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 ...

learn more… | top users | synonyms

1
vote
3answers
38 views

Plotting p/T against T

This is about the ideal gas equation $$pV=nRT$$ to plot ${p}\over{T}$ against $T$, where ${nR}\over{V}$ is constant. How would this graph look like?
2
votes
2answers
89 views

Lowest CAS Registry Number on Record

I've been looking for a while and I still can't get a straight answer. I just need to know the lowest CAS Registry Number on record and the corresponding chemical.
0
votes
0answers
19 views

Wavelength of Sound Wave [on hold]

What is the wavelength of the musical note A = 440 hz when it is propagated through air in which the velocity of sound is 343 m s–1? I am taking Chemistry online and I am unsure how to solve it. Thank ...
1
vote
2answers
59 views

How do I list these elements according to their radius?

$\mathrm{Z=33,\ Z=37,\ Z=9,\ Z=31}$ Since we shouldn't look at the periodic table, I found their groups and periods, what should I do next?
1
vote
1answer
44 views

Adding water on CH₃COONa. What's the new pH?

We have $10 \,\mathrm{L}$ of solution of $\ce{CH_3COONa}$ with concentration $C=1\,\mathrm{M}$ and $\mathrm{pH}=10$. Then we ad $90\,\mathrm{L} \space \ce{H_2O}$. The question is what will be the pH ...
2
votes
1answer
54 views

How to find the mass spectrum of Cl₃⁺?

The setting of this problem is on the moon of Jupiter: Io. Given that Chlorine exists in two isotopes: $\ce{{}^{35}_{17}Cl}~(33.3\%)$ and $\ce{{}^{37}_{17}Cl}~(66.7\%)$, what is the mass spectrum ...
0
votes
0answers
15 views

How do you find emf from water concentrations? [on hold]

A concentration cell constructed from two hydrogen electrodes, both with $P(\ce{H2}) = 1.00$. One electrode is immersed in pure $\ce{H2O}$ and the other in $6.0~\mathrm{M}$ hydrochloric acid. What ...
0
votes
0answers
18 views

How to calculate the relative atomic mass of a metal via titration experiment? [closed]

$0.485~\mathrm{g}$ of a group 2 metal was dissolved in $25~\mathrm{cm^3}$ of $1~\mathrm{mol\cdot dm^{-3}}$ sulphuric acid. The solution that remained after the reaction needed $10~\mathrm{cm^3}$ of ...
0
votes
1answer
24 views

How to calculate the purity of a NaOH solution by titration? [closed]

'A solution was made by dissolving $\mathrm{7.5~ g}$ $\ce{NaOH}$, containing an inert impurity, in water and making up $\mathrm{250~ cm^3}$ of solution. If $\mathrm{20~cm^3}$ of this solution is ...
0
votes
2answers
20 views

Comparing Numbers with Different Significant Digit Precision

A while ago in chemistry class, I was asked to calculate the density of a rectangular prism, mass / (length * width * height), and then propogate the error. So I did the math and I got some value, ...
0
votes
1answer
31 views

A chemical compound with these conditions?

I am searching for a chemical compound wich meets these five conditions! slightly soluble in water layered strutcture ionic conductor thermochromism lead must be a part of it. I hope someone can ...
0
votes
0answers
21 views

Is glycerol/glycerin soluble in ethanol?

As titled, I wish to know if glycerol/glycerin is soluble in ethanol (not soluble, slightly soluble, very soluble)
0
votes
0answers
21 views

Ksp from total concentration [closed]

I am really stuck with this question, anyones help would be greatly appreciated :) The total concentration of dissolved ions in a saturated solution of calcium hydroxide, $\ce{Ca(OH)2}$, at 25 °C was ...
-1
votes
1answer
37 views

Ammonia and percent yield [closed]

$\ce{N2 (g) + 3 H2 (g) → 2NH3 (g)}$ When $\mathrm{450 g}$ of hydrogen was reacted with excess nitrogen, $\mathrm{1575 g}$ of ammonia were produced. What is the percent yield of this reaction? ...
-1
votes
1answer
47 views

Water and Silicon dioxide [closed]

$$\ce{4 HF (g) + SiO2 (s) → SiF4 (g) + 2H2O (l)}$$ What mass of water (in grams) is produced by the reaction of $\mathrm{20.0 g}$ of $\ce{SiO2}$?
-1
votes
2answers
46 views

Reaction in Chemistry [closed]

Hydrogen fluoride, $\ce{HF}$ is one of the few substances that reacts with glass (which is made of silicon dioxide, $\ce{SiO2}$) by the formula below. $$\ce{4 HF (g) + SiO2 (s) → SiF4 (g) + 2H2O ...
0
votes
2answers
53 views

Butane and Carbon dioxide [closed]

