You will need

- - handle;
- paper for records;
- calculator.

Instruction

1

If you need to calculate the volume percentage

**content**of the substance x, use the formula: CV% = Vx*100/ Vобщ = Vx*100/(Vx+Vy+...+Vn), %;where Vx is the volume of the substance; Vобщ is the total volume, which is the sum of the volumes Vx, Vy,...Vn – component substances.2

To calculate the mass percentage of substance x apply the formula:Cm% = Mx*100/Mobs = Mx*100/( Mx+My+...+Mn), %;where Mx – mass of the substance;Mobs is the total mass, which consists of mass Mx, My,...Mn – component substances.

3

If required to convert volume percentage

**content**in mass, use the relationship: M = V*p, in kg; where M is the mass of matter, kg;V – volume, m3;p – density, kg/m3.4

There are challenges to finding the percentage of a component resulting from mixing two solutions with different concentration.For example, you want to determine the mass percentage

**content of**NaCl in solution obtained by mixing 1 liter of a 10% solution and 2 l of a 20% solution. Density of solutions of 1.07 g/cm3 and 1.15 g/cm3, respectively.5

To solve find the mass of 1l of 10% solution and 2 l of 20% using the formula from step 3. Translate liters to cm3: 1l = 1000см3. You will receive at 1.07 kg and 2.30 kg. Fold both the masses and get a lot of mixed solution of 1.07+2,30 = 3.37 kg

6

Converting the formula from step 2, find the mass of NaCl in the first and second solution: Мсоли1 = 1,07*10/100 = 0,107 kg. Мсоли2 = 2,30*20/100 = 0,460 kg. Fold the masses and get a lot of salt in the resulting solution: 0,107+0,460 = 0,567 kg. By the formula from step 2, find the percentage

**content**of salt in the mixture of solutions: 0,567*100/3,370 = 16,83 %.# Advice 2: How to calculate percentage

One-hundredth of a whole is called the percentage. If this integer value is composed of several separate parts, each of them can be measured in hundredths of the whole.

**The ratio**of the magnitudes of these components will be called a percentage. Practical calculation it is not difficult and consists of several simple mathematical operations.Instruction

1

Find out what the values should be based on the expectation value of one percent. For example, if a drug consists of two ingredients, three-dimensional characteristics are known, then the whole should be the sum of these two known values and calculate the value of one percent, dividing that amount into one hundred parts. For example, if ready to eat the paint contains eight hundred milliliters of the actual paint and four hundred milliliters of solvent, then the one percent will be expressed the value of twelve ounces, as (800+400)/100=12.

2

Find the percentage expression of each of compared values, dividing the value of each of the components of the integer values calculated in the previous step size one percent. For example, the amount of dye in solution from the example in the previous step will be about 67 percent, as 800/12=66,6666667. And the volume of solvent of the same example is equal to approximately 33 percent, so 400/12=33,3333333. These two numbers will Express the percentage of the components of ready solution components.

3

Use for calculations, for example, built into the Windows operating system software calculator, if you calculate values in mind is not possible. To access this application through a standard dialog box run programs by calling it by pressing shortcut keys win + r.

4

In dialogue it is necessary to type the command calc and click on the "OK" button. The calculator interface is extremely simple, and the sequence of several operations of division and multiplication, as described in the previous steps, is unlikely to cause any difficulties.

# Advice 3: How to find the percentage concentration

Concentration is the value which characterizes the qualitative composition of the solution. Concentration is called the number of the solute or its mass to the total volume or mass of fluid. Thus, the most important characteristics are the mass and volume fraction.

You will need

- - the mass of the solute;
- - the mass of the solution.

Instruction

1

Mass fraction, it is the same percentage concentration is a dimensionless quantity, which is equal to the ratio of the mass solute to the total weight of the liquid. Most often it is expressed as a percentage, which you multiply the resulting ratio by one hundred. Formula percentage

**concentration**can be recorded in the following way: ω = m in-VA/m R-RA*100%. The first value is the mass of the substance, and the second mass of the solution as a whole.2

Often in the task given percentage concentration of a substance, based on which you want to find the mass of substance / mass of solution. It is very simple, just need to convert the original formula. To find the mass of a substance it will be as follows: m VA = m R-RA* ω/100. The mass of the solution can be found as follows: divide the mass of the substance in percent

**concentration**and then multiply the result by one hundred. The unit mass of a substance and the mass of solution – grams.3

To find the percentage concentration if the solution was obtained with the use of hydrated, you should use a different solution algorithm. The crystalline has the structure of IU(x)-TA(y)*nH2O. In the problem statement, which appears as a crystalline, should contain information about the mass of the hydrated and the dry mass metal-x-acid-y. In this case, the percentage concentration will be equal to the mass of the solution multiplied by the molar mass of hydrated divided by mass of crystalline, multiplied with the ratio dry substance and the molar mass of the anhydrous substance.

Useful advice

Counting the weight of the solution, note that it consists of two quantities: the mass of solvent and mass of a substance dissolved in it. The omission of this fact is a large number of errors during these tasks.

# Advice 4: How to calculate density

**Density**is one of the characteristics of matter, such as mass, volume, temperature, area. It is the ratio of mass to volume. The main task is to learn how to calculate this value and know what it depends on.

Instruction

1

**The density**of a substance is numerically the ratio of mass to volume of a substance. If you want to determine the density of a substance and you know its mass and volume, finding the density will not make you work. The easiest way to find the density in this case is p = m/V. It is measured in kg/m^3 in SI units. However, not always a given these two values, so you should know some ways by which you can calculate the density.

2

**The density**has different values depending on the type of substance. In addition, the density changes from salinity and temperature. With decreasing temperature, the density increases, and with the lowering of the degree of salinity decreases and the density. For example, the density of the red sea is still considered high, and in the Baltic sea it is already less. All of you have noticed that if the water to fuel, it POPs up. All this is due to the fact that oil has a lower density than water. Metals and stone substances, on the contrary sink because their density is higher. On the basis of the density of bodies there was a theory about their swimming.

3

Thanks to the theory of the swimming of bodies there was a formula that I can find the density of a body, knowing the density of water, the volume of the body and the volume of its immersed part. This formula has the form:Vпогруж. part / V of the body = p / p liq.It follows that the density of the body can be found as follows:R body = V submersible. parts * fluid R / V body.This condition is satisfied on the basis of the tabular data and the given volume V submersible. part V of the body.