Explanation:
Sublimation describes a solid turning directly into a gas. Melting, on the other hand, occurs when a solid turns into a liquid. Water can, under the right circumstances, sublimate, though it usually melts at temperatures above 0 degrees Celsius or 32 degrees Fahrenheit. Carbon dioxide (CO2), however, is very different. The conditions that determine whether CO2 melts or sublimates are both temperature and atmospheric pressure.
Answer: Bromine is Actually a Halogen!
Explanation: Bromine is in the 7th column of the Periodic Table. It needs that magic 8 valence electrons and it has 7.
Hoped that helped!
Statement D is the correct option as the solution will have pH of 3. It has an H3O+ ion concentration of 1 × 
mol/L and is acidic.
Explanation:
It is given in question that solution must have pH of 3. The value if being less than 7 shows that solution is acidic. The pH value of 3 indicates that given solution is highly acidic and has strong acid. Strong acid gets fully dissociated into 
ions.
pH of the solution is calculated as:
pH = -log10[]
the concentration or molarity of the hydronium ion is given as moles/litre
concentration of hydronium ion in the solution is 1 X moles/litre
putting the values in the equation:
pH = - log10( 1 X )
pH = 3 (acidic)
Thus it can be concluded that D option is the right answer.
Answer:
the heat rate required to cool down the gas from 535°C until 215°C is -2.5 kW.
Explanation:
assuming ideal gas behaviour:
PV=nRT
therefore
P= 109 Kpa= 1.07575 atm
V= 67 m3/hr = 18.6111 L/s
T= 215 °C = 488 K
R = 0.082 atm L /mol K
n = PV/RT = 109 Kpa = 1.07575 atm * 18.611 L/s /(0.082 atm L/mol K * 488 K)
n= 0.5 mol/s
since the changes in kinetic and potencial energy are negligible, the heat required is equal to the enthalpy change of the gas:
Q= n* Δh = 0.5 mol/s * (- 5 kJ/mol) =2.5 kW
