Mastering Chemistry Answers

Problem solving is an important part of chemistry. Problem solving is like learning to swim or play a musical instrument; it becomes easy only with practice.

Chemistry builds one concept on another and fact on fact. The secret of mastering chemistry answers is to know how to approach a new problem and how to put the pieces together.

The seven steps of scientific problem solving are as follows.

1. Identify the problem
2. Gather information relative to the problem.
3. Formulate tentative solutions (hypotheses)choose proffered solution.
4. Plan action to test suggested solution.
5. Experiment and observe the results.
6. Interpret the results (draw conclusion) understand what the results mean.
7. Evaluate the solution either concluding or revising the study to test the solution again if results are are unsatisfactory.

The use of complicated mix of inquiry, knowledge, intuition, logic, experience and common sense called critical thinking. The following are the steps should be taken care when a problem is solved.

• Read the problem carefully.
• Plan in detail just how the problem is to be solved.
• Specific definitely what each number represents and the units in which it is expressed when the mathematical operation is carried out.
• Having solved the problem examine the answer to see if it is reasonable and sensible.
• If the problem is not understood have it explained to you at the very earliest possible time.

Mastering Chemistry Help

Much of chemistry is concerned with the applications of concepts to practical problems.

Example

When 2.53 grams of metallic mercury is heated in air, which produces 2.73 grams of a red orange residue. Assume that the chemical change is the reaction of the metal with oxygen in air

Mercury + oxygen → red-orange residue

what is the mass of oxygen that reacts? When the red-orange residue is heated it decomposes to give back the mercury and release the oxygen when it is collected. What is the mass of collected oxygen?

Problem strategy

Apply the law of conservation of mass to the reaction.According to this law, the total mass remains constant during a chemical reaction; that is

mass of substance before reaction = mass of substance after reaction

Solution

From the law of conservation of mass

Mass of mercury + mass of oxygen = mass of red-orange residue

Substituting the values
2.53 grams + mass of oxygen = 2.73 grams
or
mass of oxygen = (2.73 - 2.53)grams
= 0.20grams

The mass of oxygen collected when the res-orange residue decomposes equals the mass of oxygen that originally reacted.