Answer:
Specific gravity of the saturated solution is 2
Explanation:
The specific gravity is defined as the ratio between density of a solution (In this case, saturated solution of potassium iodide, KI) and the density of water. Assuming density of water is 1:
Specific gravity = Density
The density is the ratio between the mass of the solution and its volume.
In 100mL of water, the mass of KI that can be dissolved is:
100mL * (1g KI / 0.7mL) = 143g of KI
That means all the 100g of KI are dissolved (Mass solute)
As the volume of water is 100mL, the mass is 100g (Mass solvent)
The mass of the solution is 100g + 100g = 200g
In a volume of 100mL, the density of the solution is:
200g / 100mL = 2g/mL.
The specific gravity has no units, that means specific gravity of the saturated solution is 2
Biphenyl, C12H10, is a nonvolatile, nonionizing solute that is soluble in benzene, C6H6.
At 25 ∘C, the vapor pressure of pure benzene is 100.84 Torr. What is the vapor pressure of a solution made from dissolving 10.9 g of biphenyl in 25.3 g of benzene?
Answer:
The correct answer is - 83. torr
Explanation:
We know that:
p = X solvent * P pure solvent,
where, X solvent = number of moles of solvent / total number of moles.
in this solution, solute is 10.9 g of C12 H10 and the solvent is 25.3 g C6H6.
molar mass of C6H6 = 6 * 12 g/mol + 6 * 1g/mol = 78 g/mol ( => moles of solvent = mass in grams / molar mass)
moles of solvent = 25.3 g / 78 g/mol = 0.3243 mol
molar mass of C12H10 = 12 * 12g/mol + 10*1g/mol = 154 g/mol
moles of solute = 10.9 g / 154 g/mol = 0.07077 mol
=> X solvent = 0.3243 / (0.3243 + 0.07077) = 0.8208
=> p = 0.8208 * 100.84 torr = 82.77 torr ≈ 83.0 torr
Answer: 83.0 torr
Postlab Questions (2 pts ea; 8 pts total be specific and answer all in complete sentences): 1. How would you distinguish benzaldehyde and acetophenone by the results of their qualitative tests
Answer:
Using the Iodoform test, we can differentiate both compounds.
Explanation:
Benzaldehyde (C6H5CHO -an aldehyde) and Acetophenone (C6H5COCH3 - a methyl ketone) can be differentiated by reacting both compounds with iodine in a basic (NaOH) solutions.
The methyl ketone (acetophenone) gives a pale yellow precipitate of triiodomethane (iodoform) while the aldehyde (benzaldehyde) would not react.
This is known as the IODOFORM test and is indicative for methyl ketones
A 0.245-L flask contains 0.467 mol co2 at 159 °c. Calculate the pressure using the ideal gas law.
Answer:
Pressure, P = 67.57 atm
Explanation:
Given the following data;
Volume = 0.245 LNumber of moles = 0.467 molesTemperature = 159°CIdeal gas constant, R = 0.08206 L·atm/mol·KConversion:
We would convert the value of the temperature in Celsius to Kelvin.
T = 273 + °C
T = 273 + 159
T = 432 Kelvin
To find the pressure of the gas, we would use the ideal gas law;
PV = nRT
Where;
P is the pressure.V is the volume.n is the number of moles of substance.R is the ideal gas constant.T is the temperature.Making P the subject of formula, we have;
[tex] P = \frac {nRT}{V} [/tex]
Substituting into the formula, we have;
[tex] P = \frac {0.467*0.08206*432}{0.245} [/tex]
[tex] P = \frac {16.5551}{0.245} [/tex]
Pressure, P = 67.57 atm
what is irrigation?Describe two methods of irrigation which conserve water
The process of watering the crops is called irrigation.
Any two methods of irrigation are:
(i) Sprinkler system:This system is used on the uneven land where less water is available. The perpendicular pipes, having rotating nozzles on top, are joined to the main pipeline at regular intervals. Water is allowed to flow through main pipe under pressure, which escapes from the rotating nozzles. In this way water gets sprinkled on the crop.
