Questions tagged [numerical-analysis]
The numerical-analysis tag has no usage guidance.
20
questions
3
votes
1answer
38 views
Calculating the total uncertainty of the final product
I have performed a large number of calculations in order to determine the ethanol content of wine. These included titrations using burettes, mass measurements using analytical balances, and others. I ...
6
votes
4answers
619 views
accurate measurement from inaccurate tools [closed]
It is a very general question. Is there a good way to systematically increase the accuracy and precision of a measuring tool using only mathematical means? For example, average 10 measurements can ...
1
vote
1answer
58 views
Balancing chemical reactions, issues of Gauss's elimination method [duplicate]
I am trying to balance some chemical reactions by using the Gauss' elimination method and I noticed that this method does not work if the creation of a matrix with exactly one degree of freedom is not ...
4
votes
0answers
57 views
Factorizing Slater determinant into product of spin-up and spin-down slater determinant
I am reading the book on MONTE CARLO METHODS IN AB INITIO QUANTUM CHEMISTRY by Hammond and Lester. (Chapter 5-Variational Trial Functions, Section 5.3-Hartree Fock and Beyond, Sub-Section 5.3.3 ...
3
votes
0answers
137 views
Good software/module in python to determine nuclear attraction integral in Slater type orbital basis sets
I am trying to solve a Hamiltonian of one electron and 10 stationary nuclear centers. here, the electron is treated quantum mechanically and nuclear centers are treated classically objects. The ...
2
votes
1answer
74 views
what is the issue in evaluating two electron integral?
What sort of issue is there in two electron integral in quantum chemistry ? Is it a problem of convergence when we do numerically? Can someone suggest any review article or reference articles which ...
-2
votes
1answer
297 views
Chemistry - Solutions
Please give me a few hints as to how I can approach this problem
A mixture of two miscible volatile ideal liquids P and Q (obeying Raoult’s law) is kept in a vessel (molar ratio of P and Q in the ...
3
votes
0answers
41 views
Limit to volume change in a discretized mathematical model?
I have set up a mathematical model describing the diffusion of ozone out of a gas bubble. The bubble is surrounded by a thin gas film. So actually, the model describes the diffusion of ozone through ...
2
votes
1answer
80 views
Current in a Concentration Cell
I would like to know if there is a simple function that gives the current as a function of time in a concentration cell. The current is measured in the wire connecting the two terminals of the cell. ...
3
votes
1answer
165 views
How to numerically solve a reaction network with fast equilibrium steps?
For example If I have to solve the following reaction numerically
\begin{align}
*\ce{ + A(g) &<=>[K1] [A*]} \tag{1}\\
\ce{[A{*}] &<=>[k1][k-1] [B{*}]} \tag{2}\\
\ce{[B*] &&...
0
votes
1answer
2k views
How to round correctly when calculating the average and standard deviation?
Is my Chemistry book wrong on the significant figures in this exercise?
Why did they round to 0.16 instead of 0.1580 ?
Also why did they round down the means?
0
votes
1answer
1k views
Find molar concentration of sodium carbonate dissolved in water
The question is
A solution of $\ce{Na2CO3}$ is made by dissolving $5.3~\mathrm{g}$ of the powder in enough water to make $250~\mathrm{mL}$ of solution. Find the molar concentration.
I have done ...
4
votes
4answers
2k views
Does the addition or multiplication rule have precedence deciding the significant figures in 5×5.364? [duplicate]
How many significant figures should be present in the answer of
$5\times 5.364$?
Addition rule: The result cannot have more digits to the right of the decimal point than either of the original ...
1
vote
1answer
1k views
the number of significant figures
An electronic balance was used to determine that a sample has a mass of 9.00060 g. If the balance's precision is ± 1 mg, what is the correct number of significant figures for this measurement?
...
0
votes
1answer
132 views
How to calculate concentrations and what is the concept of 'mole'?
Say I have a $50~\mathrm{ml}$ solution of a liquid mixture which is $30~\%$ concentrated. Now if I take $20~\mathrm{ml}$ of that liquid out from that mix, what would be the resulting concentration of ...
2
votes
0answers
59 views
How to define a flame in numerical combustion?
I am running a CFD simulation (computational fluid dynamics) opposed jet case, where a stream of fresh reactants is opposed to a stream of burnt products. I am looking at the effects of stratification ...
1
vote
1answer
1k views
Propagation of the uncertainty in measurements
The inside dimensions of a box that is cubic is 12.7 cm on each edge with an uncertainty of 0.3 cm.
What is the volume of the box?
What do you estimate to be the uncertainty in the ...
0
votes
1answer
5k views
Convert grams of water to steam
I'm working through problems in my textbook. How much heat is required to convert 2.55 g of $\ce{H2O}$ at 28 °C to steam at 100 °C?
In simpler problems I've used the fact that $\Delta H_\text{fus} = ...
5
votes
1answer
4k views
Calculate the number of moles produced per hour per liter of air?
A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by
$$
\ce{O3(g) + NO(g)->O2(g) + NO2(g)}
$$
the rate law for this reaction is:
$$
\text{...
10
votes
1answer
27k views
How do I round a calculation involving both addition/subtraction and multiplication/division to the correct number of significant figures?
I'm just learning about significant figures (sig figs) in my chemistry class, and I'm confused about the rules. An example to my problem: if I had the following expression:
$$\left ( \frac{2.378 - 1.2}...
