Problem Solving Rubric (UDRSS)

As derived by the OHHS 2006 Chemistry Collegial team
Weight Category Description
1 Units Units are used correctly throughout the problem.
1 Data All known and unknown variables are listed. When appropriate, a sketch of the physical situation that shows all elements involved in the problem is included.
1 Relationship The correct function, equation, or definition is identified to connect known variables to unknown variables.
1 Substitute All symbols are replaced with known values
1 Solve Numerical values are correct.

Sample problem 1:

Find the velocity of a car that travels 180 miles in 4 hours.

  1. Units: Does every number in the problem below have the appropriate units?
  2. Data
    • Distance = 180 miles
    • Time = 4 hours
  3. Relationship: Velocity = Δ distance / Δ time
  4. Substitute: Velocity = 180 miles / 4 hours
  5. Solve: Velocity = 45 miles/hr

Sample problem 2:

Pure silver (Ag) has a density of 10.5 g/ml. A 5.25 gram sample of silver is placed into a graduated cylinder that contains 11.2 ml of water. What will the final volume of the water read?

water displacement graduated cylinders
  1. Units
    • Does every number in the problem below have the appropriate units?
  2. Data
    • Silver density = 10.5 g/ml
    • Silver sample = 5.25 g
    • beginning water volume = 11.2 ml
  3. Relationship
    • Final volume = initial volume + volume of silver
    • density = mass / volume
    • Solving d=m/v for volume:     v = m / d
  4. Substitute
    • final volume = 11.2 ml + (5.25g / 10.5 g/ml)
    • final volume = 11.2 ml + 0.5 ml
  5. Solve
    • final volume = 11.7 ml