Answer:
No
Explanation:A single property is insufficient for identifying a substance
What is the percent yield of the reaction below if 84.0 grams of Al2O3(s) is recovered from a reaction whose theoretical yield of Al2O3(s) is 104 grams?
4 Al(s) + 3 O2(g) → 2 Al2O3(s)
Answer:
80.8%
Explanation:
Let's consider the following balanced equation.
4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)
The mass obtained of Al₂O₃ (experimental yield) is 84.0 g. The theoretical yield of Al₂O₃ is 104 g. We can calculate the percent yield of Al₂O₃ using the following expression.
%yield = (experimental yield / theoretical yield) × 100%
%yield = (84.0 g / 104 g) × 100% = 80.8%
Answer:
Percent Yield = 80.8%
Explanation:
We can find the percent yield of a reaction using the equation:
Percent yield = Actual yield (g) / Theoretical Yield (g) * 100
Where Actual yield is the amount of product produced (84.0g)
And theoretical yield is the mass produced assuming a 100% of product (104.0g)
Replacing the computed values:
Percent yield = 84.0g / 104.0g * 100
Percent Yield = 80.8%
The length of a covalent bond depends upon the size of the atoms and the bond order.
a. True
b. False
Answer:
True
Explanation:
The length of covalent bond depends upon the size of atoms and the bond order.
The concentration ratio of conjugate acid to conjugate base for a 20 mM solution at pH 7.0 of an amino acid is 20:1.
Required:
a. What is the pK of the side chain?
b. What amino acid might this be?
Answer:
a. 8.3= pKa of the aminoacid
b. Cysteine
Explanation:
The pH of an acid can be obtained using the H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is the pH of the buffer = 7.0
pKa is the pka of the conjugate acid = ?
[A-] / [HA] is the ratio between conjugate base and conjugate acid. As the ratio of conjugate acid to conjugate base = 20:1, the [A-] / [HA] = 1/20
Replacing:
7 = pKa + log 1/20
7 = pKa - 1.30
7+1.30 = 8.3 = pKa of the aminoacid
The only aminoacid with a side chain with pKa = 8.3 is:
Cysteine. Allowing its identification.
How many atoms are in 5.70 x 10^32 mol of Rn?
There are 3.43 × [tex]10^{56}[/tex] atom will be present in 5.70 x [tex]10^{32}[/tex] mol of Rn.
What is atom?The basic number of matter that may be broken even without producing electrically charged molecules is the atom.
Calculation of atom:
It is given that number of mol = 5.70 x [tex]10^{32}[/tex] mol.
Then, the number of atom = 5.70 x [tex]10^{32}[/tex] mol × 6.02 × [tex]10^{23}[/tex].= 3.43 × [tex]10^{56}[/tex] atom.
Therefore, there are 3.43 × [tex]10^{56}[/tex] atom will be present in 5.70 x [tex]10^{32}[/tex] mol of Rn.
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Nitrogen and hydrogen react to form ammonia, like this:N2(g)+3H2(g)→2NH3(g)Use this chemical equation to answer the questions below.Suppose 135, mmol of N₂ and 405, mmol of H₂ are added to an empty flask, How much N₂ will be in the flask at equilibrium? a. Noneb. Some, but less than 135, mmol.c. 135,mmold. More than 135, mmol.Suppose 235, mmol of NH₃ are added to an empty flask, How much N₂ will be in the flask at equilibrium? a. Noneb. Some, but less than 118, mmol.c. 118,mmold. More than 118, mmol.
Answer:
Option A is correct, there will be no N2 left in the flask
Explanation:
Step 1 : Data given
Number of moles of N2 = 135 mmol = 0.135 mol
Number of moles of H2 = 405 mmol = 0.405 mol
Step 2: The reaction
N2(g)+3H2(g)→2NH3(g)
Step 3:
For 1 mol N2 we need 3 moles H2 to produce 2 moles NH3
Both will completely react. There is no limiting reactant.
