The temperature of a gas rose from 27°C to 77°C. At 77°C, the volume of the gas was 7.5 L. If the pressure did not change, what
was the initial volume of the gas

The initial volume of the gas : 6.43 L

Further explanation

Given

Temperature :

T₁=27+273 = 300 K

T₂=77+273 = 350 K

Volume : V₂=7.5 L

Required

The initial volume=V₁

Solution

Charles's Law  

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

Input the value :

V₁=(V₂ x T₁)/T₂

V₁=(7.5 L x 300 K)/350 K

V₁ = 6.43 L

Ithink that the use of creativity in the sciences entails that one produce something out of nothing or from another thing. with this, i think that the he wrote down his results as four parts of the atomic theory is the manifestation of the  creativity of john dalton.

"electrical energy" transforms to "thermal energy".hope my answer has you : )