Butane, $\ce{C4H10}$, reacts with oxygen, to form water and carbon dioxide as shown in the following chemical equation: $$\ce{2 C4H10 + 13 O2 → 8 CO2 + 10 H2O}$$ Calculate the mass of butane needed ...
0
votes
0answers
53 views

Combustion of butane [closed]

2 C4H10 + 13 O2 → 8 CO2 + 10 H2O Question: Calculate the mass of water produced when 3.46 g of butane reacts with excess oxygen.
0
votes
0answers
24 views

hydrogen electrode [closed]

The hydrogen gas in the hydrogen electrode should be bubbled continuously through the electrolyte in a hydrogen electrode in order to satisfy one of the following requirement which is: A. To keep ...
0
votes
1answer
30 views

Limiting reactant and Percent Yield [closed]

When 8.8 grams of sodium chloride reacts with 4.5 grams of silver nitrate, how many grams of the precipitate silver chloride are produced? Would you end up with 21.43g AgCl and 3.77g AgCl when you ...
0
votes
0answers
29 views

Please explain the reaction mechanisms of the following synthesis [closed]

Tried to find out the reaction mechanisms but could not, please help.
2
votes
1answer
51 views

Finding pH of a buffer solution

A $\ce{pH}$ 4.88 buffer was prepared by dissolving 0.10 mol of benzoic acid (Ka = 6.3 . 10-5) and 0.50 mol of sodium benzoate in sufficient pure water to form 1.00 L solution. To a 70.0ml aliquot of ...
0
votes
1answer
36 views

How to calculate the temperature from heat of neutralisation?

The heat of neutralization of $\ce{HCl~ (aq)}$ by $\ce{NaOH}$ is $\mathrm{-55.9~kJ/mol}$ $\ce{H2O}$ produced. If $\mathrm{50~ml}$ of $\mathrm{1.6~M}$ $\ce{NaOH}$ at 25.15 celsius is added to ...
0
votes
0answers
19 views

Iodine and persulfate kinetics: What can be deduced from graph?

From a graph of iodine concentration vs time of the reaction of iodide with persulfate, what can be deduced? Is it possible to find the order with respect to iodide and with respect to persulfate?
0
votes
2answers
75 views

deduce the structural formulae of isomers of X [closed]

100cm3 of alkane X with the general formula CxHy requires 650cm3 of oxygen for complete combustion. Deduce the structural formulae for the isomers of X
4
votes
1answer
33 views

How do I calculate the concentration of H₂SO₄ by a titration experiment with NaOH?

In my latest chem lab the objective was to create a primary standard of $\ce{NaOH}$ and use it to determine the concentration of sulfuric acid. The first part of the lab was determine the molarity of ...
4
votes
2answers
62 views

Finding rate constant at different temperature

For the reaction $$ \ce{2N2O5(g) -> 4NO2 + O2(g)} $$ the rate law is: $$ \frac{\mathrm{d}[\ce{O2}]}{\mathrm{d}t} = k[\ce{N2O5}] $$ At 300 K, the half-life is 2.50·104 seconds and the activation ...
0
votes
0answers
53 views

Histidine-Phosphate in Succinyl CoA synthetase and phosphoglycerate mutase enzyme

I would need to know the type of bond of histidine-phosphate in succinyl CoA synthetase enzyme. Can anyone help with this? Is it a Carboxy phosphate anhydride ? Is it the same type of bond of ...
3
votes
1answer
37 views

Transfer of energy

After completing a lab for my chemistry class I am finding it difficult to find the initial temperature of an iron nail after being heated. Procedure of the lab went as follows: heat an iron nail, ...
2
votes
2answers
74 views

Can Ketones next to a Nitrogen hetero atom tautomerise?

I worry that the electronegative N will stabilise keto form so much that equilibrium will be so far towards keto it would be unreasonable to call the enolisiation process a factor
3
votes
2answers
61 views

Experimental chemistry (Planning an experiment)

The benzyloxycarbonyl group (CBZ) is widely used to protect amines, especially in amino acid chemistry.A procedure to synthesise the CBZ derivative of glycine from glycine and benzyl chloroformate is ...
0
votes
0answers
35 views

Calculating mass and volume of two different substances required for one solution

I want to produce a solution, which contains $0.02~\mathrm{mol~L}^{-1}~\mathrm{Cu}^{2+}$ and $~0.2~\mathrm{mol~L}^{-1}~\mathrm{NH}_3$. The following substances are given: copper(II) sulfate ...
1
vote
1answer
67 views

Redox Question: Concentration of Pb2+ is unknown

What is the concentration of $\ce{Pb^{2+}}$ in a lake that has a pH of 6.0 and is in equilibrium with $\ce{PbO2(s)}$ and atmospheric oxygen? $\ce{PbO2(s) +4H+ +2e- -> Pb2+ +2H2O}$ log K = 49.2 ...
1
vote
3answers
59 views

Filling a buret tip before an experiment

I have a question that asks if the buret tip is not filled before the experiment what would happen (effect on molarity for acid/base titration). The way I'm thinking about it, it's not like you're ...
0
votes
1answer
43 views

How can I balance the redox reaction of sulfur dioxide with oxygen?

