Final answer:
A cell with 100 mosm calcium chloride outside and 150 mosm sodium chloride inside will experience water movement due to osmotic pressure. Calcium contributes more to osmolarity because each molecule provides three particles, meaning the outside solution is hypertonic, causing the cell to potentially crenate.
Step-by-step explanation:
A cell with 100 mosm calcium chloride (CaCl2) on the outside and 150 mosm sodium chloride (NaCl) on the inside will experience an osmotic pressure gradient due to the difference in milliosmolarity (mosm) across the cell membrane. The cell membrane is selectively permeable, allowing some ions and molecules to pass through while restricting others. In the case of calcium chloride and sodium chloride, the cell will tend to maintain an electrochemical balance, where the overall charge inside the cell is equal to the outside.
Given that calcium has a charge of +2 and forms ions more easily due to its position in the periodic table, the calcium ions (Ca2+) will contribute twice to the osmolarity for every molecule dissociated, whereas sodium and chloride ions contribute once each per molecule dissociated. This means that 100 mosm CaCl2 is equivalent to 200 mOsm in terms of particles, because each CaCl2 provides three particles (one Ca2+ and two Cl-).
Based on the information provided, the inside of the cell with 150 mosm NaCl has fewer total dissociated particles than the outside with 100 mosm CaCl2 (which actually represents 200 mosm when accounting for ion dissociation). If the cell membrane is permeable to water but not to these ions, water will move by osmosis from the inside of the cell to the outside, potentially causing the cell to shrink or crenate, as it is in a hypertonic solution relative to the inside of the cell.