Chemical Engineering - Chemical Engineering Basics - Discussion

I think it's because of low density of air. So density change is negligible.

Density of air increases with temperature in gas and it decreases with temperature in liquid.

So why the answer is A?

When temperature increases the density of air decreases. This explains why candle flames look like it's going up due to free convection as result of the cold air around it having been heated up, its density reduces and so the lighter air current flows upwards leaving the denser, less heated air below, if not for the free convection due to heat transfer the flame will look spherical. So the answer is A.

Density of air decreases as the air temperature is increasing.

Density if air decrease with temperature increase.

Density =inversely proportional to temperature.

By ideal gas law Pv =nrt.

Density=pm avg/rt.

Air density will decrease by about 1% for a decrease of 10 hPa in pressure or 3 °C increases in temperature.