4 original questions from New Regents. The worksheet, answer key, and browser practice are free.
Checking Reaction Contacts in Divided Cells 4 questions
Checking Reaction Contacts in Divided Cells
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A reaction display has two equal compartments separated by a wall. Particles cannot cross the wall. One A and one B must meet in the same compartment for a reaction. In the model, the initial contact index in a compartment equals its A count times its B count. The whole display adds the two local indices.
| Run | Left counts (A, B) | Right counts (A, B) |
|---|---|---|
| P | 4, 4 | 4, 4 |
| Q | 8, 0 | 0, 8 |
| R | 6, 2 | 2, 6 |
Question 1
Which run has no initial A–B contact in either compartment?
- P
- Q
- R
- All three
Question 2
Calculate and compare the whole-display contact indices for P and R.
Write your answer and work on the printable worksheet, or answer online.
Question 3
A student calculates 8 × 8 = 64 for all three runs. Explain what contacts this counts incorrectly.
Write your answer and work on the printable worksheet, or answer online.
The display opens the wall in Q and quickly mixes the particles evenly across the same combined volume before measuring.
Question 4
Predict which earlier local count pattern now fits Q if the display divides the mixed space into two equal halves.
Write your answer and work on the printable worksheet, or answer online.
2025 Chemistry Reference Tables · Browse Chemistry worksheets