Some types of liquids found at room temperature are water-based aqueous solutions, certain oils such as vegetable oil, fuel sources such as gasoline, alcohols, juices and biological fluids such as blood and urine. Some elements, such as mercury and bromine, are naturally found as liquids.
Liquids are one of the three basic states of matter. Any substance that has a definite volume but no definite shape is a liquid. Because the state of matter of a given substance can change with conditions such as increasing or decreasing temperature, substances that are not typically found as a liquid at room temperature can become liquid under the right conditions. Liquefying processes are used in industry and laboratory settings, and include the melting of metals such as iron and nickel to fill molds during manufacturing processes and the cooling of gases such as nitrogen to make liquid nitrogen for chemical freezing processes.
Aqueous solutions are common liquids in laboratory and biological settings. In an aqueous solution, water acts as a solvent and dissociates certain ionic and molecular compounds. If a solid substance fully dissociates in water, the solution will appear to be a uniform liquid and there will no be trace of the added substance in solid form until the water is removed from the system.