There will be produce 0.270 moles NH3.
Option A is correct, there will be no N2 left in the flask
Di- n- pentyl ether can be converted to 1- bromopentane by treatment with HBr through essentially a(n) ________ mechanism.
Answer:
SN1 mechanism
Explanation:
The mechanism of this reaction is shown in the image attached.
The Di- n- pentyl ether is first protonated. The CH3(CH2)4OH is now a good leaving group as shown.
The attack of the bromide ion on the cation formed completes the mechanism to yield 1- bromopentane as shown in the mechanism.
when a polar bond is formed between 2 atoms which atom receives a partial positive charge
Answer:
The less electronegative atom
Explanation:
Water contains polar bonds. Water is made up of oxygen and hydrogen. Oxygen is more electronegative then hydrogen so it is partial negative (because electron spend more time around oxygen in the polar bond), whereas, hydrogen has a partial positive charge as it is less electronegative (electrons spend less time around hydrogen in this polar bond).
write any two things that should be remembered while writing chemical equation
Answer:
the product and the reactant must be balanced
if u are required to give the mechanism if the reaction it must be written
Which 2 resonance forms destablize the carbocation intermediate if bezonitrile undergoes chlronation at the ortho or para positions
The question is incomplete, the complete question is shown in the image attached
Answer:
A and B
Explanation:
The electrophilic substitution of arenes yields a cation intermediate. The positive charge of the cation is delocalized over the entire ring.
The -CN group directs incoming electrophiles to the ortho/para position. The resonance structures for the chlorination of benzonitrile are shown in the question.
Recall that -CN is an electron withdrawing group. The resonance forms that destablize the carbocation intermediate are those in which the -CN group is directly attached to the carbon atom bearing the positive charge as in structures A and B.
1.Using the absorbance of the spinach extract and the equation of the trendline, determine the concentration of the extract solution. Report the concentration in moles/L (M).
2. Calculate the number of rams of chlorophyll-a in the 25ml, spinach solution.
3. Calculate the concentration of the chloropyhll-a soultion in spinach (mg chlorophyll-a/g spinach)
Trendline: y=1609x + .0055
Absorbance spinach extract lamda max: .329
Absorbacne spinach extract, 750 nm: .023
Corrected absorbance: .306
Mass of Spinach: .1876g Total Volume of spinach: 25mL
Answer:
Explanation:
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
∴
0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
No. of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
the volume = 25ml = (25/1000) L = 0.025 L
∴
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
From the given information:
We are to make use of the spinach absorbance extract which is the corrected absorbance (y) = 0.306ChlorophyllChlorophyll is any member of the class of the green pigments involved in the photosynthesis process.
And also the trendline equation:
y = 1609x + 0.0055
where,
x = absorbance of the spinach extract.
so 0.306 = 1609x + 0.0055
collecting the like terms
0.306 - 0.0055 = 1609x
0.3005 = 1609x
x = 0.3005/1609
x = 1.8676 × 10⁻⁴
x ≅ 0.0002 M
2. No.of grams for the chlorophyll can be computed as follows:
recall that:
molar mass of chlorophyll = 893.5 g/mol
The volume = 25ml = (25/1000) L = 0.025 L
Therefore:
In spinach solution, the no. of grams for the chlorophyll:
= (0.0002) mol/L × (893.5 g/mol) × (0.025) L
= 0.0044675 g
≅ 0.0045 g
3. In the spinach, the concentration of chlorophyll = no of grams of chlorophyll/ mass of the spinach
= 4.5 mg/0.1876 g
= 23.987 mg/g
≅ 24 mg/g
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54
Penny bought a club moss plant for her water garden. She needs to know how tall the plant will grow so she know
how much space it will need.
How tall will the plant likely grow?
