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High School (11–12) · Chemical Bonding
You will write three functions that do the counting behind a Lewis structure. The idea. The total adds the valence electrons of all atoms and corrects for the charge. A central atom joined to halogens by single bonds…
StemPy LabHigh School (11–12) · Chemical Bonding
You will compare measured dipole moments of gas-phase molecules with the dipoles they would have if fully ionic. The idea. A charge e on each atom at a distance d gives μ = e × d. Divide by 3.336 × 10^-30 C m to get d…
High School (11–12) · Chemical Bonding
A dictionary links each pair of numbers, electron pairs and lone pairs, to the name of a shape. You will count the pairs on the central atom of sulphur tetrafluoride, find its lone pairs, and look up its shape. The id…
High School (11–12) · Chemical Bonding
Six molecules are stored with the outer electrons of their central atom and the number of singly bonded atoms. You will find the electron pairs on each central atom, its hybridisation, and the molecules that keep a lo…
High School (11–12) · Chemical Bonding
The molecular orbitals of a diatomic molecule are stored in a list, from the lowest energy up, with how many electrons each holds and whether it is bonding. You will write a function that fills them with a given numbe…
High School (11–12) · Chemical Bonding
The boiling points of the hydrides of groups 15, 16 and 17 are stored in three lists, from period 2 to period 5. In each group, the hydride of period 2 can form hydrogen bonds. You will find how far it stands above th…
High School (11–12) · Chemical Bonding
You will write two functions that add bond dipoles, then use the idea of full charges to find how ionic a bond is. The idea. Two equal bond dipoles at an angle θ add to 2μ_b(θ)/(2). In a flat molecule, each bond dipol…
High School (11–12) · Chemical Bonding
You will write a formal charge function, add up the sizes of the charges, and use them to choose the best Lewis structure of the phosphate ion. The idea. Formal charge = V - L - B. The best structure has the smallest…
High School (11–12) · Periodic Trends
The radii of the period 3 atoms are stored in a dictionary. You will find the largest atom, list the elements from the smallest to the largest, and work out how much the radius falls across the period. The idea. Acros…
High School (11–12) · Periodic Trends
The successive ionisation enthalpies of an element show how many electrons it holds loosely. You will find the ratio of each enthalpy to the one before, the number of valence electrons, and the group of the element. T…
High School (11–12) · Development of the Periodic Table
You will write the two functions that give the temporary IUPAC name and symbol of an element from its atomic number. The idea. Join the roots of the digits and add ium. The i of bi and tri is dropped before ium, and t…
High School (11–12) · Development of the Periodic Table, Groups and Families
You will fill the subshells in the Aufbau order and read where an element sits in the long form, for atomic numbers up to 54. The idea. The period is the highest shell with electrons. The block is the last subshell fi…
High School (11–12) · Stoichiometry and Concentration, Molecules, Ions and Formulae
Every compound has a fixed composition by mass. You will find the molar mass of ammonium phosphate, a fertiliser, from its formula, then the mass percent of each element, and the element with the largest share. The id…
High School (11–12) · Stoichiometry and Concentration, The Mole Concept
Marble chips react with hydrochloric acid: CaCO_3 + 2HCl → CaCl_2 + H_2O + CO_2. You start with 25 g of marble and 14.6 g of hydrogen chloride. You will find the limiting reagent, the carbon dioxide formed and what is…
High School (11–12) · The Mole Concept, Molecules, Ions and Formulae
Chromium has four isotopes. You will check that their shares add up, find the average atomic mass, and pick out the most common isotope. The idea. A = Σ mass × share100, with the shares in percent. Your tasks. Set tot…
High School (11–12) · The Mole Concept
Four gases are weighed out, 10.0 g of each. You will write a function for the molar mass from the formula, a function for the number of molecules, and then find the sample with the most molecules. The idea. M is the s…
High School (11–12) · Measurement, Units and Significant Figures, Elements, Compounds and Changes
Four objects are weighed and their volumes are measured. You will find the density of each, the ones that float in water, and the densest one. The idea. d = (m)/(V). An object floats in water when its density is less…
High School (11–12) · Measurement, Units and Significant Figures
Python's round(x, n) rounds to a number of decimal places. A chemist often needs a number of significant figures instead. You will write a function for it, and use the rules for products and sums. The idea. The first…
An electron configuration explorer Chemistry
High School (11–12) · Electronic Configuration and Valency, Quantum Mechanical Model of the Atom
The filling order, Hund's rule and the spin-only formula fit in a few lines of code. You will sort the subshells into filling order, count unpaired electrons, and find the magnetic moment of an ion. The idea. Subshell…
The wavelength of a moving electron Chemistry
High School (11–12) · Quantum Mechanical Model of the Atom
An electron speeded up through a voltage V has p = √(2m_e eV). You will find its de Broglie wavelength for several voltages and the first voltage at which it becomes shorter than the Bohr radius. Then the program draw…
The photoelectric effect for five metals Chemistry
High School (11–12) · Light, Atomic Spectra and the Bohr Model
Five metals have different work functions. You will find the photon energy of a light, the greatest kinetic energy it gives each metal, and which metals give electrons at all. Then the program draws the result. The id…
Drawing the lines of hydrogen Chemistry
High School (11–12) · Light, Atomic Spectra and the Bohr Model
Rydberg's formula gives every line of hydrogen. You will write it, list the first lines of a series, and pick out the Balmer lines that the eye can see. Then the program draws them. The idea. (1)/(λ) = R_H((1)/(n_1^2)…
The mass spectrum of chlorine gas Chemistry
High School (11–12) · Isotopes and Isobars, Subatomic Particles and Atomic Models
A Cl_2 molecule is made of two chlorine atoms, each 35 or 37. You will work out the share of each kind of molecule, the average molar mass of the gas, and the tallest peak. Then the program draws the spectrum. The ide…
How close can an alpha particle come? Chemistry
High School (11–12) · Subatomic Particles and Atomic Models
An alpha particle heads straight at a nucleus and stops for a moment at its closest approach. You will compute that distance and the radius of the nucleus, and find which nuclei a fast particle actually reaches. The i…
Will the halogen displace? Chemistry
High School (9–10), General · Groups and Families
A more reactive halogen pushes a less reactive one out of its salt. You will write the test, name what is set free, and list every pair that reacts. The idea. The order, most reactive first, is F, Cl, Br, I. A free ha…