# Mass density and volume relationship to temperature

### Specific volume - Wikipedia d = mV. Example: A brick of salt measuring cm x cm x cm has a mass of g. What is its density? Step 1: Calculate the volume. Relationship between density, pressure, and What happens to density if temperature increases? – Decreases ρ ~ 1/T (mass per unit volume). • Pressure: P. Density is the mass of any material per unit volume. Remember that temperature is related to the average kinetic energy of the atoms or molecules within the.

The volume of a substance is determined by how much material is present and how closely the particles of the material are packed together. As a result, temperature and pressure can greatly affect the volume of a substance, especially gases. As with mass, increasing and decreasing the amount of material also increases and decreases the volume of the substance. For example, 10 grams of freshwater has a volume of 10 milliliters. Unlike mass and volume, increasing the amount of material measured does not increase or decrease density. This makes density a useful property in identifying many substances. However, since volume deviates with changes in temperature and pressure, density can also change with temperature and pressure.

Specific Gravity One derivative measurement of density is specific gravity. Specific gravity compares the density of a substance with the density of a reference material. In the case of gases, the reference material is standard dry air, or air without water. In the case of liquids and solids, the reference material is fresh water. Specific gravity is calculated by dividing the density of a substance by the reference substance's density.

For example, gold has a density of This yields a specific gravity of This means gold is Buoyancy Whether an object floats or sinks is determined by the downward force of gravity and an upward buoyant force.

### How are density mass and volume related? + Example

If the buoyant force is greater, an object floats. Within a particular phase, how does the density depend on temperature? Remember that temperature is related to the average kinetic energy of the atoms or molecules within the substance. Pure Water The density of liquid water is approximately 1. Let's look at the density of water at 25 deg C and compare that to a higher temperature, 80 deg C. The density decreases from 0. This makes sense because, as heat is added to the liquid water, there is greater kinetic energy of the molecules and there are also more vibrations of the water molecules.

Together these mean that each H2O unit in liquid water takes up more space as the temperature increases. We see the same trend in going from liquid water at 25 deg C 0. Density increase as the temperature decreases. Below 4 deg C, however, the density decreases again. How can we explain this? Remember that liquid water and solid water have the same network of bonds.

## How are density mass and volume related?

Liquid water at 25 deg is so rapidly breaking bonds between H2O units and reforming them that extra water molecules get trapped inside the water lattice. This is the reason why liquid water is more dense than solid water. The bonds in water break more slowly as temperature decreases and the structure tend to trap fewer extra water molecules.