If, after turning on the electric heater, the air temperature in the room increased from 17C to 27C

If, after turning on the electric heater, the air temperature in the room increased from 17C to 27C at a constant pressure, then the number of molecules in the room …

According to the Clapeyron-Mendeleev equation
P * V = n * R * T,
Where
P – gas pressure,
V is its volume,
n is the amount of gas,
R – gas constant,
T is the absolute temperature in K.
Since the volume and pressure of the gas do not change, you can write:
n1 * T1 = n2 * T2,
T1 = t1 + 273 ° = 17 ° C + 273 ° = 290 ° K,
T2 = t2 + 273 ° = 27 ° C + 273 ° = 300 ° K;
From here we get:
n2 / n1 = T1 / T2 = 290/300 = 0.967;
The number of molecules in the room has decreased by
(n1 – n2) * 100% / n1 = 100% * (1 – n2 / n1) = 3.3%.
Response decreased by 3.3%