O less than 5 centimeters because it is a seedless vascular plant
less than 5 centimeters because it is a nonvascular plant
O more than 5 centimeters because it is a seedless vascular plant
O more than 5 centimeters because it is a nonvascular plant
Answer:
less than 5 centimeters because it is a nonvascular plant
Explanation:
Mosses are a group of plants under the division Bryophyta. They are said to be the most primitive plant life in existence as they lack true roots, stems and leaves. They also lack vascular system, hence, they are regarded as non-vascular plants. They usually grow in very small sizes (about 0.2 - 10cm).
According to this question, Penny bought a club moss plant for her water garden and needs to know how tall the plant will grow so she know how much space it will need. Since it is a miss plant that lacks vascular tissues i.e. nonvascular, it will likely grow less than 5 centimeters in height.
Answer:
d
Explanation:
g n the following three compounds(1,2,3) arrange their relative reactivity towards the reagent CH3Cl / AlCl3. Justify your order
Answer:
3 > 2> 1
Explanation:
Aromatic compounds undergo electrophilic substitution reaction which passes through a positively charged intermediate to yield the product.
Substituted benzenes may be more or less reactive towards electrophilic aromatic substitution than benzene molecule depending on the nature of the substituent.
Certain substituents increase the ease of reaction of benzene towards aromatic substitution.
If we look at the compounds closely, we will notice that toluene reacts readily with CH3Cl / AlCl3. This is because, the methyl group is electron donating hence it stabilizes the positively charged intermediate produced in the reaction.
Carbonyl compounds are electron withdrawing substituents hence they decrease the magnitude of the positive charge and hence decrease the rate of electrophilic aromatic substitution.
Which of the following is the correct way to balance the following chemical question:
2SnO2 + 4H2 -> 2Sn + 4H2O
SnO2 + 2H2 -> Sn + 2H2O
a. Both equation I and II are balanced, but equation I is the correct way to write the balanced equation.
b. Can you divide equation II by another factor and still have it be correct? Why or why not?
c. In a complete sentence, write down a method you could use to determine if an equation is written in the correct way.
Answer:
i have no answer for part A
part B
the one that has a 4 can be divided by 2 because reducing
part c
you can determine if an equation is written in the correct way by balancing the equation as if it had not been done already.
If a student drops 2.3g pieces of magnesium into a flask of hydrochloric acid, this reaction occurs: Mg + 2HCl= MgCl2 + H2
How many liters of hydrogen can be produced at a pressure of 2 atm and a temperature of 298 K
Answer:
1.2 L
Explanation:
Step 1: Write the balanced equation
Mg + 2 HCl ⇒ MgCl₂ + H₂
Step 2: Calculate the moles corresponding to 2.3 g of Mg
The molar mass of Mg is 24.31 g/mol.
2.3 g × 1 mol/24.31 g = 0.095 mol
Step 3: Calculate the moles of H₂ produced
0.095 mol Mg × 1 mol H₂/1 mol Mg = 0.095 mol H₂
Step 4: Calculate the volume occupied by the hydrogen
We will use the ideal gas equation.
P × V = n × R × T
V = n × R × T/P
V = 0.095 mol × (0.0821 atm.L/mol.K) × 298 K/2 atm = 1.2 L
A vessel is filled at a rate of 3.41 cubic micrometers per minute. If the vessel has a volume of 54 liters, how many
seconds will it take to fill the vessel? provide a step buy step explanation.
Answer:
9.5x10¹⁷ s
Explanation:
First we convert 3.41 cubic micrometers (um³) to liters (L), as such:
3.41 um³ * [tex](\frac{1m}{10^6um} )^3*\frac{1000L}{1m^3}[/tex] = 3.41x10⁻¹⁵ LWith the converted rate of 3.41x10⁻¹⁵ L/min, we can calculate how many minutes it would take to fill a 54 L vessel:
54 L ÷ 3.41x10⁻¹⁵ L/min = 1.58x10¹⁶ minFinally we convert 1.58x10¹⁶ minutes to seconds:
1.58x10¹⁶ * 60 = 9.5x10¹⁷ sHow much would the freezing point of water decrease if 4 mol of sugar were added to 1kg of water?
