# Problem Solving Rubric (UDRSS)

As derived by the OHHS 2006 Chemistry Collegial teamWeight | 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.

- Units: Does every number in the problem below have the appropriate units?
- Data
- Distance = 180 miles
- Time = 4 hours

- Relationship: Velocity = Δ distance / Δ time
- Substitute: Velocity = 180 miles / 4 hours
- 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?

- Units
- Does every number in the problem below have the appropriate units?

- Data
- Silver density = 10.5 g/ml
- Silver sample = 5.25 g
- beginning water volume = 11.2 ml

- Relationship
- Final volume = initial volume + volume of silver
- density = mass / volume
- Solving d=m/v for volume: v = m / d

- Substitute
- final volume = 11.2 ml + (5.25g / 10.5 g/ml)
- final volume = 11.2 ml + 0.5 ml

- Solve
- final volume = 11.7 ml