Tagged Questions

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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2
votes
2answers
34 views

How to determine the composition for a sucrose/ zinc nitrate solution from its freezing point?

A $4~\mathrm{g}$ mixture of sucrose ($\ce{C12H22O11}$) and zinc nitrate ($\ce{Zn(NO3)2}$) is dissolved in $150~\mathrm{g}$ of water. If the resulting solution freezes at $-0.768~^\circ\mathrm{C}$, ...
-2
votes
0answers
24 views

How to determine leftover substrates in sulfur and fluorine reaction? [on hold]

If 12 moles of fluorine gas are mixed with 5 moles of sulfur, how many moles of sulfur remain after 9 moles of fluorine react? A bit confusing to solve, given the following: $$\ce{S + 3F2 -> ...
4
votes
1answer
187 views

Why is an ester more acidic than a ketone?

Every book I've read says: Esters are more acidic than ketones, because the resonance between the two oxygen atoms gives less opportunity for the delocalization of the electron pair on the alpha ...
0
votes
0answers
13 views

Calculating the heat in joules gained by a calorimeter [on hold]

25.0 ml of hot water at temp 37 degrees C was added to 25.0 ml of cold water in a "coffee-cup" calorimeter at temp 22degre C. the final temperature of the calorimeter was 28.0 degrees C. 1. Calculate ...
0
votes
0answers
26 views

Why nitrogen is inactive but oxygen is more active? [on hold]

Why is nitrogen, being the major component of the atmosphere, inactive but oxygen, the minor component, is most reactive? As per Le Chatelier's principle, if the concentration of a reactant is much ...
0
votes
1answer
33 views

Smallest whole number coefficient?

What is the smallest whole number coefficent of $\ce {Cr^{2+}}$ when the equation is balanced? $$\ce {Cr^{2+}_{(aq)} + Al_{(s)} -> Cr_{(s)} + Al^{3+}_{(aq)}}$$ I don't understand, how can this be ...
0
votes
1answer
22 views

Acid-Base Titration: Do Acids and Bases Have the Same Coefficients of Moles if They Neutralize One Another?

The questions states: Ammonia has the formula NH3. Household ammonia is a dilute aqueous solution of NH3. Aqueous ammonia is a base that can neutralize acids. If 18.2mL of 0.800 M HCl solution are ...
-1
votes
0answers
23 views

What are all isomers of alkenes excluding cyclo? [on hold]

could someone please give me a list of all isomers of alkenes from C1 to C7 excluding stereoisomers and cycloisomers?
0
votes
0answers
31 views

Application of Grahms Law of diffusion

$\ce{H2}$ (di-hydrogen) and $\ce{He}$ are kept in a container at partial pressure $p_1$ and $p_2$. A thin perforation is made in the wall of the container and it is observed that both gases diffused ...
-1
votes
0answers
13 views

Apply Hess's Law, Thermochmical equation OR q = m * C * Delta T to this reaction? [on hold]

If 0.5 grams of one element is combined with 200 milliliters of an acid (For example, Sodium(s) being put in Hydrochloric Acid) and the temperature change is recorded, then the same is done for the ...
0
votes
1answer
25 views

Finding the concentration of an ion

What is the concentration (M) of the chloride ion when 18.5 mL of a 0.622 M solution of barium chloride is combined with 15.6 mL of a 0.726 M solution of aluminum chloride? The volumes can be ...
3
votes
1answer
43 views

What does “a metallic oxide has 40% oxygen” mean?

If a metallic oxide has $40\%$ oxygen, find the equivalent weight of the metal. This amounts to finding the atomic weight of the metal and the charge on the cation (in effect identifying the ...
0
votes
0answers
13 views

about stereochemistry/major product [on hold]

Supply the correct major product formed from the following reaction link to the reaction/picture - http://i.imgur.com/9tmrS38.png
0
votes
0answers
28 views

How to balence this redox equation: Cu(NO3)2 + Al(NO3)3 -> CuO + Al2O3 + NO2 + O2? [on hold]

I am having aluminium and copper nitrates and want to dissolve them in the distilled water, and I want to know what is the (balanced equation)reaction between them! $\ce{Cu(NO3)2 + Al(NO3)3 -> ...
0
votes
1answer
39 views

Metal vs. Styrofoam cup calorimeter?

