# Volume of gas produced in a reaction

Is it correct to say that 'x' litres of a gas were produced in a reaction, calculating x using the ideal gas equation, since the volume occupied by a gas is taken to be the volume of the container it is in?

• They usually say "$x$ liters of a gas was produced at STP". At STP, the temperature and pressure are fixed, so the volume depends on the amount of gas produced. – Pritt Balagopal Jun 17 '17 at 2:42
• But isn't the volume taken to be the volume of the container, which is constant throughout? – User Jun 17 '17 at 3:46
• Not if you keep a fixed pressure. Think of pistons that exert constant pressure. More gas means the piston expands more. – Pritt Balagopal Jun 17 '17 at 6:50