(ii) Drip irrigation:This system is used to save water as it allows the water to flow drop by drop at the roots of the plants. It is the best technique for watering fruit plants, gardens and trees. Water is not wasted at all.
g A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0 atm. Calculate the amount of work done on the system in Joules. (1 L.atm
Answer:
The amount of work done on the system is 18234 J and the final positive sign means that this work corresponds to an increase in internal energy of the gas.
Explanation:
Thermodynamic work is called the transfer of energy between the system and the environment by methods that do not depend on the difference in temperatures between the two. When a system is compressed or expanded, a thermodynamic work is produced which is called pressure-volume work (p - v).
The pressure-volume work done by a system that compresses or expands at constant pressure is given by the expression:
W system= -p*∆V
Where:
W system: Work exchanged by the system with the environment. Its unit of measure in the International System is the joule (J) p: Pressure. Its unit of measurement in the International System is the pascal (Pa) ∆V: Volume variation (∆V = Vf - Vi). Its unit of measurement in the International System is cubic meter (m³)In this case:
p= 10 atm= 1.013*10⁶ Pa (being 1 atm= 101325 Pa)ΔV= 2 L- 20 L= -18 L= -0.018 m³ (being 1 L=0.001 m³)Replacing:
W system= -1.013*10⁶ Pa* (-0.018 m³)
Solving:
W system= 18234 J
The amount of work done on the system is 18234 J and the final positive sign means that this work corresponds to an increase in internal energy of the gas.
Can you please answer the 5 attached questions?
Answer:
10.4%
Explanation:
Recall that the formula for percent solution = mass of solute/mass of solution * 100
Mass of solute = 2.07 g
Mass of solution = 19.9 g
Hence mass percent of solute = 2.07/19.9 * 100
= 10.4%
Suppose that a certain atom possesses only four distinct energy levels. Assuming that all transitions between levels are possible, how many spectral lines will this atom exhibit
Answer:
Following are the response to the given question:
Explanation:
The number of shells
n = 4
Calculating the spectral line:
[tex]= \frac{n(n-1)}{2}\\\\ = \frac{4(4-1)}{2} \\\\= \frac{4\times 3}{2}\\\\ = \frac{12}{2}\\\\ = 6[/tex]
High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa) to about 60,000 kPa (60,000,000 Pa). It is often convenient to know the pressure in torr. If an HPLC procedure is running at a pressure of 6.50×106 Pa , what is its running pressure in torr?
Answer:
1 kpa = 7.5 torr
1.75*10^7 pa = 1.75*10^4 Kpa = (1.75/7.5)*10^4 torr = 2333 torr
Explanation:
A compound contains only carbon, hydrogen, and oxygen. Combustion of 65.76 g of the compound yields 96.38 g of CO2 and 39.46 g of H2O.
The molar mass of the compound is 90.078 g/mol.
1. Calculate the grams of carbon (C) in 65.76 g of the compound:
2. Calculate the grams of hydrogen (H) in 65.76 g of the compound.
3. Calculate the grams of oxygen (O) in 65.76 g of the compound.
Answer:
1. 26.30 g C.
2. 4.42 g H.
3. 35.04 g O.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to calculate the required as follows:
1. Here, the only source of carbon is in CO2, and thus, we calculate the grams of carbon from the produced grams of this substance:
[tex]m_C=96.38gCO_2*\frac{1molCO_2}{44.01gCO_2} *\frac{1molC}{1molO_2} *\frac{12.01gC}{1molC} =26.30g[/tex]
2. Here, the only source of hydrogen is in H2O, and thus, we calculate the grams of hydrogen from the produced grams of this substance:
[tex]m_H=39.46gH_2O*\frac{1molH_2O}{18.02gH_2O} *\frac{2molH}{1molH_2O} *\frac{1.01gH}{1molH} =4.42gH[/tex]
3. Here, we subtract the mass of H and C from the mass of the sample, to obtain the mass of oxygen:
[tex]m_O=65.76g-26.30g-4.42g\\\\m_O=35.04g[/tex]
Regards!
We need to prepare 0.0021 M solution of C2SO4. But there are only 80.7 grams of the chemical available. What is the maximum volume that can be prepared?
