The radius of the gas cylinder is \[ r = \frac{2.8}{2} = 1.4 \text{ decimeters} \] and the height is \[ h = 7.5 \text{ decimeters} \] Therefore, the volume of the gas cylinder is \[ \pi r^2 h = \frac{22}{7} \times (1.4)^2 \times 7.5 \text{ cubic decimeters} \] \[ = \frac{22 \times 14 \times 14 \times 75}{7 \times 10 \times 10 \times 10} = 46.2 \text{ cubic decimeters} \] So, the amount of gas in the cylinder is \[ 325 \times 46.2 = 15015 \text{ grams} = 15.015 \text{ kilograms} \quad \text{(Answer)} \]