If your question is part of your high school or college/university homework, please use this tag. It signifies that instead of a direct answer, care should be taken to explaining the steps to the solution, preferably sticking to just giving helpful, conceptual hints. This tag may be applied to ...

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-1
votes
0answers
11 views

Detection of foreign elements using Ca or K instead of Na [on hold]

Is it possible to use calcium or potassium in place of sodium in detection of foreign elements? Please add you approach here.
-2
votes
0answers
40 views

Assigning Oxidation Numbers to Different Compounds [on hold]

The homework system is telling me I got the question worng with the numbers listed below: Oxidation Numbers Use the rules (in order) to assign oxidation numbers to each of the elements in the ...
-3
votes
0answers
27 views

Determine the molarity of a HCl solution by titration with NaOH [on hold]

To titrate $15.00~\mathrm{mL}$ of an unknown HCl sample, use $25.00~\mathrm{mL}$ of a standard $0.2~\mathrm{M}$ NaOH titrant. What was the Molarity of the HCl solution?
0
votes
0answers
21 views

Tell the cases in which stirring causes delay instead of increasing the reaction rate? [on hold]

Tell the cases in which stirring causes delay instead of increasing the reaction rate? Assume both the reactants in liquid or gas state.
0
votes
1answer
36 views

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 ...
0
votes
0answers
20 views

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 ?
-3
votes
0answers
20 views

Mixed Gaseous Solvent Question [on hold]

Part A: At what temperature does the following solution start to boil? Propane 26% Iso-Butane 28% N-Butane 45% Part B: Design a solution that contains only Propane and N-Butane ...
5
votes
0answers
31 views

Belousov-Zhabotinsky reaction: questions about rate determining step, k and activation energy

In one of our lab courses, we performed a variation of the BZ reaction, the experimental procedure is outlined below: Experimental Procedure 10 mL of 3.0 M $\ce{H2SO4}$ was added to test tube T1. ...
-1
votes
0answers
17 views

The ideal gas law [on hold]

Figure out the volume of $\ce{O2}$ gas produced at 700 torr and 27 degrees C from decomposition of 25 grams of $\ce{KCIO3}$ First of all I can't calculate the number of moles of $\ce{O2}$ produced, ...
1
vote
0answers
31 views

How can I predict the product of the reaction of a substituted tetrahydrofuran with HI?

Well, this looks like a pretty straight forward question. But I am getting stuck at the point when preference is being given to the less stable 1° carbocation to form the product. Or am I writing an ...
-2
votes
0answers
19 views

Acid & base catalysed hydrolysis of aldehydes and ketones? [on hold]

Reaction mechanisms for hydrolysis of aldehydes and ketones? Our teacher at school didn't explain the mechanism and I really need it in order to understand it correctly.
0
votes
0answers
20 views

Determining Enthalpy of reactions using different reactions

So I've been stuck on this question for a while regarding enthalpy changes. I can't seem to figure it out as I've been trying for hours. Here's the question: Instructions: In this activity, calculate ...
3
votes
0answers
29 views

SN1 reactivity order

The question is to compare the SN1 reactivity for the following compounds. According to me it should be like R>S>Q>P. But the correct answer is Q>P>R>S. How can a lone pair donating into a vacant p ...
0
votes
0answers
25 views

Solutes, solutions, stoichiometry [closed]

Could anyone figure out these questions for me? 87c and 101? I have not been able to figure these out. Any help would be welcome. I know I have to use the M = mol/L and stoichiometry to find ...
5
votes
0answers
36 views

A question on phlorizin

I work in a winery and we have some problems about a new process involving phlorizin. We know that phlorizin is the major dihydrochalcone found in apples, but I have been reading that this compound is ...
0
votes
1answer
19 views

Nitrogen and an unknown gas is leaked into a common vessel… The gaseous mixture contains 0.4 moles of nitrogen. Molecular mass of the other gas is?

For 10 minutes each, from two identical holes, nitrogen and an unknown gas is leaked into a common vessel of 3L capacity at 300K. The resulting pressure is 4.15 bar. If the gaseous mixture contains ...
4
votes
1answer
94 views

How does molecular collision excites the electron?

