A student was given a solid containing a mixture of nitrate salts. The sample completely dissolved in water, and upon addition of dilute HCl , no precipitate formed. The pH was lowered to about 1 and H2S was bubbled through the solution. No precipitate formed. The pH was adjusted to 8 and H2S was again bubbled in. This time, a precipitate formed. Which compounds might have been present in the unknown?
a. Ca(NO3)2
b. AgNO3
c. Fe(NO3)3
d. Cr(NO3)3
e. Cu(NO3)2
f. KNO3
g. Bi(NO3)2
Answer:
Fe(NO3)3, Cr(NO3)3, Co(NO3)3
Explanation:
According to the question, no precipitate is observed when HCl was added. This means that we must rule out AgNO3.
Again, the sulphides of Cu^2+, Bi^3+ are soluble in acidic medium but according to the question, the sulphides do not precipitate at low pH hence Cu(NO3)2 and Bi(NO3)3 are both ruled out.
The sulphides of Fe^3+, Cr^3+ and Co^3+ all form precipitate in basic solution hence Fe(NO3)3, Cr(NO3)3, Co(NO3)3 may be present.
The presence of Ca(NO3)2 and KNO3 may be confirmed by flame tests.
Give the IUPAC and common name
Answer:
IUPAC Name:
N-ethyl-N-methylaniline
Common Name:
Benzenamine
Write chemical equations for the reactions that occur when solutions of the following substances are mixed:
a. HNO₂ (nitrous acid) and C₂H₇NO (aq) ethanolamine, a base.
b. H₃O+ and F-
a) HNO₂ + C₂H₇NO → N₂ + C₂H₆O + H₂O
b) H₃O⁺ + F⁻ → HF + H₂O
[tex]\large\color{lime}\boxed{\colorbox{black}{Answer : - }}[/tex]
a) HNO₂ + C₂H₇NO → N₂ + C₂H₆O + H₂O
b) H₃O⁺ + F⁻ → HF + H₂O
Determine the number of atoms of O in 60.1 moles of Fe₂(SO₃)₃.
Answer:
3.310308*10^26
Explanation:
nO=9nFe2(SO3)3=9*60.1=540.9 moles
number of atoms: 540.9*6.02*10^23
how many moles of lithium atoms are contained in 5.2 g of lithium
Answer:
[tex]\boxed {\boxed {\sf 0.75 \ mol \ Li}}[/tex]
Explanation:
We are asked to convert 5.2 grams of lithium to moles of lithium.
1. Molar MassTo convert from grams to moles, we need the molar mass. This is the measurement of the mass in 1 mole of a substance. It can be found on the Periodic Table because it is the same value as the atomic mass, but the units are grams per mole instead of atomic mass units.
Look up the molar mass of lithium.
Li: 6.94 g/mol 2. Convert Grams to MolesCreate a ratio using the molar mass of lithium.
[tex]\frac { 6.94 \ g \ Li}{ 1 \ mol \ Li}[/tex]
Multiply by the value we are converting: 5.2 grams of lithium.
[tex]5.2 \ g \ Li *\frac { 6.94 \ g \ Li}{ 1 \ mol \ Li}[/tex]
Flip the ratio so the units of grams of lithium cancel.
[tex]5.2 \ g \ Li *\frac{ 1 \ mol \ Li} { 6.94 \ g \ Li}[/tex]
[tex]5.2 *\frac{ 1 \ mol \ Li} { 6.94 }[/tex]
[tex]\frac{5.2} { 6.94 } \ mol \ LI[/tex]
[tex]0.749279538905 \ mol \ Li[/tex]
3. RoundThe original measurement of grams (5.2) has 2 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 9 in the thousandths place to the right tells us to round the 4 up to a 5.
[tex]0.75 \ mol \ Li[/tex]
5.2 grams of lithium is equal to 0.75 moles of lithium atoms.
A strawberry nutritional drink used for a liquid diet is flavored with methyl butanoate. Draw the structure of methyl butanoate.
Answer:
See explanation and image attached
Explanation:
Methyl butanoate is an ester. Esters have the general molecular formula, RCOOR where the two Rs may represent the same or different alkyl groups.