Answer:
7.44 C is the answer of the question.
Explanation:
ype the correct answer in the box.
Calculate the density of the substance.
A sample of a substance has a mass of 4.2 grams and a volume of 6 milliliters. The density of this substance is grams/milliliter.
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Explanation:
here is your answer. Hope it helps
Calculate the mass of butane needed to produce 80.0g of carbon dioxide
Answer:
Multiply the number of moles of butane by its molar mass, 58.12g/mol, to produce the mass of butane. Mass of butane = 18.8g.
how many lone pair electrons are on the central oxygen atom in the Lewis structure for dinitrogen pentoxide 9
Answer:
Two
Explanation:
Lone pairs are electron pairs on an atom that resides only with one of the atoms in a molecule.
Dinitrogen pentaoxide is shown in the image attached. There are five oxygen atoms and two nitrogen atoms in the molecule. The molecule has a total of 40 valence electrons.
There are two electrons present on the central oxygen atom in the Lewis structure of dinitrogen pentaoxide as shown in the image attached.
Answer the following questions: (Questions about titration)
a. Why is it important to keep the NaOH solution covered at all times?
b. How will the molarity of NaOH solution be affected by its continued exposure to the atmosphere?
c. The pale pink color of the titration solution at the end point will fade to colorless after several minutes when exposed to the atmosphere. Account for this color change.
d. What volume (in mL) of 0.293 M Ba(OH)2 is required to neutralize 25.00 mL of 0.200M HNO3?
Answer:
Following are the solution to the given question:
Explanation:
For question a:
It is prevented that the atmospheric [tex]CO_2[/tex] through dissolving in the solution and make carbonic acid [tex](H_2CO_3)[/tex] which reacts with the [tex]NaOH:[/tex]
[tex]CO_2+ H_20\to H_2CO_3\\\\H_2CO_3 + NaOH \to NaHCO_3 +H_2O\\\\H_2CO_3 + 2 NaOH \to Na_2CO_3 + 2H_2O\\\\[/tex]
For question b:
For this, the [tex]NaOH[/tex] reacts with the dissolved [tex]CO_2[/tex] so, the molarity of the [tex]NaOH[/tex] will be decreased.
For question C:
In this, the Phenolphthalein is pink in the basic solution[tex](high \ pH)[/tex] and colorless throughout the acidic solution[tex](low\ pH)[/tex].
if the solution is exposed from the atmosphere, the [tex]CO_2[/tex] is from the air dissolving in the solution, and making the [tex]H_2CO_3[/tex] that gives the [tex]H^{+}\ ions[/tex]
[tex]\to[/tex] lower pH.
[tex]\to[/tex] colorless phenolphthalein
For question D:
[tex]Ba(OH)_2 + 2 HNO_3 \to Ba(NO_3)_2+ 2H_2O\\\\[/tex]
Calculating the moles of[tex]HNO_3 = volume \times \text{concentration of} HNO_3\\\\[/tex]
[tex]= \frac{25}{1000} \times 0.200\\\\= 0.005\ mol\\\\[/tex]
Calculating the moles of [tex]Ba(OH)_2= \frac{1}{2} \times\text{moles of}\ HNO_3\\\\[/tex]
[tex]=\frac{1}{2} \times 0.005\\\\= 0.0025 \ mol\\\\[/tex]
Calculating the volume of [tex]Ba(OH)_2=\frac{moles}{concentration\ of\ Ba(OH)_2}[/tex]
[tex]=\frac{0.0025}{0.0293}\\\\=0.08532\ L\\\\= 85.32 \ mL\\\\= 85.3\ mL[/tex]
Calculate the vapor pressure (in torr) at 298 K in a solution prepared by dissolving 46.8 g of the non-volatile non-electrolye glucose in 117 g of methanol. The vapor pressure of methanol at 298 K is 122.7 torr. Enter your answer to 2 decimal places.