Answer:
320 L
Explanation:
We'll begin by calculating the number of mole in 80.7 g of C₂SO₄. This can be obtained as follow:
Mass of C₂SO₄ = 80.7 g
Molar mass of C₂SO₄ = (12×2) + 32 + (16×4)
= 24 + 32 + 64
= 120 g/mol
Mole of C₂SO₄ =?
Mole = mass /molar mass
Mole of C₂SO₄ = 80.7 / 120
Mole of C₂SO₄ = 0.6725 mole
Finally, we shall determine the volume. This can be obtained as follow:
Mole of C₂SO₄ = 0.6725 mole
Molarity = 0.0021 M
Volume =?
Molarity = mole / Volume
0.0021 = 0.6725 / Volume
Cross multiply
0.0021 × Volume = 0.6725
Divide both side by 0.0021
Volume = 0.6725 / 0.0021
Volume ≈ 320 L
Thus, the volume that can be prepared is approximately 320 L.
A reaction is thermodynamically unstable (spontaneous) but no change is observed. The reaction is probably Select the correct answer below: kinetically unstable. kinetically stable. thermodynamically stable but kinetically unstable. None of the above
Answer:
kinetically stable.
Explanation:
When we say that a system is thermodynamically unstable, it means that there is still a state in which the system is expected to have lower energy than it currently has. A thermodynamically unstable system is yet to attain equilibrium hence it can still undergo further chemical processes in order to attain thermodynamic stability.
When we say that a system is kinetically stable, it means that the activation energy or energy barrier for the reaction system is high. Thus reactants are not easily converted into products. The reaction system remains the same for a long while without change.
Finally, when a reaction is thermodynamically unstable (spontaneous) but no change is observed, the reaction is kinetically stable.
2. 27.8 mL of an unknown were added to a 50.0-mL flask that weighs 464.7 g. The total mass of the flask and the liquid is 552.4 g. Calculate the density of the liquid in Lbs/ in3.
Answer:
[tex]d=4.24x10^{-4}\frac{lb}{in^3}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to set the equation for the calculation of density and mass divided by volume:
[tex]d=\frac{m}{V}[/tex]
Thus, we can find the mass of the unknown by subtracting the total mass of the liquid to the mass of the flask and the liquid:
[tex]m=552.4g-464.7g=87.7g[/tex]
So that we are now able to calculate the density in g/mL first:
[tex]d=\frac{87.7g}{27.8mL}=3.15g/mL[/tex]
Now, we proceed to the conversion to lb/in³ by using the following setup:
[tex]d=3.15\frac{g}{mL}*\frac{1lb}{453.6g}*\frac{1in^3}{16.3871mL}\\\\d=4.24x10^{-4}\frac{lb}{in^3}[/tex]
Regards!
A 8.249 gram sample of copper is heated in the presence of excess fluorine. A metal fluoride is formed with a mass of 13.18 g. Determine the empirical formula of the metal fluoride.
Answer:
[tex]CuF_2[/tex] the empirical formula of the metal fluoride.
Explanation:
Mass of copper heated = 8.249 g
Mass of copper fluoride formed = 13.18 g
Mass of fluorine gas in copper fluoride = x
[tex]13.18 g = 8.249 g + x\\x= 13.18 - 8.249 g = 4.931 g[/tex]
Moles of copper :
[tex]= \frac{8.249 g}{63.546 g/mol}=0.1298 mol[/tex]
Moles of fluorine:
[tex]= \frac{4.931 g}{18.998 g/mol}=0.2596 mol[/tex]
For the empirical formula divide the smallest mole of an element with all the moles of elements present in the compound.
[tex]Copper= \frac{0.1298 mol}{0.1298 mol}=1\\Fluorine = \frac{0.2596 mol}{0.1298 mol}=2[/tex]
The empirical formula of the copper fluoride = [tex]CuF_2[/tex]
[tex]CuF_2[/tex] the empirical formula of the metal fluoride.
why beta carbon hydrogen is easily replaceable but not alpha carbon hydrogen
Answer:
Four common types of reactions involving carbonyl reactions: 1) nucleophilic addition; 2) nucleophilic acyl substitution; 3) alpha substitution; 4) carbonyl condensations. The first two were previously discussed and the second two involve the properties of the carbon directly adjacent to the carbonyls, α carbons.
