The density of hydrogen gas at standard temperature and pressure (STP) is approximately 0.08988 g/L.
To understand this value, we first need to define what STP means. Standard conditions are defined as a temperature of 0 degrees Celsius (273.15 Kelvin) and a pressure of 1 atmosphere (101.325 kPa). Under these conditions, gases behave almost ideally, allowing us to use the ideal gas law to derive their properties.
Hydrogen (H2) is the lightest and most abundant element in the universe. When it exists as a gas, it has a very low density compared with other gases. This low density can be attributed to the small molecular weight of hydrogen, which is about 2 g/mol. The density can be calculated using the ideal gas equation, and when you plug in the values corresponding to STP, you find that hydrogen’s density is around 0.08988 g/L, making it significantly less dense than air, which has an average density of about 1.225 g/L at the same conditions.