How do I balance this reaction using half-redox equations? $$\ce{2SO2 + O2->2SO3}$$ My work is: Oxidation: $\ce{SO2 + H2O -> SO3 + 2e- + 2H+}$ Reduction: $\ce{H2O + 2e- + O2 -> SO3 + ...
0
votes
2answers
43 views

contact process<application of Sulphuric acid in industry>

Choose the two correct options from A-F, why it is not commercially suitable to dissolve $\ce{SO3}$ directly in water to give concentrated sulphuric acid instead of contact process? The major reaction ...
1
vote
1answer
61 views

Calculate the degree of dissociation of AlCl3

I'm having trouble figuring out where to go with this question. Calculate the degree of dissociation of $\ce{AlCl3}$ if molar conductivity of the solution is $31.3\ \mathrm{mS\ m^2\ mol^{-1}}$ and ...
0
votes
2answers
24 views

Chemical Equation & standard enthalpy change [closed]

Can a chemical equation be product --> reactants. For example in the equation, 2NCl --> N2 + Cl2, which is the product and which is the reactant? Also, how would you set up a standard enthalpy ...
1
vote
1answer
27 views

Denaturing of Proteins and Nucleic Acids - Effect of Temperature (Heating VS Cooling)

Heating a protein/nucleic acid will disrupt inter-molecular and intra-molecular forces in the tertiary structure. It will also interfere with the shape of the active site if the protein. Does this ...
2
votes
2answers
83 views

Why is an excited helium dimer created in this collision experiment?

Why does a collision between an excited helium molecule (He*) and a ground-state helium atom create He2*? Is it something to do with the lower-energy orbitals? I'm not really sure at all.
1
vote
1answer
80 views

Why is there an exponent 4 after the brackets in sp3?

My professor wrote an electron configuration for carbon as: 1s2 (sp3)4 I thought it was just 1s2 sp3 where did the 4 come from?
2
votes
0answers
27 views

Why would ethanol or water give poor yields in a peptide deprotection hydrogenolysis?

A homework question asks: The following reaction was carried out using ethanol or water as solvents, but gave poor yields in both cases. Suggest why this might be the case and how these problems ...
0
votes
1answer
44 views

How much sulfuric acid is necessary to completely react with lithium hydroxide? How do I find the concentration when a volume is given? [closed]

What is the molarity of sulfuric acid if 15.4 mL are required to react with 50.0mL of 0.353M lithium hydroxide? $$\ce{H2SO4 (aq) + 2LiOH (aq) -> Li2SO4(aq) + 2H2O(l)}$$
0
votes
0answers
3 views

required DM water quantity to dilute Acetic acid

I have acetic acid (glacial) 100% with a pH of 2.4. and i want to know how much DM water required to dilute acetic acid and obtain a pH of 4.3. as per observation 0.0001M is equal to 4.3 pH. so how ...
0
votes
3answers
55 views

Empirical Formula Worded Problem

5.00 g of nitrogen is completely converted into an oxide of nitrogen. The mass of the oxide formed is 19.3 g. The empirical formula of the oxide would be My working: $\ce{N2 + O_2 -> ...
0
votes
1answer
34 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 ...
0
votes
1answer
24 views

How do I calculate equilibrium partial pressures of $\ce{H2}$, $\ce{N2}$, and $\ce{H2O}$ and $K_{eq}$ for this problem?

This is the complete problem: A mixture of $0.10$ mol of $\ce{NO}$, $0.050$ mol of $\ce{H2}$, and $0.10$ mol of $\ce{H2O}$ is placed in a $1.0$ L vessel at $300$ K. The following equilibrium is ...
2
votes
0answers
26 views

How to predict the type of intrinsic defect?

How do we predict the type of intrinsic defects in materials. For example what are the intrinsic defects in $\ce{HgSe}$ and $\ce{Ba3N2}$ ?
2
votes
1answer
19 views

Factors to consider to predict EPR

What are the factors to consider when predicting the EPR spectrum of $\ce{Cu(Ox)P(CH3)3}$ where $\ce{OX}$ is the oxalate ion? I understand that there are several factors to consider for EPR (Electron ...
1
vote
1answer
18 views

Gas laws question, condensed partial pressure?

So I'm relatively new to gas laws as I just started learning it at school. I've been doing fine so far until I got stuck on this question, any ideas? A mixture of three gases N2, CO2 and O2 has a ...