Methyl butanoate is has a fruity odor, smelling like apples or pineapples fragrance. It is also called methyl butyrate.
The structure of the compound is shown in the image attached to this answer.
Which substance would be the most soluble in gasoline?
Select one:
A. hexane
B. NaNO3
C. HCI
D. water
E. Nacl
I think the answer most be d
In chemistry like dissolves like hence hexane will dissolve in gasoline.
Dissolution stems from intermolecular interaction between solute and solvent molecules.
If this interaction can not occur, dissolution of one substance in another is impossible.
Hexane dissolves in gasoline because the both substances are non-polar and can interact with each other effectively.
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What is a litmus solution? How is it obtained?
Draw the organic product(s) of the following reaction.
NaNH2/ NH3(l)
CH2CH2CH2-Câ¡C -C-H â
Answer:
H-C = C-H NaNH2 [tex]\ \to \0}[/tex] H-C = CNa
H-C = C - CH2 CH2 CH2 CH3
Explanation:
NaNH2 acts as base in this reaction. The organic products released after the reaction of carbon hydrogen atom with sodium amide. These products released after the chemical reaction when carbon and hydrogen atom reacts and NaNH2 acts as base then substitution nucleophilic reaction takes place.
Which technique would be best for separating sand and water?
A. filtration
B. distillation
C. chromatography
D. evaporation
Answer:
A. filtration
Hope it helps
3 attempts left Be sure to answer all parts. Which indicators that would be suitable for each of the following titrations: (a) CH3NH2 with HBr thymol blue bromophenol blue methyl orange methyl red chlorophenol blue bromothymol blue cresol red phenolphthalein (b) HNO3 with NaOH thymol blue bromophenol blue methyl orange methyl red chlorophenol blue bromothymol blue cresol red phenolphthalein (c) HNO2 with KOH thymol blue bromophenol blue methyl orange methyl red chlorophenol blue bromothymol blue cresol red phenolphthalein
An indicator usually signals the endpoint of a neutralization reaction by undergoing a color change. They aid in discovering the point of equivalence of a titration.
The kind of indicator used depends on the nature of acid/base reacted.
In the case of CH3NH2 with HBr which strong acid and weak base titration, suitable indicators include; bromophenol blue, methyl orange, methyl red, and chlorophenol blue.
In the case of HNO3 with NaOH, this is a strong acid, strong base titration hence phenolphthalein, methyl red, chlorophenol, and bromothymol blue cresol red blue are suitable indicators.
In the case of HNO2 with KOH, this a weak acid, strong base titration and the suitable indicators are cresol red and phenolphthalein.
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The element Co exists in two oxidation states, Co(II) and Co(III), and the ions form many complexes. The rate at which one of the complexes of Co(III) was reduced by Fe(II) in water was measured. Determine the activation energy of the reaction from the following data:
T(K) K(s^-1)
293 0.054
298 0.100
We measured the Fe(II) reduction of one of the Co(III) complexes by water at a rate of about 0.545 kJ/mol (to three significant figures).
How is activation energy determined?Calculating a Reaction's Activation Energy A reaction's rate is influenced by the temperature at which it is carried out. The molecules travel more quickly and clash more frequently as the temperature rises. Moreover, the molecules contain greater kinetic energy.
We can use the Arrhenius equation to calculate the reaction's activation energy:
k = A × exp(-Ea/RT)
When the activation energy Ea, the rate constant k, the gas constant R, and the temperature T in Kelvin are all present.
Finding the natural logarithm of the equation's two sides results in:
ln(k) = ln(A) - (Ea/RT)
This equation can be rearranged to take a linear form:
ln(k) = (-Ea/R) × (1/T) + ln(A)
y = mx + b, where (1/T) is x, (-Ea/R) is the slope, and ln(A) is the y-intercept, has the form of a linear equation.
