Answer: 12.0 milliliters of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn.
Explanation:
moles =
moles of zinc =
The balanced chemical equation is :
According to stoichiometry:
1 mole of zinc reacts with = 2 moles of HCl
Thus 0.0390 moles of zinc reacts with = 
moles of HCl
To calculate the volume for given molarity, we use the equation:
.....(1)
Molarity of 
solution = 6.50 M
Volume of solution = ?
Putting values in equation 1, we get:
Thus 12.0 ml of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn
Answer : The vapor pressure of propane at 
is 17.73 atm.
Explanation :
The Clausius- Clapeyron equation is :
where,
= vapor pressure of propane at = ?
= vapor pressure of propane at normal boiling point = 1 atm
= temperature of propane = 
= normal boiling point of propane = 
= heat of vaporization = 24.54 kJ/mole = 24540 J/mole
R = universal constant = 8.314 J/K.mole
Now put all the given values in the above formula, we get:
Hence, the vapor pressure of propane at is 17.73 atm.
For the hypothesis put what you think will happen
You can simply subtract the atomic number from the mass number in order to find the number of neutrons.