Answer: The total partial pressure of the solution is 131.37 torr.
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For glucose:Given mass of glucose = 46.8 g
Molar mass of glucose = 180 g/mol
Plugging values in equation 1:
[tex]\text{Moles of glucose}=\frac{46.8g}{180g/mol}=0.26 mol[/tex]
For methanol:Given mass of methanol = 117 g
Molar mass of methanol = 32 g/mol
Plugging values in equation 1:
[tex]\text{Moles of methanol}=\frac{117g}{32g/mol}=3.66 mol[/tex]
Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:
[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex] .....(2)
where n is the number of moles
Putting values in equation 2:
[tex]\chi_{methanol}=\frac{3.66}{0.26+3.66}=0.934[/tex]
Raoult's law is the law used to calculate the partial pressure of the individual gases present in the mixture. The equation for Raoult's law follows:
[tex]p_A=\chi_A\times p_T[/tex] .....(3)
where [tex]p_A[/tex] is the partial pressure of component A in the mixture and [tex]p_T[/tex] is the total partial pressure of the mixture
We are given:
[tex]p_{methanol}=122.7torr\\\chi_{methanol}=0.934[/tex]
Putting values in equation 3, we get:
[tex]122.7torr=0.066\times p_T\\\\p_T=\frac{122.7torr}{0.934}=131.37torr[/tex]
Hence, the total partial pressure of the solution is 131.37 torr.
Which one of the following is an example of a balanced chemical reaction?
a. 8HCl + 2KMnO4 → 3Cl2 + 2MnO2 + 4H2O + 2KCl.
b. 6HCl + 2KMnO4 → 2Cl2 + 2MnO2 + 4H2O + 2KCl.
c. 2HCl + 2KMnO4 → Cl2 + MnO2 + 2H2O + 2KCl.
d. HCl + KMnO4 → Cl2 + MnO2 + H2O + KCl.
e. HCl + KMnO4 → Cl2 + MnO2 + 2H2O + KCl.
Answer:
Option a.
Explanation:
To determine which is a balanced chemical reaction, see the stoichiometry.
Stoichiometry coefficients are the numbers that appear before the compounds. These numbers indicate moles of substance.
Notice that the number of elements must be the same in both sides of the equation.
In this case, option a is the balanced chemical reaction.
8HCl + 2KMnO₄ → 3Cl₂ + 2MnO₂ + 4H₂O + 2KCl
8 moles of HCl react to 2 moles of potassium permanganate in order to produce 2 moles of magnessium dioxide, 3 moles of chlorine, 2 moles of potassium chloride and 4 moles of water.
8 H, 8 Cl, 2 K, 2 Mn and 8 O
Identify the intermolecular attractions for dimethyl ether and for ethyl alcohol. Which molecule is expected to be more soluble in water? Explain.
Answer:
See explanation
Explanation:
All molecules possess the London dispersion forces. However London dispersion forces is the only kind of intermolecular interaction that exists in nonpolar substances.
So, the only kind of intermolecular interaction that exists in dimethyl ether is London dispersion forces.
As for ethyl alcohol, the molecule is polar due to the presence of polar O-H bond. In addition to London dispersion forces, dipole-dipole interactions and specifically hydrogen bonding also occurs between the molecules.
Because ethyl alcohol is polar, it is more soluble in water than dimethyl ether.
CAN YOU PLEASE HELP ME
When Pt electrodes are used in the electrolysis of Kl(aq), a number of reactions are possible at the electrodes. Using a standard reduction potentials table predict which reaction is most likely to occur at the anode
anode is oxidation
so look at the reduction potential for Pt and Kl
the one with the smaller reduction potential will undergo oxidation
the one with the larger reduction potential will undergo reduction
you have to flip the equation that undergoes oxidation because the reduction table always gives reduction equations
The speed of light_____ meters per second
☛ 299,792,458 meters per second.