I have this question for a long time that in LASER when we do the pumping by heating how does molecular collision causes the atoms(molecules) to reach in excited state. E.g. in $\ce{He-Ne}$ laser when ...
-1
votes
1answer
29 views

Matter on Mole Concept [closed]

A solution is prepared by dissolving $16.0\ \mathrm{g}$ of calcium chloride, $\ce{CaCl2}$ in $64.0\ \mathrm{g}$ of water. The solution formed has a density of $1.18\ \mathrm{g\ mL^{-1}}$. Calculate ...
0
votes
1answer
36 views

Proton NMR Ratios [closed]

Question: Analysis by NMR during a reaction can be difficult because of the number of molecules present. If a small aliquot of the reaction mixture in this experiment were taken and added to ...
0
votes
0answers
29 views

How to calculate the osmotic pressure given the vapour pressure of a solution?

The vapour pressure of water at $293~\mathrm{K}$ is $2438~\mathrm{Pa}$ and the vapour pressure of an aqueous solution is $2395.8~\mathrm{Pa}$. If the solution density is $1080~\mathrm{kg/m^3}$ at ...
-1
votes
0answers
15 views

mass of magnesium when reacting with acid [closed]

What is the mass of magnesium which completely reacts with $250~\mathrm{cm^3}$ of $1.0~\mathrm{mol/dm^3}$ sulfuric acid?
-1
votes
0answers
26 views

Titration of phenol with sodium hydroxide [closed]

Phenol, $\ce{C5H5OH}$ is a weak acid with $K_a = 1.0 \times 10^{-10}$ at 25C. If 15.0 mL of 0.20 mol/L aqueous phenol solution is titrated with 0.20 mol/L $\ce{NaOH(aq)}$ determine the pH of the ...
0
votes
0answers
19 views

Freezing point of multiple solute solution

I have 4 solutes, iron, sulfate, sulfuric acid, and peroxide. This is diluted in water and I have the molalities in mol/kg ($0.5, 0.1, 0.4, 0.35$). I tried using $\Delta T_f=−K_f\times m$, where m is ...
2
votes
1answer
48 views

Calculating enthalpy per gram mole of oxygen bond in haemoglobin

A solution of $5\ \mathrm{g}$ of haemoglobin in $100\ \mathrm{cm^3}$ of solution shows a temperature raise of $0.031\ \mathrm{^\circ C}$ for complete oxygenation. Each mole of haemoglobin binds $4\ ...
4
votes
1answer
34 views

Correctness of writing H3C as opposed to CH3 in a carbon chain

I have been studying alkanes, alkenes & alkenes for a while, and I see in the examples that all the basic structural formulas start with CH3 then CH2 and the last carbon atom is CH3 but the one ...
3
votes
1answer
38 views

How to find the volume of CO2 formed in the reaction, given volume?

$60\ \mathrm{cm^3}$ of oxygen was added to $10\ \mathrm{cm^3}$ of a gaseous unsaturated hydrocarbon. After explosion and cooling to room temperature, the residual gaseous occupied $45\ \mathrm{cm^3}$. ...
2
votes
1answer
44 views

How is the oxide of iron: Fe3O4 possible?

If oxygen has a valency of 2-, 4 of it would result in 8-. But iron doesn't have a (variable) valency of anything that goes to 8-. How is $\ce{Fe3O4}$ possible?
0
votes
0answers
32 views

How do you determine stable oxidation from Ionization energy

Question: You have been given the first, second and third ionization energies of an element as 7eV, 12.5eV and 42.5eV, respectively. How do you find the most stable oxidation state (or charge on the ...
1
vote
1answer
42 views

What fraction of air does elapse upon heating an empty flask?

A student forgot to add the reaction mixture to the round bottomed flask at 27 °C but instead he placed the flask on the flame. After a lapse of time he realised his mistake and using a pyrometer ...
3
votes
1answer
21 views

Why does hydrogen phosphate act as a base?

Let's look at question c So, I'm a bit confused with what's happening. It seems that water is acting as an acid in this reaction, and donating protons to the ion. Can someone just elaborate on this ...
3
votes
0answers
43 views

How can nitrogen achieve +5 oxidation state?

Nitrogen has no available d-orbitals. Yet, it forms compounds where its oxidation state is +5, like in nitric acid. How?
-1
votes
0answers
18 views

Mole fraction of the solvent related to vapor pressure [on hold]

The vapour pressure of a solvent decreased by 10 mmHg when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of ...
0
votes
1answer
19 views

Find oxidation number of a metal in a compound

Calculate the oxidation number of $\ce{Fe}$ in $\ce{Fe2O3}$. Alright. So we have a metal and an non metal. This means that iron will lose electrons and give them to oxygen. So it will be a ...
3
votes
0answers
40 views

How can I tell if a molecule is polar or not? [duplicate]

Consider $$\ce{PCl3}\\ \ce{CH2Cl2}\\ \ce{HCN}\\ \ce{SiO2}$$ Which ones are polar substances? I appear to be lacking on the concept of "polar substance". I was just studying about Lewis ...
2
votes
1answer
12 views

