Questions tagged [homework]

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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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0answers
765 views

Precipitation of citric acid by CaCl2 and Ca(OH)2? [closed]

I need to precipitate citric acid from an aqueous solution in the form of calcium citrate. There are, to my knowledge, two different methods of doing this: using $\ce{CaCl2}$ and which will react ...
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0answers
319 views

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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3answers
12k views

How do I calculate the pressure of a known liquid in a sealed container heated above boiling point?

If I have water in a sealed container heated to say 150 degrees, how do I determine the amount of pressure being generated in the container? What about for other liquids? I have searched extensively ...
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1answer
303 views

Is 2,3-dimethylprop-1-ene a possible organic structure?

Is 2,3-dimethylprop-1-ene a possible organic structure? I am not sure how to approach this, what would the correct name of this molecule be?
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2answers
1k views

When finding hybridisation of atoms, why are double bonds and triple bonds only considered once?

To figure out what hybridization an atom has is to just count the number of atoms bonded to it and the number of lone pairs. Double and triple bonds still count as being only bonded to one atom. (...
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2answers
1k views

How can I derive whether the methyl cation or anion is planar?

According to VSEPR theory, in which species do all the atoms lie in the same plane? $\ce{CH3+}$ $\ce{CH3-}$ (A) 1 only (B) 2 only (C) both 1 and 2 (D) neither 1 nor 2 My try: ...
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1answer
18k views

When Z>1 are repulsive forces dominant or are attractive forces dominant?

According to PVreal = ZRT If z >1 repulsive forces are dominant or are attractive forces? Different teachers are telling contradictory answers and after referring a few books, I have become more ...
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2answers
3k views

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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1answer
34k views

How to tell if a molecule will participate in hydrogen bonding with water?

I was recently doing some organic chemistry work and came across a set of problems. "Which of the following compounds will participate in hydrogen bonding with water? For each compound, indicate ...
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3answers
6k views

Basicity of substituted pyridines

Which of the following pyridines are most basic? I would've considered D, since chlorine is the most electronegative, and would therefore have the largest partial negative charge, making it more ...
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2answers
117 views

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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2answers
827 views

Naming rules and acidity of Cl2CHCH2COOH

How do we name $\ce{Cl2CHCH2COOH}$ ? Is seeing branched chain our number 1 priority so we name it 1,1-dichloro-3-propanoic acid? also Which is more acidic $\ce{Cl2CHCOOH}$ or $\ce{Cl2CHCH2COOH}$ ?...
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2answers
2k views

Which of the following elements forms a water-soluble, alkaline oxide?

An element burns in oxygen to form a solid oxide which dissolves in water. The pH of the resulting solution is greater than seven. Which one of the following could the element be? A. sulphur B. ...
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1answer
3k views

Why is the water column empty in ICE table

In the ICE table pure solids and liquids have a value of one in the equilibrium expression but when we create an ICE table, why is the $\ce{H_{2}O}$ column empty? Should it not have a value of one?
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2answers
1k views

1H-NMR and deducing structures

here is the data booklet we must refer too: Here is the exam paper solution: I dont understand how they conclude this. Peak areas and the chemical shifts seem to be different for me. For example ...
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1answer
2k views

Which salt precipitates from a solution of ammonium oxalate and silver nitrate?

I am supposed to write the precipitation reaction for $\ce{(NH4)2C2O4 + AgNO3 ->[\ce{H2O}]}$ Is my equation correct? I left out the Spector ions. $$\ce{4(NH4) + 2 C2 +O4\rightarrow 4(NH4)2CO3}$$
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2answers
3k views

How will citric acid be deprotonated by pyridine?

Why do we deprotonate that specific hydrogen as opposed to any other one? What information does the table on the right give us? It seems unrelated to citric acid - where does the fluorine come from?
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2answers
5k views

Predicting electronic geometry, observable geometry, and hybridization for any atom in a molecule

Can someone please explain the intuition around the answers to this problem: I'm finding it very confusing because it seems like you have to nitpick between two resonance structures to get the ...
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2answers
45k views

How to determine which aqueous solution has the largest freezing point depression

Question This is more of a conceptual question. Let's say that we are given different aqueous solutions and we are asked to choose the one with the highest freezing point depression, which do we ...
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1answer
4k views

The mass of a carbon-12 atom is 12 amu. What percent of the mass is located in the nucleus?

The mass of a carbon-12 atom is 12 amu. What percent of the mass is located in the nucleus? and Why is the value so close to 100%?
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1answer
335 views

Interpretation of an H NMR

I am fairly new to NMR and require assistance to analyze and interpret the NMR I have provided (sorry for it being vertical). This is an unknown compound that I have derived during one of my lab ...
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2answers
24k views

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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2answers
5k views

Write a Net Ionic Equation to Represent the Reaction of Aqueous Ammonia with Propionic acid

I would like to know how do I begin to solve a problem like this? That is finding the formula equation? I would assume that it would be $$ \ce{NH3 + CH3CH2COOH -> NH3 + CH3CH2COOH + H2O} $$ I ...
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3answers
3k views

Finding the initial concentration

The solubility product of $\ce{AgBr}$ is $7.7 \cdot 10^{-13}\:\mathrm{mol^2/L^2}$. What was the initial concentration of $\ce{AgNO3}$ solution, if the precipitation of $\ce{AgBr}$ appears after the ...
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2answers
9k views

Why and how carboxylate ion has greater stability than carboxylic acid?

I found it written in my textbook. I think it's a misprint, I can't think of any logic behind this statement. I've only learned that ion is less stable specie so carboxylate ion cannot be more stable ...
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1answer
4k views

How to find the rate of effusion given rates?

