# Questions tagged [stoichiometry]

Stoichiometry refers to the relationship between the amounts of substances of the reactants and the amount of substances of the formed products. This tag should be used for specific questions about chemical reaction equations.

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### Fuel Rich combustion

Question A fuel rich mixture of certain Hydro-Carbon fuel C12H24 and oxygen (O2) at standard condition, is burnt at a mixture ratio 2.5. Assuming initially all the H is oxidized to H2O and thereafter ...
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### Why should the pH change when I add sodium hydroxide to water? [closed]

I am a student and I am trying to understand the concept of pH. If I add pure $\ce{NaOH}$ in water, it leads to the formation of $\ce{OH-}$ ions in the water. But this shouldn't lead to any change in ...
195 views

### Net concentration of sodium hydroxide after addition of phenol red indicator

I am planning to use an acid-base reaction with an indicator for some flow studies. I will be using aqueous solutions of sodium hydroxide (NaOH) and hydrochloric acid (HCl) with phenol red as the ...
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### How do these two definitions apply to the same term?

Tushar's answer to this question (What is an equivalent?) gives two definitions for an "equivalent" An equivalent (symbol: officially equiv; unofficially but often Eq) is the amount of a ...
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### Percentage Yield

For the above MCQ question, I took the equation to be $$\ce{CaC2 + 2H2O -> C2H2 + Ca(OH)2}$$ I then calculated the moles of $\ce{CaC2}$ as 0.7273 moles, which has a 1:1 molar ratio to $\ce{C2H2}$, ...
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### Removing glass fiber from samples before mass spect run?

I would like some unbiased opinions and knowledge from you all if you have time. I am measuring Phosphorus content of snail and embryo samples. I am only interested in Phosphorous content. I ...
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1 vote
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### Use of Equivalent in organic chemistry

The question is taken from an engineering entrance exam in India(JEE 2024) If 3 mole of aniline is reacted with one equivalent of benzene diazonium chloride the maximum amount of aniline yellow formed ...
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### Different method of solving a question giving different answer [closed]

Calculate the concentration of nitric acid in moles per litre in a sample which has a density, $\pu{1.41 gmL^–1}$ and the mass per cent of nitric acid in it being $69 %$. I attempted to consider a 1L ...
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### Law of multiple proportion fitting in the notion of an atom

I have been reading about atoms. Currently, I am referring to the book "Atom : Journey across the subatomic cosmos" by Issac Asmov. I believed that if we start dividing something so we can ...
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### Model EC50/Kd values using ordinary differential equations

It is my first attempt at using ordinary differential equations to model Kd for antibody binding and help will be much appreciated. To provide some context, I possess binding curve data for the EC50 ...
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### Is it not possible to balance the equation $\ce{I2 +O3 -> I4O9 +O2}$ in many ways? [closed]

The above reaction can be balanced in many ways. For example, the coefficient of $\ce{I2}$ is two when coefficient of $\ce{I4O9}$ is one. But the coefficient of $\ce{O3}$ and $\ce{O2}$ can be 5 and 3 ...
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### How do I calculate the fuel consumption inside a cylinder-piston stoichiometrically?

Consider I have car 4-cylinders with total cylinder capacity is 1,496cc. Per piston, the cylinder is 374cc. The piston diameter is 72.5mm, height=90.6mm, and compression ratio is 11.5:1. Hence we may ...
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### Does a chemical reaction depends on the amount of reactants?

A chemical reaction depends on many things like the temperature, pressure etc. i wanted to ask if It also depends on the amount of reactants for example; If A + B gives C and assuming this equation is ...
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### Can I reuse LDPE bottles after trace element analysis?

I run some algae samples through mass spec a few times over the month to test the P content of algal samples. My (simplified) procedure was as follows: Put a small portion of algae in a teflon vessel ...
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### How to find the formula of a binary compound if we know the mass of solid product and the volume of escaped gas?

During the decomposition of a binary compound two simple substances were formed: 44.8 grams of metal and 47.04 liters of a non-flammable gas (conditions are normal). Find chemical formula of the ...
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### Parentheses use in non stoichiometric compounds

When should one use (or not) parentheses in writing the formula for non stoichiometric compounds. I mean, the mineral sphalerite is often represented by the formula $\ce{(Zn,Fe)S}$ and, all though I ...
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### Calculation of the retained mass after hydrolysis of an oligopeptide

I would like to ask about a problem that I am stuck on: An oligopeptide is made up of glycine, alanine, and valine. Hydrolysis of X in $\pu{500 mL}$ of $\pu{1 M}$ $\ce{H2SO4}$ solution yields ...
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### How to calculate carbon to phosphorus stoichiometric ratios using results from ICP-MS and CHN analyzer?

