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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How can I make AgNO3 more basic?

Is there anything that I can add to the AgNO3 solution that will make it more basic without forming a precipitate such as reacting with OH or HCl? Please be more specific and give an example.
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Protons and osmotic potential

In a hypothetical enclosed membrane only permeable to water (including hydronium), where inside the pH is lower than the outside, would water move inside?
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Chem 20 – Combined Law/Molar Volume/Ideal Gas Law [closed]

In an engine, a fuel-air mixture at atmospheric pressure is compressed rapidly from 500 mL to 60 mL, while the temperature increases from 100 °C to 1000 °C. (a) What is the new pressure of the mixture ...
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Creating 1L of 1000 ppb stock solution of Pb2+

I’m testing on samples that require a concentration of 1000 ppb (or 1 mg/L) of Pb 2+. My first thought was to simply dissolve 1 mg of Lead nitrate in 1 L of deionized distilled water to create 1 L of ...
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At 100 degrees C, the reaction: N2(g) + O2(g) ⇄ 2NO(g) has Keq = 0.0010 7.5 mol of NO is added to a 250 mL flask [closed]

]1) I need assistance on how I can find an answer to this question please and thank you.
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Concentrating Ethanol from 70% to 100% [closed]

I want to dry 70% alcohol (ethanol) to get 100% concentration, without using molecular sieves. What would be the easiest and most inexpensive method to do that?
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Protein concentration in the cell from concentration in nucleus and cytoplasm

I have two quantities obtained by simulation. One represents a protein concentration in the nucleus, say $X_N$ and the other the same protein concentration in the cytoplasm , say $X_C$. I have real ...
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How many g of Al(NO3)3 would be in 0.089 L of a 0.63 M solution of Al(NO3)3? [closed]

I'm stuck on this question. How many g of Al(NO3)3 would be in 0.089 L of a 0.63 M solution of Al(NO3)3?
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Chemical equilibrum [closed]

An equimolecular mixture of NH3 and O2 is contained in a container. After the oxidation reaction took place to obtain NO, the equilibrium is established: 4NH3 + 5O2 ⇌ 4NO + 6H2O + Q It is found that ...
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Discrepancy between the apparent volume of the solution and the volume of the solute arising from the definition of solubility

I have solubility $s$ given in $\pu{g/mL}.$ I understand this as mass of solute $m$ divided by volume of solvent $V.$ But how about the volume of the resulting solution? I read online I should pour ...
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Active masses of solids and liquids [duplicate]

In the calculation for equilibrium constant, we take the active mass of solids and liquids as unity. Intuition tells that more amount of a solid reactant should result in more product being formed, ...
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Topical hand sanitizer production question from tutor; Concentration and dilution of chemicals of known concentrations [closed]

The question is as follows: You are in charge of making hand sanitiser based on the WHO Guide to handrub formulations, FORMULATION 1 Final concentrations: • Ethanol 80% (v/v), • Glycerol 1.45% (v/v)...
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Concentration when done wrt mass or volume [closed]

I have a question asked in jee main 2020. 10.30 mg of o2 is dissolved into a litre of sea water of density 1.03 g/ml. The concentration of o2 in ppm is? Well I know that ppm is generally possibly ...
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Too much leftover in zinc sulfate reaction?

I'm doing a reaction of zinc metal and sulfuric acid to get zinc sulfate. I've been trying to learn the chemistry lately so I tried to measure out correct molar amounts. My understanding from the ...
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How to recalibrate qpCR reading when incorrect qty of solution is added during DNA elution step?

I have 20 viral DNA samples collected for 6 time points. The DNA content varies over time My DNA extraction protocol step suggests that in the last step of the protocol during elution I had 100uL of ...
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Why is measurement in molarity preferred over molality?

NCERT Chemistry Part 1 states that: "The osmotic pressure method has the advantage over other methods as pressure measurement is around the room temperature and the molarity of the solution is used ...
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Concentrating Isopropyl alchohol using non-iodized salt

I am using 99% isopropyl alchohol to clean soldering flux residues for my electronics projects. Due to a certain viruse running amok in the world today, I am not able to get from my usual supplier. I ...
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What effect is on the rate and rate constant when concentration or temperature increases/decreases?

