You will need

- - hydrometer;
- - table of densities substances;
- - scales;
- - measuring cylinder.

Instruction

1

To measure the density of the liquid

**mixture**, take a hydrometer. Soak it in liquid so that it freely floated in it. At the top of the hydrometer is a scale. Determine**the density****of the mixture**, combining the scale with the bottom edge of the meniscus of the liquid in which it is immersed.2

To calculate the density

**of the mixture**weigh her on the scales. The value of the mass m will get grams. Using the graduated cylinder, or other means, determine the amount of weighted number**of compound**V. the Measurement are produced in cm3. Calculate**the density****of the mixture**, dividing its mass by the volume ρ=m/V. the Result is in g/cm3. In order to convert it in kg/m3, multiply the result by 1000.3

Primeri melting the two metals received 400 g of alloy, with a volume of 50 cm3. Determine its

**density**. Calculate the density according to the formula ρ=400/50=8 g/ cm3 or 8000 kg/m3.4

If you know the density of the substances to be mixed, and their amounts, as often occurs when mixing the liquids, calculate

**the density of**the resulting**mixture**. Measure the volume**of the mixture**. It may differ slightly from total volume of mixed liquids. For example, when mixing 1 liter of alcohol and 1 liter of water the volume**of the mixture**is less than 2 liters. This is due to the molecular structure of these two liquids.5

If the density of the miscible fluids is unknown, find their value in the special table. To calculate, find the sum of the products of the density of each of the liquids on its volume ρ1∙V1+ ρ2∙V2+ ρ3∙V3+... etc the resulting value divide by the total volume

**of the mixture**V, ρ=(ρ1∙V1+ ρ2∙V2+ ρ3∙V3+...)/V.6

Primeri mixing 1 liter water and 1 liter of ethyl alcohol received 1.9 l

**of the mixture**. Determine its**density**. The density of water is 1 g/ cm3, alcohol 0.8 g/cm3. Put the units of volume: 1 l=1000 cm3 and 1.9=1900 cm3. Calculate**the density****of the mixture**using the formula for two components ρ=(ρ1∙V1+ ρ2∙V2)/V=(1∙1000+ 0,8∙1000)/1900≈0,947 g/cm3.# Advice 2: How to find mass if the volume and density

The mass of a body is its most important physical characteristic. In modern physical science, there is a distinction between the concepts of "mass" gravitational mass (as the degree of impact of a body on the earth's gravity) and inertial mass (how much effort will be required in order to bring the body from a state of inertia). In any case, to find

**the mass**very easily, if you know**the density**and volume of the body.Instruction

1

In that case, if the body is known to such indicators as the volume (V) and

**density**(p) for calculating the body mass will need to use the formula: m = p*V.2

For clarity, you can give an example. You want to find

Solution: for finding the mass of the concrete slab is required to know only its

**the mass of**a concrete slab whose volume is 15 m3.Solution: for finding the mass of the concrete slab is required to know only its

**density**. In order to learn this information, you need to use a table of densities of various substances.3

According to this table

**the density**of concrete is 2300 kg/m3. Then to find the**mass**of the concrete slab, you will need to perform simple algebraic action: m = 15*2300 = 34500 kg, or 34.5 tons. Answer: the mass of the concrete slab is 34.5 tons4

Mass measurement in the traditional way using one of the oldest instruments of mankind - with the help of weights. This is due to the comparison of body weight with the reference weight of cargo weights.

Note

Compute by the above formula, you must realize that in this way is known the rest mass of the body. An interesting fact that many elementary particles have an oscillating mass, which depends on the speed of their movement. If an elementary particle moving with the speed of the body, this particle is massless (e.g. photon). If the speed of motion of the particle below the speed of light, such a particle is called massive.

