Chemistry of Life Lab

A flat (2D) toy model: molecules jiggle faster as you heat them, turn a hydrogen toward a neighbour's oxygen, and hydrogen bonds form or break. A flat drawing allows fewer hydrogen bonds than real 3D water (about 3.4 per molecule at 25 °C), and the drawn ice expands more than the real 9%. The density curve uses measured values for real water. Motion is slowed down by about a trillion times.

pH is solved exactly from a charge balance, using a carbonic acid pKa of 6.1 (the value used for blood, which counts dissolved CO₂), 10.3 for bicarbonate and water's ion product of 1.0 × 10⁻¹⁴, so pure water starts at pH 7.00. The buffered beaker starts like blood plasma: 24 mM bicarbonate and 1.2 mM carbonic acid. "Lungs on" holds carbonic acid at 1.2 mM by breathing extra CO₂ away (an open system). Each portion adds 1 mM of strong acid (HCl) or base (NaOH). Proteins and phosphate buffers are left out. The particle view uses a log scale for H⁺.

Problems are randomly generated. The picture responds to the answer you type, then shows the worked solution line by line.