Questions tagged [concentration]
The concentration characterizes the composition of a mixture with respect to the volume of the mixture. There are mass, amount, number and volume concentrations. Related and within the scope of this tag are normality, molality, mole fraction/ratio, mass fraction/ratio.
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Calculate concentration of product after time passed
If I have two parallel reactions:
A --> P$1$ (k$_1$ = $0.00010$ s$^{-1}$)
A --> P$2$ (k$_2$ = $0.00050$ s$^{-1}$)
and know that the initial concentration of A is $0.0417$ M. How can I ...
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Determining reaction order from absorbance
A reaction is initiated in a solution which contained a dissolved component. The transmittance was measured at $\pu{240 nm}$ in a $\pu{2.54 cm}$ long cell. At $t = 0$ the transmittance was $1$. $\...
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Could Nernst Equation fail at high Ion concentration diffrence
When I was learning about neuroscience, I came across the Nernst equation and found out that it is only dependent on the quotient of the ion concentration outside compared to the inside. So, now I ...
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Why we are dividing rate of reaction with respect to a species by its stoichiometry coefficient to find rate of that particular reaction
If there is a reaction like this
$$\ce{ H2 + Cl2 -> 2HCl}$$
I can understand that each individual species (reactant or product) can have different rates and we can compare them like this,
$$-\frac{...
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How much solvent do you add for a 1:20 dilution, and why is it called 1 to 20? [closed]
A 1:20 dilution implies that you take 1 part of stock solution and add 19 parts of water to get a total volume of diluted solution equal to 20 times that of the stock solution
So is ...
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Plotting second order reaction with different reactants
In a laser flash photolysis experiment, $\ce{C6H5NH2}$ $(C_0 = \pu{60 \mu M})$ is oxidize to its corresponding radical cations. There are three possible reaction pathways for the formation of the ...
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Is this true for conductivity of mixture of two solutions equal to the sum of conductivities of each solution?
Suppose $\ce{Na2SO4}$ has a conductivity $\pu{2.6 \times 10^{-4} S cm-1}$ and on mixing $\ce{CaSO4}$ to saturation, the conductivity becomes $\pu{7.0 \times 10^{-4} S cm-1}$.
So, Is the conductivity ...
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Quantifying soapiness; there's pH, pKa and pO2, is there a p_soap or p_surfactance?
Yes, $\mathrm{pH}$ is a concentration, $\mathrm{p}K_\mathrm{a}$ is a dissociation constant, and $\mathrm{pO_2}$ is a partial pressure. These are (roughly speaking) ways to indicate how much of a key ...
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Calculating the weight of a chemical within a liquid mixture
I want to know the weight of ethylene glycol in a mixture of Shellzone 50/50 Antifreeze. I have taken the mid-range of 40-60% from the safety data sheet(SDS) for the amount of ethylene glycol in the ...
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Translating from milligrams in the pill to Ki at the receptor
Many places (e.g. Wikipedia) report the action of a drug on the various receptors, transporters, ion channels, and the like in terms of the Ki(nM). (This is for drugs that act primarily through such ...
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Why is the concentration of gases denoted in form of partial pressure? [duplicate]
In most of the chemical laws of chemistry involving concentration of products or reactants like equilibrium constant, reaction quotient, Henry's law, Nernst equation etc, I often see a similar note ...
user112102
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Hydrogen concentration measurement without gas chromatography
Please suggest ways to measure $\ce{H2}$ concentration in a sample of gas containing $\ce{HCl},$ $\ce{CH4},$ $\ce{N2},$ $\ce{CO2}$ and trace amounts of chlorosilanes without GC.
The problem is that I ...
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Calculating molarity of iodine solution after reaction
I made an iodine solution referring to the methodology provided in this link:
https://www.thoughtco.com/vitamin-c-determination-by-iodine-titration-606322
$$\ce{KIO3 + 5KI + 3H2SO4->3I2 + 3H2O + ...
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A physical meaning of the Danckwerts boundary condition in terms of concentration profile (adsorption)
Can someone please explain to me in a simplified way, what exactly does a well-recognized Danckwerts boundary condition do to the concentration profile of adsorption phenomena? I just cannot find a ...
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The effect of increasing concentration of a cathode solution on the voltage in a galvanic cell
I am having trouble understanding a concept. In a galvanic cell, where electrolyte A is zinc (in a solution of zinc nitrate) and electrolyte B is copper (in a solution of copper (II) nitrate), why ...
