28 g/mol
The mass of nitrogen molecule [tex]N_2[/tex] = 45.654 g
The mass of nitrogen molecule [tex]N_2[/tex] = 45.65 g
Predict the reactivity of silicon in water relative to that of sodium, magnesium, and aluminium. Explain your answer. How does the reactivity of the halogens vary within its own group from top to bottom?
Answer:
See explanation
Explanation:
The reactivity of metals has a lot to do with their position in the electrochemical series. However, it is also known that metallic character decreases across the period. This implies that as we move from left to right along the periodic table. Sodium, magnesium, aluminum and silicon continues to decrease in metallic character. As a matter of fact, silicon is a metalloid and not a pure metal.
Sodium reacts with cold water to give a vigorous reaction,magnesium and aluminium reacts with steam at red heat.
Silicon does not react with water, even as steam, under normal conditions.
Reactivity can be given as the ability of the atom to lose or gain electrons. The reactivity can be silicon is least as compared to sodium and other metals in water.
What is the trend of reactivity in the periodic table?The periodic table has the arrangement of the elements in groups and periods in the table.
On moving from left to right in the periodic table, the number of electrons in the same shell increase, thereby making the loss of electrons difficult. Thus, on moving from left to right in the periodic table, the metal reactivity decreases.
Hence, silicon present in the right most of the periodic table has the lower reactivity as compared to the sodium, magnesium, and aluminum on the left side of the periodic table.
In the periodic table, on moving from top to bottom, the number of shells increases, decreasing the force of attraction to the outermost electron. Thus, the metal reactivity increases down the group.
Learn more about reactivity, here:
https://brainly.com/question/1598581
Determine the pH of the resulting solution if 25 mL of 0.400 M strychnine (C21H22N2O2) is added to 50 mL of 0.200 M HCl? Assume that the volumes of the solutions are additive. For strychnine at the temperature of the experiment, Kb = 1.8 × 10-6.
Answer:
pH = 4.56
Explanation:
The strychnine reacts with HCl as follows:
C₂₁H₂₂N₂O₂ + HCl ⇄ C₂₁H₂₂N₂O₂H⁺ + Cl⁻
For strychnine buffer:
pOH = 5.74 + log [C₂₁H₂₂N₂O₂H⁺] / [C₂₁H₂₂N₂O₂]
Initial moles of C₂₁H₂₂N₂O₂ are:
0.025L * (0.400 mol / L) = 0.01 moles C₂₁H₂₂N₂O₂
And of HCl are:
0.05L * (0.200 mol / L) = 0.01 moles HCl
That means after the reaction, you will have just 0.01 moles of C₂₁H₂₂N₂O₂H⁺ in 50mL + 25mL = 0.075L. And molarity is:
[C₂₁H₂₂N₂O₂H⁺] = 0.01 mol / 0.075L = 0.1333M
This conjugate acid, is in equilibrium with water as follows:
C₂₁H₂₂N₂O₂H⁺(aq) + H₂O(l) ⇄ C₂₁H₂₂N₂O₂ + H₃O⁺
Where Ka = Kw / Kb = 1x10⁻¹⁴ / 1.8x10⁻⁶ = 5.556x10⁻⁹
Ka is defined as:
Ka = 5.556x10⁻⁹ = [C₂₁H₂₂N₂O₂] [H₃O⁺] / [C₂₁H₂₂N₂O₂H⁺]
In equilibrium, concentrations are:
C₂₁H₂₂N₂O₂ = X
H₃O⁺ = X
C₂₁H₂₂N₂O₂H⁺ = 0.1333M - X
Replacing in Ka expression:
5.556x10⁻⁹ = [X] [X] / [0.1333M - X]
7.39x10⁻¹⁰ - 5.556x10⁻⁹X = X²
7.39x10⁻¹⁰ - 5.556x10⁻⁹X - X² = 0
Solving for X:
X = - 2.72x10⁻⁵M → False solution. There is no negative concentrations
X = 2.72x10⁻⁵M → Right solution.
As H₃O⁺ = X
H₃O⁺ = 2.72x10⁻⁵M
And pH = -log H₃O⁺
pH = 4.56Calculate the solubility of PbF2 in water at . You'll find data in the ALEKS Data tab. Round your answer to significant digits.
Answer:
0.5 g/L.
Explanation:
Hello,
In this case, for this solubility problem, we can write for the lead (II) fluoride:
[tex]PbF_2(s)\rightleftharpoons Pb^{2+}(aq)+2F^-(aq)[/tex]
And the equilibrium expression is:
[tex]Ksp=[Pb^{2+}][F^-]^2[/tex]
Whereas Ksp of lead (II) fluoride is 3.3x10⁻⁸. In such a way, we can write the equilibrium expression in terms of the molar solubility [tex]x[/tex] as follows:
[tex]Ksp=(x)(2x)^2=3.3x10^{-8}[/tex]
Hence, solving for [tex]x[/tex] we find:
[tex]x=\sqrt[3]{\frac{3.3x10^{-8}}{4} }\\\\x=2.02x10^{-3}M[/tex]
Moreover, since the molar mass of lead (II) fluoride is 245.2 g/mol, the solubility turns out:
[tex]2.02x10^{-3}\frac{molPbF_2}{L}*\frac{245.2gPbF_2}{1molPbF_2}\\ \\0.5\frac{g}{L}[/tex]
Best regards.