Alpha-substitution reactions results in the replacement of an H attached to the alpha carbon with an electrophile.
The nucleophile in these reactions are new and called enols and enolates.
Explanation:
The carbon in the carbonyl is the reference point and the alpha carbon is adjacent to the carbonyl carbon.
Hydrogen atoms attached the these carbons denoted with Greek letters will have the same designation, so an alpha hydrogen is attached to an alpha carbon.
Aldehyde hydrogens not given Greek leters.
α hydrogens display unusual acidity, due to the resonance stabilization of the carbanion conjugate base, called an enolate.
Tautomers are readily interconverted constitutional isomers, usually distinguished by a different location for an atom or a group, which is different than resonance.
The tautomerization in this chapter focuses on the carbonyl group with alpha hydrogen, which undergo keto-enol tautomerism.
Keto refers to the tautomer containing the carbonyl while enol implies a double bond and a hydroxyl group present in the tautomer.
The keto-enol tautomerization equilibrium is dependent on stabilization factors of both the keto tautomer and the enol tautomer, though the keto form is typically favored for simple carbonyl compounds.
The 1,3 arrangement of two carbonyl groups can work synergistically to stabilize the enol tautomer, increasing the amount present at equilibrium.
The positioning of the carbonyl groups in the 1,3 arrangement allows for the formation of a stabilizing intramolecular hydrogen bond between the hydroxyl group of the enol and the carbonyl oxygen as well as the alkene group of the enol tautomer is also conjugated with the carbonyl double bond which provides additional stabilization.
Aromaticity can also stabilize the enol tautomer over the keto tautomer.
Under neutral conditions, the tautomerization is slow, but both acid and base catalysts can be utilized to speed the reaction up.
Biological enol forming reactions use isomerase enzymes to catalyze the shifting of a carbonyl group in sugar molecules, often converting between a ketose and an aldose in a process called carbonyl isomerization.
Complete and balance the following chemical equations. Identify the reaction type as: combination, decomposition, single replacement, double replacement, or combustion.
Products:
Magnesium Oxide + Carbon dioxide.
a) MgCO₃ (Heat is supplied to the reaction (triangle over a arrow) -> Reaction type:
Products:
Aluminum Oxide
b) Al + O₂ -> Reaction type:
Answer:
the first one is a decomposition reaction
the second one is also a synthesis reaction
Solution:-1
[tex]\boxed{\sf {MgCO_3\atop Magnesium\:Carbonate}\overset{\Delta H}{\longrightarrow}{MgO\atop Magnesium \:Oxide}+{CO_2\atop Carbon\:Dioxide}}[/tex]
It is a thermal decomposition reaction
Solution:-2:-
[tex]\boxed{\sf {4Al\atop Aluminium}+{3O_2\atop Oxygen}\longrightarrow{2Al_2O_3\atop Aluminium\:oxide}}[/tex]
It is a combination reaction.
4.If 15.00 mL of 3.00 M potassium iodide is needed to reach the equivalence point with 10.00 mL of lead (Il) nitrate, determine the molarity of the lead (Il) nitrate solution
Answer:
2.25 M
Explanation:
The reaction that takes place is:
2KI + Pb(NO₂)₃ → PbI₂ + 2KNO₃First we calculate how many potassium iodide moles reacted, using the given volume and concentration:
15.00 mL * 3.00 M = 45 mmol KIThen we convert 45 mmoles of KI into mmoles of Pb(NO₂)₃, using the stoichiometric coefficients of the balanced reaction:
45 mmol KI * [tex]\frac{1mmolPb(NO_3)_2}{2mmolKI}[/tex] = 22.5 mmol Pb(NO₂)₃Finally we calculate the molarity of the Pb(NO₂)₃ solution, using the calculated number of moles and given volume:
22.5 mmol Pb(NO₂)₃ / 10.00 mL = 2.25 MAmines and amides are organic compounds that contain nitrogen. Amines are ammonia derivatives, in which at least one hydrogen atom is replaced by an organic substituent. Methylamine is a simple amine in which one of the hydrogen atoms of ammonia is replaced by a methyl group:
Answer:
Following are the solution to the given question:
Explanation:
Identify effective techniques for accurate pipet use. Select all that apply. Select one or more: Measure liquid by aligning the meniscus with the volume line. Leave any air bubbles in a pipet that occur after drawing up liquid. Do not let liquid enter the pipet bulb or pump. Use the pipet bulb to force the last drop out of the tip.
