Chemistry Problem Solver

Chemistry Problem Solver

One of the great joys of studying chemistry is learning to be a good problem solver. The ability to solve complicated problems is a skill which will help greatly throughout life.The basic steps in solving problems are.

1. Read: Read the problem carefully. Determine what is known and what is to be solved for and write them down. It is important to label all factors and measurements with the proper units.
2. Plan: Determine which principles are involved and which unit relationships are needed to solve the problem.
3. Setup: Set up the problem in a neat, organized and logical fashion, making sure all unwanted units cancel. Use the examples as guides for setting up the problem.
4. Calculate: Proceed with the necessary mathematical operations. make certain that the answer contains the proper number of significant figures.
5. Check: Check the answer to see if it is reasonable.

During problem solving should not allow any formal method of problem solving to limit the intuition. If a problem is clear and the solution seems to be simple by any other method by all means use it.

Chemistry Practice Problems

Calculate the specific heat of a solid in J/g^oC and cal/g^oC if 1638J raises the temperature of 125g of the solid from 25.0^oC to 52.6^oC.

Solution

1. Read:
Known 125g of the solid
Δt = 52.6 - 25.0 = 27.6^oC
Heat = 1638 J
Solving for: Specific heat of the solid

2. Plan:

Use the equation
(mass)(Specific heat)(t) = heat
solving for specific heat

3. Setup:

Specific heat = heatg×△t

4. Calculate:

Specific heat = 1639J125g×27.6oC = 0.475J/g^oC

Convert joules to calories using 1.00cal4.184J

specific heat = (0.475JgoC)(1.000cal4.184J) = 0.114cal/g^oC

5. Check:

Note that the units on the answer agree with the units for specific heat.