I have a few questions regarding rate and rate constant. I am wondering what effect certain concentrations, temperature, etc., has on rate and rate constant. Would be of great help if you can clarify ...
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Hydrochloric acid substitute in an Iron-gall ink solution

Recently I started experimenting with making my own ink to be used in fountain pens. I was wondering if hydrochloric acid in an iron-gall ink is used to prevent sediment ONLY by lowering the pH of ...
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Why is the equilibrium constant for a Daniell cell not equal 1?

Using the equation $$RT\ln K = nFE,$$ the equilibrium constant $K$ for a Daniell cell at standard conditions can be found as $$K = \exp\left(\frac{2 × 96500 × 1.1}{8.3145 × 298.15}\right) = \pu{1....
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Can the direction of electron flow in a voltaic cell be reversed? [closed]

I am wondering if the direction of electron flow in a voltaic cell be reversed such that the cathode becomes the anode and vice versa. I understand this is not possible for two standard half-cells, ...
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Nernst Equation for Lithium ion battery

For electrochemical cells we know $$ \Delta G = \Delta G^{\ominus} + RT\ln Q=- RT\ln Keq + RT\ln Q=-nFE $$ So for lithium ion batteries the reactions are Cathode $$ \ce{CoO2 + Li+ + e- <=> ...
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Can I determine the rate law order from stoichiometric coefficients?

I've read in two books, and seen in three separate videos courses, that you cannot determine the rate law order from stoichiometric coefficients. Then, I have seen homework and "practice" problems ...
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I was wondering if anyone could provide me with a method to solving as I do not know what I am doing wrong after multiple attempts?

A portland cement sample contained 20% SiO2 by weight derived from two silicate compounds, SiO2.2CaO and SiO2.3CaO that are present in the cement in the mole ratio 3 : 4. Determine the percent by ...
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If I dissolve 0.1M of CaCl2.2H2O in water, do I get a 0.1M CaCl2 solution? [closed]

If I dissolve $\pu{0.1 M}$ of $\ce{CaCl2.2H2O}$ in water, do I get a $\pu{0.1 M}$ $\ce{CaCl2}$ solution?
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Liquid fertilizer nutrient values - % weight by weight or % weight by volume?

I was convinced that liquid fertilizer labeling use the % weight by volume convention. However now I bought a magnesium-sulfur based additive. The label clearly uses % weight by weight. Weight by ...
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Molarity of two solutions

Question: Two solutions of ethanol marked as X and Y are labeled as 25% ethanol by mass and 25% ethanol by volume respectively. If the density of solution Y is 0.789 g/mL and that of solution X is 0....
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Setup for Sensing change in concentration of NaCl

I am making a sensor to sense the change in concentration of NaCl. My background is in electronics and chemistry is not my strong area. I got some screen printed electrodes, with Silver (Working ...
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Is the active mass of every solid and liquid taken to be unity?

I learnt from my textbook and the question/answer - Why is active mass of a pure solid or liquid always taken as unity? that active mass of a solid or liquid is taken to be unity as: $$[A]=\frac n V=\...
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How much of Sodium dichloro-s-triazinetrione dihydrate should I use to replace bleach? [closed]

I am trying to determine how much sodium dichloro-s-triazinetrione dihydrate powder I should add to water to create a dilution that can be injected into my water supply to react with the Hydrogen ...
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What exactly is the requirement (in terms of saturation) for a reaction to be at equilibrium? [closed]

A saturated solution is a solution that contains the max amount of solute able to be dissolved. However, can't a solution still be at equilibrium if you add more solute to a saturated solution as long ...
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Estimation of Sodium Hydroxide

Why is estimation of sodium hydroxide more accurate with oxalic acid rather than with sulfuric acid or any other strong acid?
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How and why do concentrated solutions react faster? [closed]

It seems intuitive that concentrated solutions would react faster, but, when I stopped and thought about it, I got confused. Wouldn't concentrated acids and bases be in contact with less water than ...
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How do we weigh one C atom? [closed]

As far as I get it, we did weigh one carbon (12,6-isotope) atom. Then we said that electrons have nearly zero weight and protons weight nearly the same as neutrons. Hence we took the weight of that ...
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Up to which dilution can one assume that 1 mg/l = 1 ppm?