Question At $25~^\circ\mathrm{C}$, a sample of $\ce{NH}$ effuses at the rate of $0.050$ moles per minute. Under the same conditions, what is the molar mass of a gas that effuses at approximately one ...
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1answer
5k views

How to round correctly when calculating the average and standard deviation?

Is my Chemistry book wrong on the significant figures in this exercise? Why did they round to 0.16 instead of 0.1580 ? Also why did they round down the means?
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1answer
311 views

Determination of initial excited state via luminescence

A one electron species initially in the some excited state ($n_i$) is irradiated with a light of wavelength 121 nm when the electron is promoted to a further higher orbit ($n_f$). In ...
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1answer
857 views

Effect of an inert gas on steam vapor pressure at equilibrium

Suppose we have a closed container with mobile walls, so it will change its volume in order to equal the external pressure(constant) to the internal pressure. This container has inside it a liquid ...
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2answers
449 views

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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1answer
438 views

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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1answer
7k views

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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1answer
4k views

How to identify the repeating unit in a polymer?

Polyvinyl acetate, PVA, is a useful adhesive for gluing together articles made from wood, paper or cardboard. The monomer of PVA is ethenyl ethanoate. PVA is formed from B by the process of ...
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2answers
7k views

How does this method of calculating the water equivalent of a calorimeter work?

I am doing a AP Chemistry lab in which we determine the heat capacity of a calorimeter (a concept that seems like it should depend on a lot more than just the calorimeter.) We have to calorimeters ...
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3answers
682 views

In order to be a gas does the pressure exerted by the gas has to be more than the atmospheric pressure?

In order to be a gas does the pressure exerted by the gas has to be more than the atmospheric pressure? Really simple, I think yes to this question but teacher says no. So what is your view into this?
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1answer
4k views

Galvanic cell using NaCl, Cu and Zn, why does it work?

Got a paper due tomorrow in chemistry, and my friends and I are totally stuck on this: Basically we mixed some regular salt (NaCl) into a glass of water and stuck a zinc nail and a copper nail into ...
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1answer
1k views

Estimating magnitude of percentage and absolute error

Can someone at least give me a hint to push me in the right direction of how to estimate the magnitude of the absolute and percentage errors when using a smaller amount in mL of a substance for a lab ...
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2answers
145 views

What is the wavelength of an electron?

The kinetic energy of an electron is $1.67 \times 10^{-17}\mathrm{J}$. Calculate the wavelength ($\lambda$) of the electron. I know the formula $\lambda= \frac{h}{mv}$; where h is Planck's constant. ...
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2answers
5k views

Calculate the second ionization energy for the Mg from the following data?

here is a problem : What I did " as shown in the picture below " I rewrote the information given in terms of reactants and products ( equations )// in Part 1 Then I used the Hess law to obtain the ...
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1answer
324 views

Equivalent Line Angle Structures?

Are the following equivalent structures for 2,2-dimethylpropane? I think so, because my rendering simply rotates the cross 45 degrees! Also, regarding 3,3-diethylpentane, are these both equally ...
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2answers
4k views

Calculating molar conductance of CaCl2

Ok, so the following question is given in my text book. Of the molar conductance value of $\ce{Ca^2+}$ and $\ce{Cl^-}$ at infinite dilution are respectively $118.88\times10^{-4}$ and $77.33\...
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1answer
15k views

How to calculate m/e value for the base peak in mass spectroscopy?

My working out: Propan-1-ol : CH3CH2CH2OH This can be broken up into: CH3 + CH2CH2OH CH3CH2 + CH2OH CH3CH2CH2 + OH Base peak = most abundant fragment formed (highest peak) How do i know which ...
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1answer
833 views

Law of Definite Proportion: Do the numbers indicating moles count?

I need to find the ratio of a substance as it converts from a bicarbonate to a carbonate: ex: $\ce{Fe(HCO3)2 -> FeCO3 + CO2 + H2O}$ $\ce{Fe(HCO3)2} / \ce{FeCO3}$ = $3/2$ *using molar masses But ...
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2answers
2k views

What is the multiplicity of this signal in the ¹H NMR of glutamine in D₂O

The 2 Hydrogens near the carbonyl (the lower 2 $\ce{H}$s are not bonded to the nitrogen) should be the most deshielded so I think they appear as the rightmost peak in the NMR. Are these 2 $\ce{H}$s a ...
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2answers
8k views

List in order of increasing radius

List in order of increasing radius: a) Rb, K, C5, Kr For this one I got C, Kr, K, Rb b) Ar, Cs, Si, Al This I got: Ar, Si, Al, Cs Does anyone know if this is correct? I don't have the solution ...
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1answer
570 views

Product/(s) of the following reaction

I was wondering what the product will be in the following reaction: $$\ce{H3COOCH3 ->[\ce{H+}]} \:?$$ I was thinking about $\ce{CH3COOH}$ being a product but I do not know the mechanism.
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1answer
160 views

Fe/Ga cell has a negative potential?

In the following homework problem, the answer says: "$E ^{o}_{cell}$ is negative, which makes the $\ce{Fe}$ and $\ce{Ga}$ half-reactions non-spontaneous." But I found $E ^{o}_{cell}$ to be positive ...
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1answer
59 views

How would you go about solving this pH problem?

What is the $\mathrm{pH}$ of a $0.24\ \mathrm M$ solution of benzylammonium chloride ($\ce{C6H5CH2NH3Cl}$)? $K_\mathrm b$ for benzylamine is $2.2\times10^{-5}$ Your answer must be within $\pm 0.4\ ...
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1answer
130 views

working with ratios and RMS to find variables

question consider separate 1.0L samples of helium and $UF_6$ both at 1.00atm and containing the same number of moles. what will the ratio of the separate temperature need to be in order to have the ...