The first one.........................
Using ideal gas equation,

Here,
P denotes pressure
V denotes volume
n denotes number of moles of gas
R denotes gas constant
T denotes temperature
The values at STP will be:
P=1 atm
T=25 C+273 K =298.15K
V=663 ml=0.663L
R=0.0821 atm L mol ⁻¹
Mass of gas given=1.25 g g
Molar mass of gas given=?


Putting all the values in the above equation,

Molar mass of the gas=46.15
C, because a homogeneous mixture is evenly mixed.
All those others would be heterogeneous (not evenly mixed).
Order.
Hope this helps! :)
440 hertz = 440/seconds
1/440 seconds = period of the sound wave.
so Answer is 2.2727272* 10^-3 second or 1/440 seconds