We can get the slope of the line using the given data:
slope = (-Ea/R) = (ln(k2/k1)) / (1/T2 - 1/T1)
where the rate constants for temperatures T1 and T2, respectively, are k1 and k2.
substituting the specified values:
k1 = 0.054s⁻¹ at 293 K
k2 = 0.100s⁻¹ at 298 K
T1 = 293 K
T2 = 298 K
slope = (-Ea/R)
= (ln(0.100/0.054)) / (1/298 - 1/293)
= 65.5 kJ/mol
Therefore, the activation energy of the reaction is:
Ea = slope * R = 65.5 kJ/mol × 8.314 J/mol-K = 545 J/mol
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What is Bose Einstein state of matter and their examples
Answer:
A BEC ( Bose - Einstein condensate ) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero is called BEC.
Examples - Superconductors and superfluids are the two examples of BEC.
Explanation:
most naturally occurring oxygen is
Equimolar solutions of A and B are mixed and the reaction is allowed to reach equilibrium. Write down the reactio that correctly describes the relative concentrations at equilibrium?
Complete Question
Complete Question is attached below
Answer:
Option A
[tex]D=A[/tex] And [tex]C>A[/tex]
Explanation:
From the question, we are told that:
The Chemical Reaction
[tex]2A_{aq}+B_{aq} \leftrightarrow 3C_{aq}+2D_{aq}[/tex]
Generally, the equation for Equilibrium constant is mathematically given by
[tex]K=\frac{C^c*D^d}{A^a*B^b}[/tex]
Therefore
[tex]K=\frac{C^3*D^d}{A^2*B^b}[/tex]
Hence we conculde
[tex]D=A[/tex] And [tex]C>A[/tex]
Therefore Option A
Kevin's supervisor, Jill, has asked for an update on today's sales, Jill is pretty busy moving back and forth between different store locations. How can Kevin most effectively deliver an update to her ? a) Call with a quick update Ob ) Send a detailed text message c ) Book a one-hour meeting for tomorrow morning d) Send a detailed email
Answer:
d
Explanation:
since it is much convenient since the email will not get lost and it's contents will not be forgotten
which of the following measurements is equivalent to 5.461x10^-7m?
Answer:
B. 0.0000005461m
I used the method of moving the decimal.
5. For Sodium, the Work Function is listed as 2.75 eV but the Ionization Energy is listed as 5.14 eV. Is one of the experiments wrong? Give a possible explanation as to this difference in the minimum energy needed to eject or free an electron from Sodium.
Answer:
See explanation
Explanation:
The work function of a metal is defined as that minimum energy which is required to remove one electron from the surface of a metal when it is irradiated with a photon of light. The work function is different for different metals.
The ionization energy of a metal is the energy required to remove an electron from an atom. It depends on the position of the electron within the atom.
The work function specifically refers to the energy required to remove an electron from the conduction band of a metal. Hence, the work function is always lower than the ionization energy.
The Ka for acetic acid (HC2H3O2) is 1.80 x 10-5 . Determine the pH of a 0.0500mol/L acetic acid solution.
I have no idea how to approach this, so If you have the answer for it, please respond as soon as you can
Answer:
pH = 3.02
Explanation:
Acetic Acid is a weak acid (HOAc) that ionizes only ~1.5% as follows:
HOAc ⇄ H⁺ + OAc⁻.
In pure water the hydronium ion concentration [H⁺] equals the acetate ion concentration [OAc⁻] and can be determined* using the formula [H⁺] = [OAc⁻] = SqrRt(Ka·[acid]) = SqrRt(1.8x10⁻⁵ x 0.0500)M = 9.5x10⁻⁴M.
By definition, pH = -log[H⁺] = -log(9.5x10⁻⁴) = 3.02
______________________________________________________
*This formula can be used to determine the [H⁺] & [Anion⁻] concentrations for any weak acid in pure water given its Ka-value and the molar concentration of acid in solution.
The half-life of radon-222 is 3.8 days. How many grams of radon-222 remain
after 15.2 days if the original amount was 6.00 g?
A. 0.750 g
B. 0.375 g
C. 1.20 g
D. 3.00 g
The mass of radon-222 that will remain after 15.2 days given that it was originally 6 g is 0.375 g (Option B)
What is half life?This is the time taken for half a substance to decay.
How to determine the number of half-lives that has elapsedWe'll begin our calculation by calculating the number of half-lives that has elapsed after 15.2 days. This is illustrated below:
Half-life (t½) = 3.8 daysTime (t) = 15.2 day Number of half-lives (n) =?n = t / t½
n = 15.2 / 3.8
n = 4
Thus, 4 half-lives has elapsed.
