The amount of gas wasted when you turn on a stove and then don't use it depends on the type of stove and how long it remains on without being used. Let's consider a gas stove with a pilot light or an electric ignition system.
Pilot Light: Some older gas stoves have a continuously burning pilot light, which ignites the gas burner when you turn the stove on. If you turn on the stove and then don't use it for an extended period, the pilot light continues to consume a small amount of gas as long as it remains lit.
Electric Ignition: Most modern gas stoves use an electric ignition system. When you turn on the stove, an electric spark ignites the gas burner. If you turn on the stove but don't actually light the burner, there is no continuous gas flow, and therefore, no gas is being wasted.
In both cases, the amount of gas wasted is relatively small compared to the gas consumption when the burner is actively in use. The pilot light consumes only a tiny fraction of the gas used by a fully operating burner, and the momentary flow of gas when turning on the stove without lighting the burner is also minimal.
While the wasted gas may not be significant for short periods, it's still a good practice to turn off the stove if you're not using it to save energy and reduce the risk of accidents. Additionally, if you have an older stove with a pilot light, consider upgrading to a more energy-efficient model that doesn't use a continuously burning flame.