For a metal cup as opposed to a styrofoam cup calorimeter, do you expect the enthalpy of the reaction to be higher, lower, or the same? I think the enthalpy of the reaction would be the same in the ...
0
votes
1answer
23 views

Determine the Mole Ratio [on hold]

"Determine the mole ratio of moles of $\ce{H2O}$ to moles of $\ce{CoCl2}$ and the formula for the hydrated compound in the form of $\ce{CoCl2.XH2O}$." This was a question asked in a lab report I need ...
-2
votes
0answers
31 views

Rank the following compounds from least conductive to most conductive [closed]

Rank the following compounds from least conductive to most conductive. 2 M $\ce{CaCO3}$, 2 M $\ce{AlCl3}$, 4 M $\ce{CH3COOH}$, & 4 M $\ce{C6H12O6}$
0
votes
0answers
19 views

Which of the following ions is expected to have the lowest value of molar conductance in aqueous solution? [closed]

Which of the following ion is expected to have lowest value of molar conductance in aqueous solution?? a. $\ce{Na+}$ b.$\ce{K+}$ c.$\ce{Rb+}$ d.$\ce{Cs+}$
1
vote
1answer
36 views

How does a limiting reactant relate to the concentration of ions in solution?

Given the question A sample of 1.50 g of lead(II) nitrate is mixed with 125 mL of 0.100 M sodium sulfate solution. What is the limiting reactant in the reaction? Calculate the concentrations of ...
0
votes
0answers
41 views

Plotting Angular Wave Functions of Orbitals

I'm taking an introductory Chemistry class, and we are asked to plot the angular wave functions for orbitals. What exactly does the angular wave function convey or represent? I'm very confused as to ...
0
votes
2answers
48 views

Given the mass of precipitate, how can I calculate the relative amount of the original dissolved compounds?

A simple mixture of $\ce{NaCl}$ and $\ce{NaBr}$ weighing $0.180~ \mathrm{g}$ is treated with $\ce{AgNO3}$ solution to give $0.3715~ \mathrm{g}$ of precipitate. Calculate the content of $\ce{NaCl}$ and ...
6
votes
1answer
84 views

Determine what the unknown element is

A piece of electronic equipment originally contained 1.250 g of a valuable metal. Corrosion over time has given a compound of formula $\ce{M(OH)3}$, which is isolated but not weighed. This compound is ...
-1
votes
0answers
44 views

How to calculate Kₚ from partial pressures at different temperatures? [on hold]

At $25~^\circ\mathrm{C}$ and $1~\mathrm{atm}$, the partial pressures in an equilibrium mixture of $\ce{N2O4}$ and $\ce{NO2}$ are $0.7$ and $0.3$ respectively. Calculate their partial pressures ...
1
vote
2answers
41 views

Finding initial pressure in a chemical equilibrium

Consider the equilibrium below. If $K = 4$ and initial pressures of $\ce{CO}$ and $\ce{H2O}$ are equal, giving a total pressure of $1.5~\mathrm{bar}$ at equilibrium. What was the initial pressure of ...
0
votes
1answer
28 views

Rate of Consumption [closed]

For a practice test I had to do this question: An experiment is done to determine the rate of the following reaction: $$\ce{2Al(s) + 6HCl(aq) → 3H2(g) + 2AlCl3(aq)}$$ ...
7
votes
1answer
59 views

Caclulating the Solubility of Fluorite in River Water

I am attempting to work through problems in Chapter 4 of Brunlow's 1979 Geochemistry text. The question is "Calculate the solubility of fluorite in river water with the average composition given in ...
1
vote
2answers
39 views

Titration and calculation of the number of moles after a mix

I have the following problem on an assignment that I don't understand. Given the following balanced equation for the titration of HCl with NaOH: $\ce{HCl + NaOH -> NaCl + H2O}$ The initial ...
0
votes
1answer
29 views

How much oxygen and carbon must be combined to create exactly 100.0 g of CO2 without any leftover? [closed]

I'm completely stumped on this one. Everything needed for the question is in the title. I know that 20.0 g of carbon and 32.0 g of oxygen make 44.0 g of $\mathrm{CO_2}$ with 8.0 carbon leftover.
2
votes
2answers
39 views

Find new energy level of H atom absorbing a photon

The problem I'm on says a ground state H atom absorbs a photon of 97.20nm, what energy level does it jump to. So n would start at 1. I don't have an equation specifically for a change in n though. I ...
0
votes
0answers
20 views

Finding mass equivalence of a photon

The problem has a flame emitting a wavelength of 589nm, and asks for the mass of one photon of that wavelength. I tells me that 1 J = 1 kgm^2/s^2. I converted to J using E=(hc)/wavelength. I'm not ...
1
vote
1answer
86 views

Using combined gas law to calculate the volume of dry hydrogen gas

Pv/t = pv/t is the equation of combined gas law. Say if the volume of wet hydrogen gas is 40.48ml does this equation still work if part of that volume is water vapor. Or in another word, does the ...
0
votes
0answers
15 views

How to calculate the volume of dry hydrogen in magnesium/ HCl reaction [duplicate]

Sorry if this will sound trivial, I am not too sure if the moles of $H_2$ in the equation $Mg(s) + 2HCl(aq)\rightarrow MgCl_2(aq) + H_2$ is that of dry or wet hydrogen. If the $H_2$ refers to wet ...
0
votes
1answer
27 views

Stoichiometry of Gaseous Reactions

The Question: How many liters of $H_2S$ would be required to react with excess oxygen to produce $12.0$ $L$ of $SO_2$? The reaction yield is $88.5$%. Assume constant temperature and pressure ...
0
votes
2answers
50 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 ...
2
votes
2answers
52 views

How do I figure out the relative polarity of organic compounds?

