Agas sample in a closed, expandable container of initial volume 5.00 l was allowed to warm from 25 °c to 35 ° c. what was its new volume, assuming the pressure and amount of gas do not change ?

Charles law states that volume of gas is directly proportional to temperature of gas at constant pressure and fixed amount of gas.
V / T = k
where V - volume , T - temperature in Kelvin and k - constant

where parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
T1 = 25 °C + 273 = 298 K
T2 = 35 °C + 273 = 308 K
substituting values in the equation,

V = 5.17 L
new volume is 5.17 L