sxyu / hexane

An online calculator that supports calculations with significant figures. Designed for use by chemistry students and has an equation balancer, a molar mass calculator, etc. Math input field powered by MathQuill.

Hexane

hexane.cf

Reuse My Code

All code in this project is licenced under the Apache License, version 2.0. The reusable javascript files are available as a release. Check out the releases page for more information about usage.

Overview of reusable JS files:

• signum.js JS numbers supporting all sorts of computations with significant figures
• hexane.eval.js JS LaTeX math evaluator for use with MathQuill. Created with Jison.
• hexane.eval.signum.js Same as above, but does computations with SigNums instead of regular numbers.
• hexane.balance.js Powerful & fast JS equation balancer supporting charges, nested brackets, etc.

Hexane is an online calculator supporting calculations with significant figures. It is designed for use by chemistry students and contains many additional features such as an equation balancer to facilitate learning. The basic design is very simple and intuitive. Features are outlined below.

Basic Usage

• To use the calculator, open hexane.cf on any computer or mobile device
• Type into the calculator textbox to evaluate any expression
• The result is displayed at the top both as a full number and in scientific notation
• On mobile devices and other devices with touch screens, you may want to use the keypad below to enter expressions.
• Most of the data in the calculator is stored in your browser. When you refresh the page the content in the textbox remains and variables and saved results persist. Note that if you clear your cookies/site data, this data may be deleted as well.

Typing Math

Hexane uses MathQuill: github.com/mathquill/mathquill to accept mathematical input.

• Typing + - and * will give you the addition, subtraction, and multiplication operators, respectively.
• Typing / allows you to insert a fraction
• Typing ^ creates an exponent
• Typing _ creates a subscript
• Typing log_ allows you to create a log expression
• E raises a number to a power-of-ten
• % is the percent operator
• ( ) [ ] { } are all valid brackets operators
• < > = <= >= are comparison operators

Special Characters in the Hexane Calculator

• # Marks a number as infinitely precise: #1 / 100. = 0.0100
• " Marks the start & end of chemical formulae: "H2O"

Memory Module

Hexane allows you to store values in variables so you can use them again later. These are saved in your browser and persist between sessions.

• Left click one of the memory tiles (below the keypad) to enter the letter into the textbox.
• Right click to save the current result in the calculator to the specific variable.
• The := operator Allows you to assign variables: a := 3

Saved Results Module

Another way to reuse answers is to save them to the "saved result" module.

• Press Enter in the textbox to save the current result
• You may also press Save on the keypad to save the current result.
• Press on any of the saved result tiles (the saved result module is below the memory module) to enter the tile's stored value into the textbox. Right click or press the delete button on any one of the tiles to delete it.
• Press the clear button to delete all the tiles.

Chemistry-Related Functions

Hexane provides a number of built-in chemistry-related functions. To use them, enter the function name, type (", enter the chemical formula as appropriate, and then close off the formula with "). The brackets (()) enclose the function parameters whereas the quotes ("") mark the chemical formula. You may choose to use subscripts in the chemical formulae (H₂O instead of H2O) but are not required to.

To enter a chemical formula on a mobile device, it may be more convenient to use the periodic table keyboard (open with the He key on the keypad).

Usage Example: Ka("CH3COOH")

Here is a list of all the available functions:

• Ka pKa Kb pKb Ksp: Get the respective data value for a compound
• elemmass: Get the molar mass of an element (you may want to use molmass instead)
• molmass: Calculate the molar mass of a compound
• balance: Balance a chemical equation of the form A ... B = C ... D. Try: "K4[Fe(SCN)6]+K2Cr2O7+H2SO4=Fe2(SO4)3+Cr2(SO4)3+CO2+H2O+K2SO4+KNO3"
• charge: Get the common charges associated with an elemental or polyatomic ion.
• qdtcacid: Takes a Ka and a concentration and outputs the correct [H3O+]

The following are not strictly chemical functions but are still often useful in chemical calculations:

• sf: Get (sf(3.0)) or set (sf(300,2)) the number of significant figures in a number.
• qdtc: Takes three parameters a, b, c and outputs the solution(s) to the quadratic equation ax^2 + bx + c = 0.
• qdtcp qdtcn: only return at most one of the two possible qdtc solutions to produce a numerical result you can work with.

License

This project is licensed under the Apache License 2.0 available here: http://www.apache.org/licenses/LICENSE-2.0

For details, please refer to the LICENSE.md file under the project root directory.