Converting the temperature, 295 K from Kelvin to Celsius scale:
Water has a boiling point of 
and a melting point of 
When we compare water at two different temperatures, 
we can say that water is in liquid form at both these temperatures as both of them are quite below the boiling temperature and above the melting temperature.
The temperature difference between water at the given two temperatures = 
Water at 
is at a higher temperature and so is warmer than water at a lower temperature of 
.
The answer should be; 11
The atomic mass number is found by combining the number of protons and neutrons
Hope this helps :)
1. Change in temperature
2. Odour being produced
3. Gas bubbles being formed
4. Solid precipitate is formed
5. Permanent change in colour
6. Light is being produced
From ideal gas equation that is PV=nRT
n(number of moles)=PV/RT
P=760 torr
V=4.50L
R(gas constant =62.363667torr/l/mol
T=273 +273=298k
n is therefore (760torr x4.50L) /62.36367 torr/L/mol x298k =0.184moles
the molar mass of NO2 is 46 therefore density= 0.184 x 46=8.464g/l