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Effect of addition of inert gas on concentration in an equilibrium [duplicate]
We have the following equilibrium established in a container with movable piston at atmospheric pressure.
$$\ce{N_2 (g) + 3 H2 (g) ⇌ 2NH_3 (g)}$$
Now how does the concentration of the reacting species ...
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Rate of a reaction when volume of the system varies with time
Background
I was solving this question from this book and I was not able to get any of the options.
The gaseous reaction $\ce{n_1 A_{(g)} -> n_2 B_{(g)}}$ is first order with respect to ‘A’. The ...
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Relationship between molar mass and density in solids
In ideal gases, it's pretty clear that 1 mole of gas occupies 22.4 L at STP. By knowing this, it's easy to calculate density given molar mass. However, this isn't true for solids. If I know molar mass ...
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Calculating the ionic strength for an aqueous solution containing potassium ferricyanide and sodium sulfate
I have the $100$ microM of K$_3$Fe(CN)$_6$ is dissolved in water and the following data:
$$\begin{array}{c|c}
\text{Experiment} & \ce{[Na_2SO_4]}/\pu{M} \\ \hline
\mathrm{A} & 0 \\
\mathrm{B} ...
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will splitting a solution will keep the concentration values (and moles) the same? [closed]
I have this exercise from my H.W:
and I am asked: if we split the solution into 3 different containers equally -
how many moles will the solution have in each container?
will the Cl- concentration ...
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Discrepancy when calulating mol weights with ChemSketch and Python RDKit
I am an IT guy with little knowledge of Chemistry, so please bear with me...
For context: I am working with a system that has a lot of structures, their .mol files ...
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Finding mass percent through molality of potassium nitrate solution
Question
An aqueous $\ce{KNO3}$ solution has a molality of $\pu{4.16 m}$ and a density of $\pu{1.08 g/mL}$. Calculate the percentage by mass $\ce{KNO3}$ of the solution.
My Approach
I know that ...
user109283
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The effect of dilution on the rate of a system in equilibrium
I'm attempting to answer a question from my textbook, however the answer that the textbook provides doesn't make sense to me.
The question:
Laura, a VCE chemistry student, loves graphs and wanted to ...
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Is the rate of a zero order reaction always independent of the concentration of its reactants?
Consider the following reaction :
$\ce{A + B}$ $\rightarrow$ $\ce{Products}$
where order of the reaction w.r.t. $\ce{A}$ is $-1$ and order of the reaction w.r.t. $\ce{B}$ is $+1$. So, overall order of ...
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Total concentration conversion
when dealing with waste water and the total values of P, N, C are given in ppm units, what molecular weight is used for converting from ppm to molar?
for Example- what will be 12 ppm of P(T) in Molar ...
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More ions form pairs when concentration of acid increases, does that decrease the speed of reaction?
Electrical conductivity decreases as an acid becomes more concentrated because more ions form pairs. However, does that affect the speed of reaction of the acid as there is a smaller concentration of ...
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Finding the concentration from a dilution
This must be a very basic question but I have gotten confused over it.
How would I find the concentration of each component of the reaction for each experiment from this data? I am guessing it can’t ...
user85551
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Physical Chemistry: Specifically the Dissolution of Carbonates
Please note this question is different to the other that keeps being mentioned. That one is about the concentration of just $\ce{HCO3-}$ when no $\ce {pH}$ was given.
Whereas, in this one I am trying ...
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Do you need concentrated sulfuric acid to make Dische diphenylamine reagent and test for DNA?
I'd like to do a DNA quantification experiment for a college project. I don't want to use 16 M sulfuric acid. Is it possible to use more dilute acid and get a reasonably good result?
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Finding reaction rate constant for second order equation in Wolfram Mathematica [closed]
I’m working in Mathematica for my master’s project and I can’t work out how to find $k$ in the second order rate equations where I have a concentration vs time graph for $\ce{AHA}:$
$$\mathrm{rate} = ...
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Adding aluminum sulfate to neutralize an aqueous solution of sodium silicate with pH of 12.6
How much aluminum sulfate do I need to add to an aqueous solution of sodium silicate to neutralize the solution (pH from 12.6 to 7)?
For a water treatment school project, we remove sodium silicate ...
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Enthalpy of dissolution of NaOH in small amount of water
is there a way to calculate enthalpy of dissolution of NaOH in small amount of water?
I know that enthalpy of dissolution of sodium hydroxide in water is –44,5 kJ/mol. However it assumes the orders of ...
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How to calculate molar concentration from equilibrium equations with no initial concentration given?
