Questions tagged [homework]
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173
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How to estimate the concentration of OH that comes from just the autoprolysis of water in a basic solution?
In my analytical chemistry course, a question reads:
What is the pH of a 0.10 M solution of THAM? Is it valid to neglect the autoprotolysis of water? Justify and explain your answer by estimating ...
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2
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Reactions of ketones and aldehydes
Our topic was about ketones and aldehydes (carbonyl group) including hemiketals and hemiacetals and he asked us to do a homework. I cannot find an answer to this one.Please explain me the reaction and ...
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Volume change inside a balloon upon decreasing the the outer pressure
A balloon is filled with hydrogen at room temperature. It will burst
if pressure exceeds 0.2 bar. If at 1 bar pressure the gas occupies
2.27 L volume, upto what volume can the balloon be expanded?
...
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303
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What happens to the shielding of the proton when an alcohol is oxidized?
The full question:
For H-NMR, the magnetic field experienced by a hydrogen atom can be
externally applied or internally induced or some combination of the
two. When the applied and induced ...
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683
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Determine moles of limiting reagent
In the reaction involving 0.1 g of calcium nitrate and 1.5 g of sodium phosphate, what is the number of moles of the limiting reagent?
Here is what I have so far:
Balanced equation:
$$\ce{3Ca(NO3)2 +...
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900
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The temperature rise after neutralisation
The answer to this question is B, however, I don't quite understand.
If considering Q= mc delta T, the heat released is to some extent being influenced by the no. of moles. If using that line of ...
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What is the correct order of chemical reactivity in terms of oxidising property for the following elements: F, Cl, O, and N
This is a textbook question. I am confused as to which factors i should consider while sorting out these elements. If I take electron gain enthalpy, then Cl should be greater than F, but if i consider ...
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Perovskite reaction equation (KMnF3)
For the synthesis of $\ce{KMnF3}$ I said the reaction equation was
$\ce{3KF + MnCl2 -> KMnF3 + 2KCl}$
Is it this simple or are am I missing something with these particular types of reactions?
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Explain the difference in stability of permanganate ions in acidic/ alkaline solutions?
The question is such:
Use the data to comment on the stability of $\ce{MnO4-}$ in acidic and basic solution. Suggest a reason for this difference.
$$\begin{align}
&\text{acidic solution:}&...
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How do I figure out the amount of water (mL) and amount of Aluminum (g)?
We have a project where we have to extract copper from copper sulfate. But my group is given a powder version ($5~\mathrm{g}$), so we have to first dilute it with water and then combine it with ...
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How to convert an oxirane to an alkanol with one additional carbon atom?
This is a question given in our exam.
In the reaction,
Find the reagents X and Y required for steps(ii) and (iii) are _______ and ________ respectively.
I have tried in this way but I have stuck in ...
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What is the effect of adding HCl on a certain solution at equilibrium?
If we have
$$\ce{CH3COOH + H2O <=> CH3COO- + H+}$$
what is the effect on acetate ions when adding each HCl and NaOH to the solution? (State why according to Le Chatelier's principle)
Le ...
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Understanding Standard Hydrogen Electrode
I came across a question today.
A galvanic cell is composed of two hydrogen electrodes, one of which is a standard one. In which of the following solutions should the other electrode be immersed to ...
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127
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Energy levels transitions of an electron?
I have an example that tells me that the energy transition between $n=1$ and $n=3$ is $12.1\ \mathrm{eV}$ using the following formula:
$$E= -RH (\frac{1}{m^2} - \frac{1}{n^2})$$
and that the ...
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142
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Calculate the heat of a reaction
Say I would like to calculate the heat produced by the following reaction:
$$\ce{2SO2 + O2\longrightarrow2SO3}$$
I have calculated the moles of the reagents. I can't seem to figure out how to ...
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How to determine the products of a redox reaction
I'm doing a paper on water treatment methods, and in one section, I'm describing how a nearby water treatment plant is removing Trichloroethylene ($\ce{C2HCl3}$) from water by oxidizing it using Ozone ...
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Which statement is correct about electron orbitals and energy levels?
Which statement is correct about electron orbitals and energy levels?
A. Yttrium, $\ce{Y}$ ($Z = 39$) is the first element in the periodic table with an electron in a f sub-level.
B. The maximum ...
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What is the chemical redox equation between hydrogen peroxide and melanin?
I am investigating hair bleach, and want to figure out the redox reaction between $\ce{H2O2}$ (hydrogen peroxide) and $\ce{C18H10N2O4}$ (melanin). $\ce{H2O2}$ is a strong oxidizing agent in this redox ...
