Specific Gravity: Definition, Formula, Use and The Difference With Density

Specific Gravity: Definition, Formula, Use and Difference with Density – What is meant by Specific Gravity and What is the Unit Formula? On this occasion About the knowledge.co.id will discuss it and of course the things that also cover it. Let's look at the discussion in the article below to understand it better.

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Specific Gravity: Definition, Formula, Use and The Difference With Density

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Specific gravity is the relative ratio between the density of a substance and the density of pure water. The specific gravity of a substance is the ratio of the substance's weight to its volume. The international system unit for specific gravity is N/m3.

Specific gravity is called rho and the formula for specific gravity is mass / volume, so the factors that affect specific gravity are the object's mass (m) and volume (V)p (rho) = m/

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Specific Gravity Formula

Specific gravity has a formula

m.g/v or w/v in units of n/m^3

with
m is mass,
g is gravity
v is the volume
w is the weight (weight).

Actually what is meant by the specific gravity of an object is the ratio of the density of the object to the density of water.

So that it can be interpreted, that specific gravity is the relative density of a material. Therefore, specific gravity has no units.

Specific gravity is a measurement of the mass per unit volume of an object. The higher the density of an object, the greater the mass of each volume.

The average density of each object is the total mass divided by the total volume.

An object with a higher density (eg iron) will have a lower volume than an object with the same mass that has a lower density (eg water).

The SI unit of density is kilograms per cubic meter (kg/m ). Density is used to define matter.

Each substance has a different density. And a substance regardless of mass, regardless of volume will have the same density. With the formula:

Note:
p or d is the weight of the type
m is the mass
V is volume
The unit of density in “CGS (centi-gram-second)” is: salt per cubic centimeter ( )
1 g/cm = 1000 kg/m

The specific gravity of pure water is 1g/cm or equal to 1000 kg/m specific gravity is a kind of characteristic, which used in testing the identity and purity of drug substances and excipients, especially the properties of liquids and other substances night type. Determination of specific gravity is done by pycnometer, aerometer, hydrostatic balance (Mohr-Westphal scale) and manometric method.

Density is a temperature-dependent material constant for solid, liquid, and homogeneous bodies of gas. Defined as the relationship of the mass (m) of a material to the volume (v).

Unless otherwise stated in the individual monograph, the designation of specific gravity is used only for liquids, and except stated otherwise, based on the ratio of the weight of the substance in the air at a temperature of 250 to the weight of water with the same volume and temperature The same.

If the temperature is specified in the monograph, specific gravity is the ratio of the weight of the substance in air at the specified temperature to the weight of water of the same volume and temperature. If at 250C the substance is solid, determine the specific gravity at the temperature indicated in the individual monograph, and refers to water which remains at 250C.

As explained in the previous chapter, the determination of specific gravity is usually carried out for liquid substances or compounds. For this reason, before explaining further about specific gravity, it is better for us to get to know the properties of the liquid. The properties of liquids, among others:

1. The shape follows the place and the volume is fixed.
2. The molecules can move but not as easily as the gas molecules move.
3. The particles are closer together than gases, so it is more difficult to compress.
4. Can be evaporated with the need for energy.

The specific gravity number or commonly referred to as density is the ratio between the specific gravity of a substance and the specific gravity of water. From this definition it can be concluded that density is a measure that has no units. It can be said that the density is n times the density of water, which means that the substance has n times the density of water.

d = ∫ ρ substance / ρ water = g/ml / g/ml

Density indicates the amount of mass per unit volume, with the approval of the CGS system. The density measure usually shows the number of grams per cubic centimeter at 20oC. In the pharmacopoeia, density is the specific gravity which refers to the size of the weight and is a comparison weight and equal volume parts of the substance under study relative to water, both of which are measured at temperature 20oC.

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Use of Specific Gravity

Specific gravity can be used in various ways to determine a substance, including:
• Determine the purity of a substance
• Get to know the state of the substance
• Indicates the sensitivity of the solution
Apart from being a number that is easy to remember and easy to use for calculating, the specific gravity of water is used as a comparison for the 2nd formula for calculating specific gravity, or what is called "Relative Specific Gravity".

The formula for relative specific gravity = mass of material / mass of water with the same volume.

In some cases, density is expressed as specific gravity or relative density. Generally used to express the density of some substances, such as water and air. Liquids have unique properties different from other types of substances.

Below is a basic explanation of Archimedes' law in physics lessons.

Archimedes' Law

An object that is immersed or partially or completely immersed in a liquid will experience an upward force equal to the liquid pushed by the object that was immersed or inserted earlier. Water is one of the liquid substances.

Some solid objects, when put in water will experience different events, including:

1. Sink
An object is said to sink if it sinks to the bottom of the water because the specific gravity of the object is greater than the specific gravity of the water. For example: stone, iron and soil
2. floating
An object is said to float if it is above the surface of the water because the specific gravity of the object is less than the specific gravity of the water. For example: cork, bottle caps, wood and ships.
3. Flying
An object is said to float if it is between the surface and the bottom of the water because the specific gravity of the object is equal to the specific gravity of the water. Examples are submarines, divers and chicken eggs floating in salt water.

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Difference between Density and Specific Gravity

The density of a substance is the ratio between the mass and volume of the substance. While specific gravity is the ratio between the weight and volume of an object.

Definition of Density

"Density is a measurement of mass for each unit volume of matter"

The higher the density of an object, the greater the mass of each volume. The average density of each object is the total mass divided by the total volume. An object that has a higher density (eg iron) will have a lower volume than an object of the same mass that has a lower density (eg water).

Density Unit

The SI unit of density is Kg/m3, Kg m−3

Density has the function of determining the substance. Each substance has a different density. And one substance regardless of mass and regardless of volume will have the same density.

Density formula

The formula for determining density is:

ρ = m/V

Formula Description:

ρ = density,
m = mass,
V = volume.

The unit of density in ‘CGS [centi-gram-second]’ is: g/cm3 (grams per cubic centimeter)

1 g/cm3 equals 1000 kg/m3

The density of pure water is 1 g/cm3 or = 1000 kg/m3 Apart from the numbers that are easy to remember and easy to use for calculate, then the density of water is used in comparison to the 2nd formula to calculate the density, or what is commonly called 'Mass Relative Type'

The differences in mass and specific gravity are:

Density

– Density is a scalar quantity (only has a Value)
– a measure of the inertia of an object. The greater the mass of the object, the greater the inertia.
– The size of the mass everywhere will remain the same.

Specific gravity

– Included as a Vector quantity (has both magnitude and direction)
– A measure of the magnitude of the gravitational force of the earth on an object.
– The magnitude depends on the magnitude of the gravitational acceleration where the object exists.

Density (mass density) is defined as the value of the mass density of an object which can be calculated by means of the mass of the substance per unit volume of the object itself.

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Problems example

1. Find the density of a cube whose side length is 5 cm if it is known that the mass of the cube is 250 grams

Is known :
m = 250 grams
s = 5 cm
Vcubus: s x s xs: 5 x 5x 5 = 125 cm3
asked :
ρ.... ?

answer :
ρ = m/v
ρ: 250 grams / 125 cm3: 2 grams/cm3
Then the density of the cube is 2 gram/cm3.

2. What is the mass of the block if the density of the block is 1000 kg/m3 and the volume of the block is 2 m3

Is known :
ρ = 1000 kg/m3
v = 2 m3
asked:
m... . ?

answer :
ρ = m/v
1000 kg/m3: m / 2 m3
m = 1000 kg/m3 x 2 m3
m = 2000 kg
So, the mass of the block is 2000 kg.

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