Planning problems
Why is constructing a plan for solving a problem important?
Analysing problems before entering numbers into your calculator takes time at the beginning, but you will discover that many problems are similar, and analysing a set of problems will ultimately make solving any problem easier.
What is a plan?
A plan is a roadmap between the Known quantities and the Unknown quantity.
Plans use symbols for given and unknown quantities.
Plans show symbols for intermediate quantities that need to be calculated.
Symbols for quantities used in chemistry problems are shown at the right.
See below an example problem with a plan of the type that you will construct on the BestChoice pages.
Example:
21.21 of aqueous HCl reacts with 0.130 g Na2CO3 according to the reaction shown below.
What is the concentration of HCl in the solution?
Na2CO3(aq) + 2HCl(aq)
2NaCl(aq) + H2O + CO2(g)
Once the links between the known and the unknown are clear, you will also add above the arrows relationships required to do the calculations shown in each step.
Analysing problems before entering numbers into your calculator takes time at the beginning, but you will discover that many problems are similar, and analysing a set of problems will ultimately make solving any problem easier.
What is a plan?
A plan is a roadmap between the Known quantities and the Unknown quantity.
| quantity | symbol |
| mass | m |
| volume | V |
| concentration | c |
| amount in moles | n |
Plans show symbols for intermediate quantities that need to be calculated.
Symbols for quantities used in chemistry problems are shown at the right.
See below an example problem with a plan of the type that you will construct on the BestChoice pages.
Example:
21.21 of aqueous HCl reacts with 0.130 g Na2CO3 according to the reaction shown below.
What is the concentration of HCl in the solution?
Na2CO3(aq) + 2HCl(aq)
2NaCl(aq) + H2O + CO2(g)| m(Na2CO3) Known | Step 1 | n(Na2CO3) | Step 2 | n(HCl) | Step 3 | c(HCl) Unknown |