Answer:
Measure liquid by aligning the meniscus with the volume line.
Explanation:
A pipette is an instrument specially made for measuring a small volume of liquid.
The pipette comes in various sizes to be used in measuring various volumes of liquid. Generally, the pipette has a volume line which helps us to measure a liquid.
A liquid is measured by aligning the meniscus with the volume line.
If a precipitation reaction occurs, what will be the products of the unbalanced
reaction shown below?
AgNO3(aq) + NaCl(aq) →
Solubility Table
A. AgCl(s) + NaNO3(s)
B. AgCl(s) + NaNO3(aq)
C. No precipitate will form.
D. AgCl(aq) + NaNO3(s)
Answer:
[tex]{ \sf{B. \: AgCl _{(s)} + NaNO _{3(aq)}}}[/tex]
Explanation:
Silver chloride precipitates out because it has a low value of Ksp.
Identify each of the following half-reactions as either an oxidation half-reaction or a reduction half-reaction.
half-reaction identification
Cu+(aq)--->Cu2+(aq) + e- _________
I2(s) + 2e--->2I-(aq) _________
Answer:
Cu+(aq)--->Cu2+(aq) + e- : oxidation
reason: there is loss of electrons.
I2(s) + 2e--->2I-(aq) : reduction
reason: There is reduction of electrons.
which of the following kb values represents the weakest base?
Answer:
the weakest base will have a higher Kb value since it will be closer to an acid than a base
7 kb values represents the weakest base.
What is kb value?Kb is the base dissociation constant which is a measure of how completely a base dissociates into its component ions in water. pKb is define as the negative base-10 logarithm of the base dissociation constant (Kb) of a solution.
Ka is define as the acid dissociation constant while pKa is the -log of this constant. Kb is define as the base dissociation constant, while pKb is the -log of the constant.
The acid and base dissociation constants are usually expressed in terms of moles per liter (mol/L).
Thus, 7 kb values represents the weakest base.
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A student pours a few drops of vinegar onto limestone and it starts bubbling. What kind of reaction is this? How does it relate to chemical weathering, monuments and statues?
Answer:
The correct answer is - acid-base reaction or chemical weathering.
Explanation:
Vinegar is an acid that dissolves a material that is commonly found and known as calcium carbonate present in the limestone. When these two, vinegar mix with calcium carbonate of the limestone, the atoms in the acetic acid and the calcium carbonate come apart and rearrange in different ways to make new chemicals.
This rearrangement results in the release of carbon dioxide as a stream of bubbles. It is a form of weathering called chemical weathering and many monuments are based on rocks that have limestones in their composition and acid rain work similar to vinegar.
help plsssssssssssss
Answer:
The rate of the forward reaction equals the rate of the reverse reaction.
Explanation:
To know which option is correct, it important that we know what dynamic equilibrium is all about.
We'll begin by defining chemical equilibrium.
A chemical system is said to be in chemical equilibrium when there is no observable change in the properperties of the chemical system.
Dynamic equilibrium on the other hand can be defined as a state in which the forward and backward reaction is occurring at the same time. Thus, in dynamic equilibrium, the rate of the forward reaction is equal to the rate of the backward (i.e reverse) reaction.
An experimental drug, D, is known to decompose in the blood stream. Tripling the concentration of the drug increases the decomposition rate by a factor of nine. Write the rate law for decomposition of D.
Answer:
R=k[D]^2
Explanation:
Given that it is a decomposition reaction;
D--->product
Hence;
The rate law is;
R= k[D]^x ----(1)
When we triple the concentration of D we have;
[D]' = [3D]^x
Therefore;
R'= 3R
R'= k[D]'----(2)
Hence dividing (1) by (2);
R/R' = k[D]^x/k[D]'
R/9R = k[D]^x/k[3D]^x
1/9 = 1/3^x (take inverse of both sides)
9 = 3^x
3^2 = 3^x
x= 2
Hence the rate law;
R=k[D]^2
In aqueous solution the Hg2+ ion forms a complex with four iodide anions. Write the formation constant expression for the equilibrium between the hydrated metal ion and the aqueous complex. Under that, write the balanced chemical equation for the first step in the formation of the complex.
