Gay-Lussac's law gives the relationship between pressure of gas and temperature. It states for a fixed amount of gas, the pressure of gas is directly proportional to temperature at constant volume.
P / T = k
where P - pressure, T - temperature in Kelvin and k - constant
[tex] \frac{P1}{T1} = \frac{P2}{T2} [/tex]
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 - temperature in Kelvin - 20 °C + 273 = 293 K
substituting the values in the equation
[tex] \frac{1.8 atm}{293 K} = \frac{1.9 atm}{T} [/tex]
T = 309 K
new temperature in celcius scale - 309 K - 273 = 36 °C