I run a few chemostats to manipulate the carbon to phosphorus ratio (C:P) of algae, which is later feed to an invertebrate. I used Inductively coupled plasma mass spectrometry (ICP-MS) and Inductively ...
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### What is the meaning of "maximum" weight produced after series ot reactions?

$4.14$ grams of a piece of lead was made to react with $\ce{HNO3}$ so as to produce lead nitrate. Lead nitrate further reacts with a series of reagents to form $\ce{(NH4)2PbCl6}$. Then find the ...
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### What are some efficient approaches for balancing long chemical equations? [closed]

I am having some difficulties in balancing chemical equations involving many elements. It takes a lot of time (for me) to balance the coefficients using the hit and trial method. Especially like this ...
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### A reaction based question from stoichiometry [closed]

A 110.0g sample of a mixture of CaCl2 and NaCl is treated with Na2CO3 to precipitate the Calcium as Calcium Carbonate. This CaCO3 is heated to convert all the Calcium into CaO and the final mass of ...
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### Why is Fe3O4 a non-stoichiometric compound? [closed]

Fe combines with O in a whole number ratio 3:2. Even the ions Fe2+ and Fe3+ are in the ratio 1:2. Then, why Fe3O4 is a non-stoichiometric compound?
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### How would you find the Q value in the Nernst equation if you were to change the temperature?

I'm studying how changing the temperature of the anode would affect the voltage produced within a galvanic cell. I think that the Nernst equation plays a role here but I am unsure how the reaction ...
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### Finding the molecular formula given combustion data

$\pu{150 cm^3}$ of oxygen were added to $\pu{20 cm^3}$ of a gaseous hydrocarbon D. After explosion and cooling, the gaseous mixture occupied $\pu{130 cm^3}$ and, after absorption by potassium ...
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### Calculate volume of hydrogen gas evolved

MCQ Question: Ammonia borane in water can release hydrogen upon hydrolysis while forming NH4BO2 as the other product. The volume (cm3) of hydrogen gas which will be evolved from the hydrolysis of 309 ...
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### Finding concentration of ascorbic acid

Question: A person applied following procedure for the determination of ascorbic acid (Vitamin C) in a sample solution. A volume of 20.00 cm3 of the ascorbic acid sample was reacted with 25.00 cm3 of ...
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### UV absorbance titration to determine binding stoichiometry

I previously posted a question but I think I did not explain correctly. I want to construct a Job plot using UV-Vis titration to find binding stoichiometry. I have 20uM of ligand solution and 20uM of ...
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### Find percentage of carbon monoxide reacted using ideal gas equation

Question A palladium or platinum catalyst was used in an automobile to convert carbon monoxide gas to carbon dioxide according to the following reaction: $$\ce{2CO(g) + O2(g) -> 2CO2(g)}$$ A ...
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### Calculating required mass of reactant to produce a specific product

I want to know how many grams of $\ce{C}$ (carbon) are required to create $\pu{58 grams}$ of $\ce{Na2S}$, given $$\ce{Na2SO4 + 2C -> Na2S + 2CO2}.$$ First I calculated molecular mass of $\ce{Na2S}$ ...
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### What is mol % and how do you calculate the mass of a compound needed to be a certain mol % relative to another compound at a particular volume? [closed]

I know that there is some stoichiometry involved, but I am lost here. I know you need the molecular weight of both compounds and that's about it?
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### Find the added volume of HCl so that the ions separate

Suppose we have a 10mL solution that contains 0.02M $\ce{Ag^+}$ and 0.04M $\ce{Ba^{2+}}$. a) Find the necessary volume to be added of $\ce{HCl}$ to separate all the silver. (Assume to be separated if ...
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### Does stoichiometric gas mixture produce the highest explosion pressure (or energy) compared with other explosive limit mixture?