Get the molar mass of a polymer in a mixture given its osmotic pressure

Have a dissolution with $12$g of an unknown polymer for each liter of solution at $25^\text{o}$C has an osmotic pressure of $12.1$ torr. What is the molar mass of the polymer? Apparently the formula ...
3
votes
0answers
20 views

Lemieux-Johnson oxidation on cycles

Consider the following molecule : What would it yield by a Lemieux-Johonson oxydation ($\ce{OsO_4,NaIO_4}$) ? My first guess would have been that $\ce{OsO_4}$ was likely to attack any of the bonds ...
8
votes
2answers
286 views

Getting 3,4-dimethylhex-3-ene from but-2-ene

How can one get 3,4-dimethylhex-3-ene from but-2-ene ? $\hskip2in$ Using $\ce{Br_2}$ then two equivalents of $\ce{CH_3CH_2MgBr}$, I can get the corresponding alkane (3,4-dimethylhexane) but I don't ...
1
vote
2answers
39 views

Get the molar fraction of a mixture component given only its pressure

You have a mixture of $\ce{He, Ne, Ar}$ gases with a total pressure of $8.40$ atmospheres. $\ce{He}$ has a pressure of $1.50$ and $\ce{Ne}$ has $2.00$. What is the molar fraction of $\ce{Ar}$? ...
2
votes
1answer
27 views

Find number grams of the solute in a dissolution given its density and Molarity

Have a dissolution of $\ce{HNO_3}$ in water. The density is $1.42\ce{g/mL}$ with a concentration of $\ce{16M}$. What is the concentration in % mass/mass? Alright. So the % mass/mass is ...
0
votes
1answer
40 views

Is there any reaction between amines and AgNO3?

I found a question in a book about the reaction between $\ce{AgNO3}$ and aromatic/aliphatic amines, but I couldn't find any information about it.
0
votes
0answers
25 views

Calculate ΔH∘rxn for this reaction using standard enthalpies of formation

Propane ($\ce{C3H8}$) burns according to the following balanced equation: $\ce{C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(g)}$ The standard enthalpy of formation of gaseous propane is ...
2
votes
3answers
72 views

How to know the formula of different compounds?

For example, if I didn't know the compound tin chloride, and I was asked to write out its formula, how would I know how to? Because it seems unreasonable to know the formula of every compound in ...
0
votes
0answers
33 views

At 10 C, a small piece of Zn reacts with 2.0 M HCl to produce 15.0 mL of H2 gas in 25 s. What is the rate of the reaction?

At $10~^{\circ}\mathrm{C}$, a small piece of $\ce{Zn}$ reacts with $\mathrm{2.0~M}$ $\ce{HCl}$ to produce 15.0 mL of $\ce{H2}$ gas in 25 s. What is the rate of the reaction? Please show how to ...
0
votes
1answer
33 views

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 ...
0
votes
0answers
16 views

Determination of AFR with Fuel Oil Analysis and given Excess Air

Fuel Oil has the following Analysis: C = 89% H2 = 8% N2 = 2% S = 1% With 3% Excess Air, what is the actual amount of air needed to burn the fuel oil? Answer is 14.17 So I try the Formula for ...
2
votes
0answers
20 views

Thickness of oxide coating through anodising - voltage dependence?

In titanium anodising, solid titanium reacts with the oxygen formed at it's surface (to form titanium (IV) oxide or $\ce{TiO2}$) through the electrolysis of water. Experimentation and research has ...
0
votes
0answers
84 views

What is the product of 1,1-diphenylethanol + Montmorillonite K10 Clay undergoing microwave radiation? What is the mechanism for it?

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 ...
1
vote
1answer
57 views

How can glycine act as a buffer at pH 6.00 and why?

How can glycine act as a buffer at pH 6.00 and why? Please use chemical equations to show how it can act as a buffer at this pH specifically? my work At the pH 6.00 glycine act as a buffer ...
0
votes
1answer
41 views

What is the final temperature of each substance upon absorbing 2.25 kJ of heat?

Suppose that 28 g of each of the following substances is initially at 29.0 °C. What is the final temperature of each substance upon absorbing 2.25 kJ of heat? Part B) Silver My work: $2250 = ...
0
votes
0answers
12 views

Absorbance of dpph test for antioxidant activity

What is the range absorbance for essential oil sample in dpph test (antioxidant activity)? My absorbance was 1.322. And the inhibition concentration was 21.121. My control absorbance was 1.676. Is ...