In water, Vanillin, C8H8O3, has a solubility of 0.070 moles of vanillin per liter of solution at 25C. What will be produced if 5.00 g of vanillin are added to 1 L of water at 25 C?
Answer:
The full amount (5.00 g) will be dissolved in 1 L of water at 25°C.
Explanation:
The molecular weight (MW) of Vanillin (C₈H₈O₃) is calculated from the chemical formula as follows:
MW(C₈H₈O₃) = (12 g/mol x 8) + (1 g/mol x 8) + (16 g/mol x 3) = 152 g/mol
If 0.070 mol of C₈H₈O₃ are soluble per liter of water at 25°C, the maximum mass that can be dissolved in 1 L is:
0.070 mol x 152 g/mol = 10.64 g
Since 5.00 g is lesser than the maximum amount that can be dissolved (10.64 g), the added amount will be completely dissolved in 1 L of water at 25°C.
How many ml of 0.24 M HBr solution are needed to react completely with 10.00 ml of 0.24 M Sr(OH)2 solution
Answer:
10mL
Explanation:
Using the formula as follows:
CaVa = CbVb
Where;
Ca = concentration of acid, HBr (M)
Cb = concentration of base, Sr(OH)2 (M)
Va = volume of acid, HBr (Litres)
Vb = volume of base, Sr(OH)2 (Litres)
According to the information given in this question;
Ca = 0.24M
Cb = 0.24M
Va = ?
Vb = 10.0ml
Using CaVa = CbVb
0.24 × Va = 0.24 × 10
0.24Va = 2.4
Va = 2.4 ÷ 0.24
Va = 10mL
10mL of HBr is needed.
The density of aluminum is 2.7 g/cm3.
Part A
What is its density in kilograms per cubic meter?
Express your answer in kilograms per cubic meter to two significant figures.
Answer:
2700 kg/m³
Explanation:
First let's convert 2.7 g/cm³ to kg/cm³, keeping in mind that 1 kilogram equals 1000 grams:
2.7 g/cm³ * [tex]\frac{1kg}{1000g}[/tex] = 0.0027 kg/cm³Finally we need to convert 0.0027 kg/cm³ to kg/m³, keeping in mind that 1 meter equals 100 centimeters, as follows:
0.0027 kg/cm³ * [tex](\frac{100cm}{1m} )^3[/tex] = 2700 kg/m³The answer is 2700 kg/m³.
Suppose 20.8 g of sodium iodide is dissolved in 250. mL of a 0.70 M aqueous solution of silver nitrate. Calculate the final molarity of ALL IONS in the solution. You can assume the volume of the solution doesn't change when the sodium iodide is dissolved in it. Round your answer to 3 significant digits.
Answer:
[Ag+] = [NO3-] = 0.700M
0.555M = [Na+] = [I-]
Explanation:
To solve this question we need to find the moles of sodium iodide, NaI, using its molar mass -. With the moles and the volume we can find the molarity of Na+ and I-. The molarity of the ions of silver nitrate, AgNO3 doesn't change because we are assuming the volume doesn't change:
Molarity Ag⁺ = Molarity NO₃⁻ = 0.700M
Moles NaI -Molar mass: 149.89g/mol-
20.8g NaI * (1mol/149.89g) = 0.0139 moles NaI
Molarity:
0.0139 moles NaI / 0.250L = 0.555M = [Na+] = [I-]
Perform the following operation and express the answer in scientific notation.
7.296×10² ÷ 9.6×10^-9
Answer:
7.6×10¹⁰
Explanation:
7.296×10²÷9.6×10⁻⁹
To solve such problem,
We group the whole number ans solved seperately and also group the indices and solve the seperately
Step1 : 7.296/9.6 = 0.76
Step 2: applying the law of indices,
10²÷10⁻⁹ = 10⁽²⁺⁹⁾ = 10¹¹
Therefore,
7.296×10²÷9.6×10⁻⁹ = 0.76×10¹¹ = 7.6×10¹⁰