How to determine the amount remainingOriginal amount (N₀) = 6 gNumber of half-lives (n) = 4Amount remaining (N) = ?The amount of radon-222 remaining can be obtained as illustrated below:
N = N₀ / 2ⁿ
N = 6 / 2⁴
N = 6 / 16
N = 0.375 g
Thus, the amount of radon-222 remaining after 15.2 days is 0.375 g
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Suppose a 0.034 M aqueous solution of sulfuric acid (H2SO4) is prepared. Calculate the equilibrium molarity of SO4 You'll find information on the properties of sulfuric acid in the ALEKS Data resource. Round your answer to 2 significant digits.
Answer:
[SO4²⁻] = 0.015M
Explanation:
When H2SO4 is dissolved in water, HSO4- is produced in a direct reaction as follows:
H2SO4 → HSO4- + H+
As 1 mole of H2SO4 produce 1 mole of HSO4-, the molarity of HSO4- in this first reaction is 0.034M
Now, the HSO4- is in equilibrium with SO42- and H+ as follows:
HSO4⁻ ⇄ SO4²⁻ + H⁺
Where the equilibrium constant, K, is defined as:
K = 1.2x10⁻² = [SO4²⁻] [H⁺] / [HSO4⁻]
Where [] are the equilibrium concentrations of each species in the reaction.
The equilibrium concentrations are:
[SO4²⁻] = X
[H⁺] = X
[HSO4⁻] = 0.034M - X
Where X is reaction coordinate
Replacing:
1.2x10⁻² = [X] [X] / [0.034-X]
4.08x10⁻⁴ - 1.2x10⁻²X = X²
4.08x10⁻⁴ - 1.2x10⁻²X - X² = 0
Solving for X:
X = -0.027M. False solution, there are no negative concentrations.
X = 0.015M. Right solution.
That means the equilibrium molarity of SO4²⁻,
[SO4²⁻] = X
[SO4²⁻] = 0.015MGM 2 all ,What is an atom define it .Good Day
Answer:
An atom is the smallest particle of an element that can take part in chemical reaction.
Explanation:
hope it will help u Amri
The reaction A + B <-------> C + D has been studied at five widely different temperature and the equilibrium tabulated.
Equilibrium constant K (at varies temperatures)
K at T1 1 x 10^-2
K at T2 2.25
K at T3 1.0
K at T4 81
K at T5 4 x 10^1
Which temperature is the products favored?
If K is greater than 1, then products are favored
What volume of a 1.5 M KOH solution is needed to provide 3.0 moles of KOH?
3.0 L
2.0 L
4.5 L
0.50 L
0.22 L
Please explain!
Explanation:
here's the answer to your question
2.0 L
Answer:
Solution given:
no. of mole(n)=3.0mole
molarity(M)=1.5M
we have
Volume of a substance is equal to the ratio of its no of mole to its molarity.
By this we get a relation:
Volume=no.of mole/molarity
substituting value
Volume=3.0/1.5=2
The required volume is 2 litre.
How many moles of NiCl2 can be formed in the reaction of 7.00 mol of Ni and 14.0 mol of HCl?
Answer:
since the concentration of limiting reactant are the same for both nickel and hydrochloric acid, they both will produce the same amount if Nickel Chloride
7 mols of [tex]NiCl_2[/tex] formed in a reaction of 7 mol of Ni and 14 mol of HCl.
The moles of Ni = 7 mol
The mols of HCl = 14 mol
It is required to calculate moles of [tex]NiCl_2[/tex]
What is a mole?A mole corresponds to the mass of a substance that contains [tex]6.023 \times 10^{23}[/tex]particles of the substance. The mole is the SI unit for the amount of a substance. Its symbol is mol.
The reaction of Ni and HCl occurs as
[tex]Ni +2 HCl \to NiCl_2 + H_2[/tex]
Since the concentration of limiting reactant are the same for both nickel and hydrochloric acid, they both will produce the same amount of Nickel Chloride.