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201
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What is the velocity of an ejected electron in lithium when subjected to UV radiation?
If UV radiation strikes an atom of lithium with one electron in its lowest allowed energy state with enough energy to eject the electron from orbit, what is the electron's velocity upon ejection? The ...
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313
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Precipitation with NaI
I dissolved $\ce{[Pt(NH3)4](NO3)2}$ in water then I added small amount of $\ce{NaI}$ ($1~\mathrm{M}$) to it. Precipitation occurred. I want to know what happened?
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219
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How to calculate concentrations and what is the concept of 'mole'?
Say I have a $50~\mathrm{ml}$ solution of a liquid mixture which is $30~\%$ concentrated. Now if I take $20~\mathrm{ml}$ of that liquid out from that mix, what would be the resulting concentration of ...
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Transition Metal Compounds [closed]
So I have a few dumb questions. I'm still in high school and am doing something on magnetic properties of transition metals. I'm facing a few roadblocks.
1) What're compounds like $\ce{CoBr2, CoCl2, ...
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146
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Dilution with 3 Different Percentages
I'm trying to solve this problem.
How many grams of a solution at $25\%$ do you have to add to $100\ \mathrm{g}$ of a solution at $40\%$ to obtain a solution at $30\%$.
My Attempt
It's a bit ...
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Mr of Acid getting wrong answer
I am preparing for A level chemistry exams. One of the questions I came across is
Calculate the $M_\mathrm r$ of unknown monoprotic acid. The volume is $15\,\rm cm^3$ and concentration $10.95\,\rm ...
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What is the mass fraction of C2HCl3 in the liquid phase?
Vapour-liquid equilibrium of a two-component ideal solution of trichloroethene (C2HCl3) and trichloromethane (CHCl3) is established at 25 °C. The mole fraction of CHCl3 in the vapour phase is 1. What ...
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790
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TLC plate and Rf values
I have calculated the Rf values for 6 samples. How do I determine which is really Sriracha ?
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How to calculate the volume of a 0.1 M NaOH(aq) solution necessary to make a 0.5 M EDTA solution with pH = 8?
I was told that EDTA dissolves at a pH of $8$. Therefore I need to use a base to increase the pH to $8$ is what I understand. How exactly would I go about this?
In my head I if I wanted $1~\mathrm{L}...
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Does PO3- exist as a free ion or in a cyclic/linear polymeric form? [closed]
My book says that $\ce{PO3-}$ exists as cyclic or linear polymeric structure but doesn't elaborate on this. I Googled this and found no result either.
Also, what would be the structure of $\ce{PO3-}$...
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Thermochemistry Problem - How did they get that volume?
The chemistry problem in my textbook is : Calculate the work one when 2.0 L of methane gas, $\ce{CH4}$ (g) undergoes combustion in excess oxygen at 0ºC and 1.00 bar. Assume the volume of water formed ...
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Finding the mass of NaNO3 in original mixture from preciptate
A 1.61-g sample of a mixture of $\ce{AgNO3}$ and $\ce{NaNO3}$ is treated with excess $\ce{Na2S}\:(\mathrm{aq})$. The precipitate is filtered off, dried and weighed. The dried precipitate weighs 0.44 g....
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Determine the mole fraction
Under certain conditions, the well-known fertilizer $\ce{NH4NO3 (s)}$ explodes according to the following balanced reaction:
$\ce{2NH4NO3 (s) -> 2N2 (g) + 4H2O (g) + O2 (g)}$
Exactly 8 g of $\ce{...
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How high in (mmH2O) is the column of water in the tube?
A long glass tube, sealed at one end, has an inner diameter of 23.4 mm. The tube is filled with water and inverted into a pail of water. If the atmospheric pressure is 735 mmHg, how high (in mmH2O) is ...
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Getting the molality of a solution given molarity and density
If a solution of $\ce{HNO3}$ has a molarity of 16 and a density of
$1.42\ \rm{g/mL}$, what is the molality of the solution?
Well, a molarity of 16 means that there are 16 moles of solute for every ...
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372
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Using gas laws to find density
An unknown gas at $\mathrm{63.1\ ^\circ C}$ and $\mathrm{1.05\ atm}$ has a molar mass of $\mathrm{16.04\ g/mol}$.
What is the density of the gas?
I know I need to use the $pV=nRT$ equation but it ...