For aqueous solutions it is often assumed that 1 milligram per liter equals 1 ppm. Are there any guidelines up to which concentration this shortcut is admissible? Are there any formulas which ...
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Why does the electrical conductivity increase as the temperature decreases?

I am measuring the dependence of electrical conductivity of ( NaCl and $\ce{CH3COONa}$ solutions with concentration 9g/L) with temperature using conductivity meter. Theoretically the conductivity ...
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Can I express the rate of a reaction as percent per second (%/s)?

Rate is calculated as change in concentration over change in time, so usually $\pu{M/s}$ $(\pu{mol L-1 s-1}).$ Say, I'm calculating it for $20\%$ solution of ammonium hydroxide, so my final rate is ...
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Calculating concentration of a powder in a liquid

I'm trying to determine how to calculate proper measurements for a 5% concentration of a vitamin C ester powder (ascorbyl palmitate) mixed in a 50/50 carrier oil mixture (jojoba oil/squalane oil) with ...
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How to calculate the amount of sodium sulfate needed to lower the silver ion concentration of a saturated silver sulfate solution?

How many moles of $\ce{Na2SO4}$ we have to add into a saturated $\pu{0.5 L}$ solution of $\ce{Ag2SO4}$ so that the concentration of $\ce{Ag}$ is $\pu{4.0 \times 10^-3 M}$? ($K_\mathrm{sp} = 1.4 \times ...
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I have a solution of citric acid, tartaric acid, water and glucose. How do I find the concentration of the citric acid present in the solution?

If I try to find the concentration of citric acid through back titration or reverse titration, the base I would use, like NaOH, would react with both acids to form sodium citrate and sodium tartrate, ...
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What formula allows adjusting balance of (Ethyl Alcohol / Water / Caffeine powder) to know concentration for the Caffeine solution?

I am experimenting with different levels of concentrated caffeine solution. The solution has a small percentage of ethyl alcohol, in the $\ce{H2O}$. Problems encountered too much ethyl alcohol ...
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510 views

Electrochemistry conditions for voltage to increase in a galvanic cell

I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always? Consider a standard cell of ...
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An exception to the IUPAC convention for italicisation (typography)

According to IUPAC, only physical quantities and variables must be italicised. Section 8 Use of Italic and Roman Fonts for Symbols in Scientific Text of ICTNS Guidelines for Drafting IUPAC Technical ...
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What is the difference between chemical equilibrium and dynamic equilibrium?

Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant. Dynamic equilibrium from ...
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Does the volume change when the reactions occur? [closed]

I have this reaction (all substances are gaseous): $$ \begin{align} \ce{A + 4.5 B &→ C + 2 D + 2 E}\tag{R1}\\ \ce{C + 7.5 B &→ 8 D + 2 E}\tag{R2} \end{align} $$ Does the volume change when ...
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How to dispose of NaOH solution? [closed]

I have a range of sodium hydroxide solutions with different concentrations. (from 1.0 mol dm^-3 to 0.5 mol dm^-3). The max volume of each is 100ml. How can you easily dispose of these? Can I pour them ...
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How to calculate the number of protons in a sphere given the volume and the pH?

The spherical radius of a nano-droplet of a solution ($\mathrm{pH}$ of which is $6$) is given as $\pu{20nm}$. I can find the molar concentration of $\ce{H+}$ and subsequently the number of $\ce{H+}$ ...
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Calculating the Ionic strength of sodium acetylsalicylate

With the addition of aqueous NaOH to an aspirin solutions in water the reaction will yield products of sodium acetylsalicylate and water. I would like to measure the amount of sodium apsirin formed ...
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Meaning of mass concentration “units” % m/v [closed]

In a saline solution that is 5.750% (m/v) potassium iodide $(\ce{KI}),$ there are: a) 5.750 mL $\ce{KI}$ per 100.0 mL $\ce{H2O}$ b) 575.0 mg $\ce{KI}$ per 10.00 mL of $\ce{KI}$ solution c) 5....
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Angels Share seems bogus

What is the explanation of barreled spirits (at 62.5% ethanol) that undergo changes in concentration of ethanol. Whereas the volume after aging is typically reduced, the proof varies between low 100 ...

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