Useful advice

When measuring mass, we should never forget what the system will be given final result. There is a view that in the SI system, mass is measured in kilograms, while in the CGS system, mass is measured in grams. Also, mass is measured in tonnes, kilograms, carats, pounds, ounces, pecks, and in many different units depending on country and culture. In our country, for example, a lot of old measured in poods, berkovtsah, spools.

# Advice 3: How to find density chemistry

**Density**is one of the most important parameters of the physical body. According to the definition, density is a scalar value, which is measured for the homogeneous bodies as a ratio of body mass to its volume. There are several ways to learn the value of this parameter.

You will need

- - scales;
- - measuring Cup;
- - table volumes.

Instruction

1

Based on the definition, in order to know the density, you need to find the mass and volume of the body. This rule holds true for solids and liquids. Put the body on the scale and you will see the necessary quantitative indicators. Put the resulting value in pounds, which are the basic unit in the measurement system. If you know the mass of the liquid substance, before pouring it into the flask and weigh out the mass of the flask. You will need to take it away from the result.

2

If the body whose density you want to find is a regular geometric figure, you will be much easier. To find the volume of regular shapes, you can use the volumes table, find the formula and calculate the result. If the figure is wrong, take a measuring Cup and fill it with water (not completely). Write down what mark is water. Then lower the examined body in the water and mark the number where is the water now. The difference between second and first value will be the required volume. The liquid volume can also be measured using the same measuring Cup.

3

You only need to substitute the received data into the formula ρ = m/V where m is mass, and V is the volume of a material.

4

**The density of**gases is different. To do this you need to know the molar mass of the gas and its normal volume. If, according to the condition of the problem, the action takes place under normal conditions (temperature 0 C and pressure of 760 mm of mercury.St.), the normal volume is 22.4 l/mol. Molar mass is the mass of one mole of a substance. The formula for finding the density of gas is ρ = M/V norms.

5

If the temperature or pressure different from normal, to determine the density of the gas you have to use the formula of Clapeyron-Mendeleev and find the volume of gas: ρ* V = m/M * R*T, where ρ is the pressure, V the volume, m is the mass of gas, M – molar mass, T is the temperature in Kelvin and R is the universal gas constant, which is equal to 8.3 j/mol*K.

# Advice 4: How to find the density of milk

The density of milk is called a lot of milk at the temperature of 20oC, contained in a unit volume. The density of milk is considered an indicator of its naturalness. Its determination requires the use of special devices.

## The concept of density of milk

According to generally accepted standards, the density of milk is the density of such component parts as milk fat, lactose, proteins and salts. In fact, the density reflects the content in the milk of all these components. For density, you can determine whether milk is diluted with water or not.

In determining the milk density, it is recommended to check the equipment used. We are talking about echodensity that accuracy may be completely unsuitable for such measurements. To determine this characteristic is common to use milk glass hydrometers. By the way, this value should be determined not sooner than two hours after milking cows.

## How to determine the density of milk?

To determine the exact density of milk will be required to prepare a measuring cylinder of 250 ml with a diameter of 5 cm and echodensity. You should also find out if lastdelimiter tested in the laboratory of measures and measuring instruments. Be sure to read the results of this test. If the instrument is all right, you can start the density measurement.

Take milk, cooked to analyze, carefully along the wall, pour it into the cylinder to 2/3 volume. Make sure that during the pouring was not formed foam. Then take a dry echodensity and dip it in milk. The device must be in a free floating condition. About a couple of minute fluctuations echodensity must stop. This will mean that the time has come to measure the density and temperature of milk on the upper edge of the meniscus. The eyes should be level with the line of the meniscus.

Perform the measurement twice. Be sure to slightly push echodensity find the arithmetic mean of the two definitions. To determine the relative density of milk is highly recommended when the temperature of 20oC. If it was higher the density indications will need to add of 0.0002 for each degree. With decreasing temperature this value instead should be deducted. Incidentally, in the Guest there is even a special table amendments for test methods milk. It turns out that to determine the density of the milk will not require some specific knowledge. It is enough only to study in detail the sequence of actions.