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Original concentration calculation homework
A student performs the following gravimetric analysis of iron ions in a water system
$$\ce{Fe^2+ (aq) + CO3^2- (aq) <=> FeCO3 (s)}$$
If this student used excess carbonate and obtained the ...
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How does valency change in a reaction?
There is a reaction given in my book:
$\ce{2FeSO_4 +Heat -> Fe_2O_3 + SO_2 + SO_3}$
I just noticed that on the left $\ce{Fe}$ has valency $2$, while it has $3$ on the right. How can it change ...
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578
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Which of the following have the same molecular formula as the molecule shown in the model?
This model has 3 hydrogens connected the the first and last carbon and 2 hydrogens connected to the other carbons
Finding the same molecular formula as the alkane model I have to check all that apply ...
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133
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Hydrolysis of Radiolabeled Esters
Hydrolysis of C$_6$H$_5$COO$^{18}$CH$_3$ with aqueous NaOH produces what final product.
(a) CH$_3$$^{18}$OH
(b) CH$_3$CO$^{18}$ONa
(c) CH$_3$C$^{18}$OONa
(d) CH$_3$$^{18}$ONa
(e) CH$_3$OH
The ...
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How to calculate concentrations in a diluted mixture of multiple solutions?
I have a homework problem as follows:
A solution was prepared by mixing $25.0\ \mathrm{mL}$ of $0.208\ \mathrm{M}$ $\ce{Fe(NO3)3}$ and $4.50\ \mathrm{mL}$ of $0.00190\ \mathrm{M}$ $\ce{KSCN}$ and ...
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Convert grams of water to steam
I'm working through problems in my textbook. How much heat is required to convert 2.55 g of $\ce{H2O}$ at 28 °C to steam at 100 °C?
In simpler problems I've used the fact that $\Delta H_\text{fus} = ...
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What are all the stereoisomers of 1-ethyl-3-methylcyclohexane?
What are all the stereoisomers of 1-ethyl-3-methylcyclohexane? The following image shows my attempt to answer the question. But I am not sure if I am correct.
Note: I am treating this cyclohexane as ...
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How to convert ethanal to 2-hydroxy-3 butenoic acid?
How to convert ethanal to 2-hydroxy-3 butenoic acid?
I tried crossed aldol condensation with formaldehyde followed by acid addition.After that how should I proceed ?
user14857
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Identification of solutions by solubility when mixed with each other
$\ce{Pb^{2+} (aq), Cl- (aq), Ag+ (aq), (SO4)^{2-} (aq)}$. You number the four bottles, 1,2,3,4and while numbering them, you notice that bottles 1 and 3 have the word "cation" on their lids while ...
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Reaction of 1,1-diphenylethanol on Montmorillonite K10 under microwave radiation
What is the product of 1,1-diphenylethanol + Montmorillonite K10 Clay undergoing microwave radiation? What is the mechanism for it?
My effort:
1,1-diphenylethanol + Montmorillonite K10 Clay catalyst ...
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2
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3k
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Temperature Dependent Specific Heat of Nitrogen
Calculate the change in enthalpy as 1kg of nitrogen is heated from 1000K to 1500K, assuming the nitrogen is an ideal gas at a constant pressure. The tempreature dependent specific heat of nitrogen is ...
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161
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The difference between the different types of rhodamine
What is the difference between different type of rhodamine, for example rhodamine red and rhodamine green?
are these two type of rhodamine (red & green) have a good Raman signal?
We would like ...
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638
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For the half reaction HSO3- -> S2O6^2- why is it that 2e- are on the right hand side when balancing and not one electron?
$$\ce{HSO3- -> S2O6^2-}$$
The oxidation number of $\ce{S}$ on the left is +4 and +5 so when adding electrons to balance the oxidation number why is $\ce{2e-}$ added to the right instead of one?
...
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Why/How am I calculating freezing point depression wrong?
What is the freezing point of water made by dissolving $\mathrm{10.11~g}$ of magnesium chloride in $\mathrm{86.03~g}$ of water?
The freezing-point depression constant of water is $\mathrm{1.86~^\...
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Titration of C₄H₆O₂
$\ce{C4H6O2}$ (10.75 g) was dissolved in water (250 cm3) and then a 20 cm3 sample was titrated against an alkali metal hydroxide solution. This required 17.35 cm3 of the alkali. What was the ...
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How to write equations for dissociation of ionic compounds in water?
Please write a dissociation-in-water equation for the compounds $\ce{BeI2}$ and $\ce{LiI}$. Make sure to add the states of matter after each compound.
Currently, for $\ce{BeI2}$ I have the equation $$...
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