If we have 7 mols of Ni and 14 mols of HCl, then when the 7 moles of Ni has reacted, we will still have 7 moles of HCl unreacted.
So, the moles of [tex]NiCl_2[/tex] formed equal to the moles of Ni and HCl reacted.
Therefore, 7 mols of [tex]NiCl_2[/tex] formed in a reaction of 7 mol of Ni and 14 mol of HCl.
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Adding more than one equivalent of HCl to pent-1-yne will lead to which product:______.
a. 1,2-dichloro-1-butene.
b. 1,1-dichloropentane.
c. 2,2-dichloropentane.
d. 2,2-dichlorobutane.
Answer:
c. 2,2-dichloropentane.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to firstly draw the structure of the reactant, pent-1-yne:
[tex]CH\equiv C-CH_2-CH_2-CH_2[/tex]
Now, we infer the halogen is added to the carbon atom with the most carbon atoms next to it, in this case, carbon #2, in order to write the following product:
[tex]CH\equiv C-CH_2-CH_2-CH_2+2HCl\rightarrow CH_3- CCl_2-CH_2-CH_2-CH_2[/tex]
Whose name is 2,2-dichloropentane.
Regards!
If we slowly add a solution of mercury(II) ions to a solution of aqueous halide ions with roughly equal concentrations, a precipitate will form. Explain what the precipitate will consist of initially. g
Water, mercury chloride and nitrogen oxide.
Water, mercury chloride and nitrogen oxide will present in the precipitate when we slowly add a solution of mercury(II) nitrate to a solution of aqueous hydrochloric acid having halide ions both in equal concentrations. The equation of this reaction is Hg2(NO3)2 + 4 HCl ----> 2 HgCl2 + 2 H2O + 2 NO so it is concluded that from this reaction we get precipitate of water, mercury chloride and nitrogen oxide.
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Why does nitrogen not show allotropy?
Answer:
Nitrogen does not show allotropy because of its small size and high electronegativity. The single N-N bond is weaker than P-P bond because of high inter electronic repulsions among non-bonding electrons due to the small bond distance. Hence it does not show allotropy.
Answer:
The nitrogen atom has short inter-bond distance, hence highly electronegative in terms of magnitude. This creates no relation in energy varieties hence no allotropes formed.
Nitrogen atom is also very small.
Determine the highest level of protein structure described by each item.
a. Primary structure
b. Secondary structure
c. Tertiary structure
d. Quaternary structure
1. order of amino acids
2. overall macromolecule structure containing more than one polypeptide chain
From each of the protein structures listed, the option with the highest level of protein structure as regards with order of amino acids and overall macromolecule structure is quaternary structure. That is option D.
The protein one of the essential nutrients that is found in and consumed by mammals.
There are different types of proteins and their functions depends on their shape, structure or conformation.
The structure of proteins include:
Primary structure: This is the simplest shape of proteins. This is because, the amino acids of a polypeptide is arranged in a linear form.Secondary structure: This is the local folded structures that form within a polypeptide due to interactions between atoms of the backbone.Tertiary structure: These are three dimensional structures of proteins that occurs as a result of the interactions between the R groups of the amino acids that make up the protein.Quaternary structure: This protein structure contains multiple polypeptide chains also called subunits.Therefore, the option with the highest level of protein structure as regards with order of amino acids and overall macromolecule structure is quaternary structure.
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Which of the following statements is correct concerning the class of reactions to be expected for benzene and cyclooctatetraene?
A) Both substances undergo addition reactions.
B) Both substances undergo substitution reactions.
C) Benzene undergoes addition; cyclooctatetraene undergoes substitution.
D) Benzene undergoes substitution; cyclooctatetraene undergoes addition.
Answer:
Both substances undergo substitution reactions.
Explanation:
Let us go back to the idea of aromaticity. Aromatic substances are said to possess (4n + 2) π electrons according to Huckel rule.
Aromatic substances are unusually stable and the aromatic ring can not be destroyed by addition reactions.
Since both benzene and cyclooctatetraene are both aromatic, they do not undergo addition reactions whereby the aromatic ring is destroyed. They both undergo substitution reaction in which the aromatic ring is maintained.