I understand that a stoichiometric mixture contains a balanced mixture of air and fuel and both fuel and air are completed consumed. For example, the ideal stoichiometric mixture for propane is ...
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### What's the stoichiometric ratio of Kerosene to a mixture of 50% water and 50% hydrogen peroxide [closed]

So I'm wanting to do some testing with combustion of certain liquids, and I'd like to know what the right ratio is for these liquids. What I'm going to be using is regular kerosene (NOT RP-1) and 50% ...
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### Find the required water volume to add so that the pH of two solutions will be the same

Question. We have two flasks: one contains 50 mL of 0.001 M HCl and the other 50 mL of 1M acetic acid. a) How much water should be added to the more acidic solution so that the pH of the two ...
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### Store Palladium Chloride in Solution

I have one gram of palladium chloride ($\ce{PdCl2}$) and I want to use very small quantities of it, in milligrams somewhere. It is not possible for me to get my hands on a scale that can measure that ...
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### What is the difference between a single displacement reaction and a two competing reaction system?

For example, consider the single-displacement reaction $$\ce{AB + C <=> BC + A}$$ My question is then if writing this reaction as the system \begin{gather} \ce{AB <=> A + B} \\ \ce{B + C &...
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### Balancing a redox reaction equation with a mystery reactant

The answer to the following question from NSAA 2021 Chemistry Section 2 is C. Consider the following chemical equation: $$\ce{vQ + wP4 + x H2O -> yPH4I + zH3PO4}$$ where Q is a binary compound. ...
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### Should durations of time be considered to determine final significant figures of answer?

In preparation for AP Chemistry this upcoming semester I've been assigned a number of challenge problems. One of them is as following: Suppose that polluted air has carbon monoxide $(\ce{CO})$ levels ...
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### Stoichiometric coefficients in reaction between vanadium(II) oxide and iron(III) oxide

Calculate the weight of $\ce{V2O5}$ produced from $\pu{2g}$ of $\ce{VO}$ and $\pu{5.75 g}$ of $\ce{Fe2O3}$ Now we write the reaction as following - $$\ce{2 VO + 3Fe2O3-> V2O5 + 6FeO}$$ Now, by the ...
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### Are chemical equations like a cooking recipe?

Sometimes, balanced chemical equations are compared to cooking recipes. Here is one example: Imagine if you were baking chocolate chip cookies and measured out your ingredients incorrectly. What if ...
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### Difference between change of enthalpy of neutralization between copper and manganese carbonate

I was doing a calorimetry experiment to calculate the change in enthalpy during neutralization reactions between metal carbonates and hydrochloric acid. I experimented with 5 metal carbonates: ...
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### What will be the product of 1 eqv Benzene reacts with 1eqv H2? [closed]

how equivalent concept is applied in the above problem, Kindly help me out with the answer and proper explanation. As, I am getting confused in mole concept and equivalent concept here.
1 vote
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### Finding the density

35.6g of NaOH is dissolved in 150g of 20% NaOH solution. What is the density od the solution? I have tried solving this problem, but I 've come across a few obstacles. Firstly, I found the mass of ...
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### Why is the relationship between a compound in its elements expressed in moles or particles? Is there a law dedicated to this? [closed]

I understand that a ratio can be made for the number of elements in a compound and the actual compound. Depending on the need, different units can be used. It can be both moles. It can also be ...
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### Do you always need to balance a chemical equation to find the percentage yield and limiting reagent?

I'm doing some problems through MIT open courseware and I've got one I'm absolutely stuck on. It details a three-step synthesis for hyperzine A, gives molecular weights and diagrams for individual ...
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### How do you write fractional hydrates in words?

Apart from sequihydrate and hemihydrate (1.5 and 0.5 respectively), I can't find a way to write any other fractional hydrates. Wikipedia states: The notation "hydrated compound⋅nH2O", where ...
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### If sulfur is directly below oxygen on the periodic table, why isn't SO the most common sulfur oxide? Instead of third, behind SO2 and SO3? [closed]

Chalcogen like oxygen and sulfur want to 'grab' (or share) two electrons to get to eight, if possible, or maybe 'give up' (or share) six, if necessary, to again get to eight... Right? So, why is ...
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### Nylon 6,6 synthesis yield

This is the nylon 6,6 reaction Having these data available, I would need to know the theoretical quantities, in grams, of the monomers My attempt: Adipoyl chloride is our limiting reactant so ...
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We provide a reactor $\pu{90 kg}$ of benzene and $\pu{30 kg}$ of $\ce{Cl2}$.If the percent yield of the first reaction with respect to benzene is $25\,\%,$ and the percent yield of the second reaction ...