I have the equations:
\begin{align}
\ce{CO2(g) + H2O(l) &<=> H2CO3(aq)} &\quad K_1 &= 10^{-1.47} \tag{1}\\
\ce{H2CO3(aq) &<=> H+(aq) + HCO3-(aq)} &\quad K_2 &= 10^{-...
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How to identify the concentration of nitric acid?
I have quite a small quantity of concentrated nitric acid I had acquired about two years ago. This was given to me by a friend in a couple of Pyrex volumetric flasks with stopper and some in a ...
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Why would sodium ions want to go down just because of one side is more positive than the other? [closed]
From Khan Academy starting from 1:25, the narrator, while talking about the Electrochemical gradients, said that sodium ions would naturally want to diffuse
down when having a high concentration up ...
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Does increasing one of the electrolytes in a galvanic cell increase the voltage?
I would like to know how you could increase the voltage in zinc and copper galvanic cell:
$$\ce{Zn(s) + Cu^2+ → Zn^2+ + Cu(s)}$$
I know that temperature and surface area is a factor that affects the ...
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Calculate the percentage in a solution
The aim of this exercise is to determine the percentage (degree) of acetic acid in vinegar.
For this purpose 10 mL of vinegar requires 8mL of sodium hydroxide of molar concentration
0.1mol/L to react ...
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Why is the concentration of hydrogen peroxide given as a percentage? For example, 3%, 6% [closed]
Conventionally, the concentration of solutions is given in moldm⁻³ or M, however, I am curious why the concentration of hydrogen peroxide isn't written in the same way.
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Calculation of concentration at equilibrium for extraction
The equation for equilibrium of solvent-solvent extraction is:
$$\ce{PhOH(toluene) <=> PhOH (aq)}$$
An aqueous solution contain $\pu{1.5 \times 10^{-2} M}$ phenol and is shaken with the same ...
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Aluminum electrodes for NaCl [duplicate]
Upon using aluminium Electrodes for a concentrated solution of NaCl, i conducted electrolysis on the solution for nearly 4-5 hours. There was definitely a gas possibly hydrogen being evolved at the ...
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How do I prepare citric acid solution (from anhydrous powder) of accurate concentration, given that the solution volume expands when water is added?
I attempted to prepare saturated citric acid solution from anhydrous powder. According to online data, the solubility limit was 59.2 w/w at 20 °C, i.e. 59.2 g citric acid in 100 mL water. To ensure ...
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Is it valid to calculate concentrations given equilibrium constant and initial concentration?
Suppose we have the following reaction:
$$\ce{2A <=> B + C}\tag{1}$$
which can be thought the sum of the following reactions:
$$\ce{A <=> B}\tag{2}$$
$$\ce{A <=> C}\tag{3}$$
with ...
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Reversible equation in Chemical Kinetics — Should I use definite integral when solving the differential equation?
I found this problem:
We have the following reversible reaction: $A \ce{<=>[\ce{k_1}][\ce{k_2}]} B $, described by the kinetics equation:
$$\frac{d[X]}{dt} = k_1([A]_0-[X])-k_2([B]_0+[X])$$
...
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Combining solutions with multiple concentrations - Mixing NPK fertilizer ratios
I'm trying to mix my own fertilizer to grow some peppers.
Fertilizers are labeled with NPK ratios, so mixing two volumes and finding the result is easy: Just multiply the concentration of each ...
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Chromatography- why tM is separated from other peaks? [closed]
tM in Chromatography is the time of exist mobile phase. But, the mobile phase exist together with all the compunds that tasted in the process. So, why in the graph of signal to time we can see a peak ...
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Why are these two methods of converting from ppm to g/m3 equivalent?
I've found two methods to convert from $ppm$ to $g/m^3$. They both appear to give equivalent results, but I don't understand why. Can anyone join the dots for me and explain why they are equivalent ...
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Find minimum solubilty of AgCN [closed]
i know it has to be solved by writing an equation between CN- conc and solubilty but i am unable to write a non-linear equation,any help is appreciated
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Is Molarity constant? [closed]
My friend and I were debating about if Molarity is constant in a disolution if this one changes volume due to evaporation.
There was this problem that stated that 125 [mL] of sodyum chloride 0.122 [M] ...
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How does strong acids conduct electricity in water?
How do strong acids conduct electricity in water?
I have just studied ionization of water and I'm confused about some points.
First: I know that water ionizes in a very small amount ($10^{-14}$) so ...
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Is 1% m/m the same as 1% w/w?
Hydrocortisone cream seems to be sold as 1% w/w, but my cream is 1% m/m, which is confusing. Are they the same units or the same concentrations?
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