It's a question on my quiz which I guessed right and couldn't do the reasoning: Based on the intermolecular forces, predict the boiling points of the following substances and list them in the ...
0
votes
1answer
35 views

Given volume of reagents find the chemical formula of nitrogen oxide

I have difficulties solving a high school type of problem. $\ce{NH3 + O2 -> N_{x}O_{y} + H2O}$ I know that there is 1 $m^3$ of both the nitrogen oxide and the ammonia and the volume of oxygen on ...
1
vote
1answer
24 views

Are the rules proposed by slater for the calculation of Z effective right?

Today, I studied Slater's rules for calculating the effective nuclear charge. But, one particular line " The shielding power of the d and f orbital is lesser in comparison to the p and s orbitals" ...
2
votes
1answer
23 views

A metal Q forms a carbonate and a nitrate. What is the molecular formula of the nitrate of Q?

Good day. This is my first post in any chemistry site. A metal $\ce{Q}$ forms a carbonate and a nitrate. The molecular formula of the carbonate of $\ce{Q}$ is $\ce{QCO3}$. What is the molecular ...
1
vote
1answer
18 views

Is the volume of a protein substrate equal before and after an enzymatic reaction? (pepsin degrading egg white suspension)

I am trying to determine the reaction rate of pepsin at different pH values by performing an experiment. I am using egg-white suspension as the substrate and am adding differently concentrated ...
0
votes
0answers
25 views

Orbital representations [duplicate]

The usual 'orbitals' that we draw are drawn with the axes shown and everything. But orbitals are really only 1 electron wave functions of 3 dimensions... Therefore, they can't be plotted as such in ...
3
votes
0answers
44 views

Irreducible Representations to Classify Atomic Orbitals [duplicate]

I have some major confusion on Irreducible Representations. An example of a problem i have is Based on the character table for the point group of each of the follwing molecules, which irreducible ...
1
vote
2answers
37 views

Hydrolysis of Dimethyl dichlorosilane

Dimethyl dichlorosilane will undergo hydrolysis to form siloxane polymers. But why would its carbon analog Dimethyl dichlorocarbon not be able to undergo a similar hydrolysis reaction to form ...
3
votes
1answer
42 views

Electrolysis of a solution of zinc sulfate

Thr question is: Describe how zinc metal can be obtained from zinc sulfate solution by electrolysis. A labelled diagram is acceptable. Include all the products of this electrolysis. The ...
3
votes
1answer
716 views

Determining iron content in spinach from absorbency

I used a spectrometer to find the absorbency of 5 solutions with different iron concentrations. ...
2
votes
2answers
198 views

What splitting pattern is this?

I am trying to find the structure of an unknown molecule. What is the splitting pattern of these sets of lines? I think my unknown molecule is butanol and the hydrogens this splitting pattern is ...
0
votes
0answers
52 views

Finding Root-Mean-Square of Ne using kinetic energy?

I am not being able to solve the following question: -Find the root-mean-square speed of $\ce{Ne}$ atoms at the temperature at which their kinetic energy is $\mathrm{6.24\ kJ/mol}$. I tried ...
-1
votes
0answers
31 views

How do I determine the Ka using an ICE chart of an unknown acid titration using NaOH

two trials were ran using 10 mL of an unknown acid into a $\ce{NaOH}$ solution until the pH reached equivalence (pH of around or as close to 7). Using this data, I have made two graphs and I am ...
-1
votes
1answer
43 views

Use The Half Reaction Method to Balance the Following Equation in Acidic Solution [closed]

$\ce{Fe^2+ + MnO4- -> Fe^3+ + Mn^2+}$ What steps should I take?
5
votes
2answers
61 views

How to determine peroxy oxygen?

Which of the following compound doesn't contain peroxy oxygen? $\ce{CrO5}$ $\ce{Cr2O3}$ $\ce{Na2O2}$ $\ce{BaO2}$ I think peroxy oxygen peroxide(am I right?). I have read in this answer that there ...
0
votes
0answers
30 views

Assign the configurations of the stereo centres in (-)-menthol and (+)-neomenthol?

I have to assign R or S to the chiral centres in (-)-Menthol and (+)-Neomenthol. The results I got are shown below in the picture. However, when I looked on wikipedia to check my answers they ...