Answer:
Following are the solution to the given question:
Explanation:
In the aqueous solution of [tex]Hg^{2+}[/tex] ion is used to represent a [tex][Hg(H_2O)_4]^{2+}[/tex].
It is used to form a complex with iodide ions as [tex][Hgl_4]^{2-}[/tex].
Conversion reaction:
[tex][Hg(H_2O)_4]^{2+} +4I^{-} \to [HgI_4]^{2-}+4H_20[/tex]
Following are the formation constants:
[tex]k_f=\frac{[HgI_4]^{2-}}{[Hg(H_2O)_4]^{2+} [I^{-}]^4}[/tex]
Following are the first step to the conversion:
[tex][Hg(H_2O)_4]^{2+} +I^{-} \to [HgI(H_2O)_3]^{+}+H_20[/tex]
4. A salvage operator recovered coins believed to be gold. A sample weighed 385.000g and has a volume of 20.0mL. Were the coins gold (Density= 19.3g/mL) or yellow brass (Density =8.47g/mL)? Show your calculation and explain your answer.
Answer:
The coins are gold
Explanation:
To solve this question we need to find the density of the sample knowing that density is the ratio between the mass of a sample (385.000g) and the volume that is occupying (20.0mL).
Density is:
385.000g / 20.0mL = 19.3g/mL
As the density of the sample is equal to the density of gold:
The coins are goldOleic acid and elaidic acid are isomeric alkenes.
a. True
b. False
Answer:
False
Explanation:
Because Elaidic acid is an isomer of oleic acid. I really hope this helps you.
Physical and psychological dependence, high-risk behaviour, and chronic high blood
pressure can result from excessive use of
Answer:
Physical and psychological dependence is high, and withdrawal symptoms include watery eyes, runny nose, loss of appetite, irritability, tremors, panic, abdominal cramps and diarrhea, nausea, chills, and sweating. Use of contaminated syringes/needles to inject drugs may result in serious blood borne infections such as HIV-AIDS and hepatitis.
You will observe a weak acid-strong base titration in this experiment. Select all statements that are true about weak acid-strong base titrations.
A. Weak acid-strong base titrations always start at a higher pH than strong acid-strong base titrations, no matter the initial concentration.
B. The pH is less than 7 at the equivalence point.
C. The pH is greater than 7 at the equivalence point.
D. Half way to the equivalence point, a buffer region is observed.
Answer:
The pH is greater than 7 at the equivalence point.
Explanation:
Equivalence point is the point where the acid reacts with the base as stipulated in the equation of the reaction.
When a weak acid and a strong base are titrated, the pH of the solution at equivalence point is actually found to be around about pH ~ 9.
Hence, for a weak acid and strong base titration, The pH is greater than 7 at the equivalence point.
A titration between a weak acid and a strong base yields a solution whose pH is greater than 7 at the equivalence point.
What are weak acids?Weak acids are acids which only ionize partially in aqueous solutions.
When weak acids are dissolved in water, they produce only few hydrogen ions.
A strong base on the other hand ionizes completely to produce hydroxide ions in aqueous solutions.
The titration of a weak acid and a strong base gives a solution whose pH is greater than 7 at equivalence point.
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The standard reduction potential for O2 in acid is 1.23 V, according to Appendix E. Calculate the reduction potential for O2 at pH 7, for all other conditions being standard.
a. 0.40 V
b. 1.13 V
c. 1.23 V
d. 0.82 V
e. 1.64 V
Answer:
a. +0.40 V
Explanation:
Reduction of O2 in acid medium is +1.23 V. The reduction of O2 in basic medium will be calculated by subtracting equation of acidic medium from equation in base medium.
Kw^4 = [10^-14 ] ^ 4
solving we get -0.8274
Subtracting the value from oxygen reduction in acidic medium;
+ 1.23 - 0.8274 = +0.4026
