Instruction

1

Remember the multiplication table, if there is no auxiliary computational tools, but there is a need to calculate the square of any number. If this can be done, multiply in the mind or on paper (in a column) you are interested in the number itself. This method of computing nowadays, perhaps, be attributed to the category of intelligent entertainment or gymnastics for the mind, as it is neither the fastest nor the simplest.

2

Use the search engine Google or Nigma, if computational tools are not in your possession, but have access to the Internet. There is no need something to search for in these search engines - they are calculators. Simply enter a relevant query and get the already calculated result. For example, to know the value of the squared number of 5.47 send to the server a search engine query 5,47*is 5.47, or 5, 47^2, or "5,47 squared" - in each case, the search engine will show you the correct answer (29,9209).

3

Run the program simulates an ordinary calculator, if described in the previous two steps ways for some reason unavailable. This program is part of the standard Suite of applications installed with the operating system. In Windows any version you can open it using the standard dialog run programs called on the screen by simultaneously pressing Win key and R. the only field of this dialog, type calc and press Enter.

4

Enter the number whose square it is necessary to calculate - just enter it on the keyboard or click the appropriate buttons in the calculator interface. Then type the command multiplication - press the asterisk or click on the same button in the interface. To enter the second times the number required, just press Enter and the calculator will display the result of multiplying the number by itself.

# Advice 2: How to calculate the degree of dissociation

**The degree**

**of dissociation**is the amount equal to the ratio of the number of molecules that split into ions, to the total number of molecules of the substance in solution or the melt.

Instruction

1

Say you have set such a task. A solution of ammonia with concentration of 0.1 M. the results of laboratory tests you know that medicationabana concentration of alcohol molecules is equal 0,099 mol/liter. What will be the degree

**of dissociation**?2

First of all, recall the definition of the degree

**of dissociation**and the formula by which it is calculated: a = n/n, where n is the number of molecules of substances that split into ions, and N is the total number of molecules of a substance.3

Then write the equation of the electrolytic

**dissociation**of ammonia, it will look like the following:NH4OH = NH4+ + OH-4

The conditions of the problem known initial molar concentration of alcohol. Label it with the letter C. Then the concentration of alcohol molecules undergoing

**dissociation**, label as as. Accordingly, the concentration of ions NH4+ and OH - will also be equal to this value, that is AC.5

Determine what is the value of AC. It is easy to see that 0.001 mol/liter (you will receive this value, subtracting from the initial concentration of total alcohol concentration of undecayed molecules). Consequently, the desired value is: 0,001/0,1 = 0,01. The problem is solved.

**The degree****of dissociation**of ammonia under specified conditions equal to 0.01 (or 1% in another year).Note

Try to remember this simple rule: the closer the degree of dissociation is close to unity (or 100%), the stronger the electrolyte the closer to zero the less.

Useful advice

If a strong electrolyte, the dissociation is exposed to a significant portion of its molecules (in some cases, almost all). Accordingly, the weaker the electrolyte, the smaller the number of molecules breaks up into ions. The criterion for assessing the strength of the electrolyte is the degree of dissociation.