Answer:
0.06819 atm or 51.8559 torr
Explanation:
To solve this problem we will use the following equation:
ln(P1/P2) = H (vap) / R (1/T2- 1/T1)
Given data:
P1= 760 torr
P2= ?
T1= 78.4 °C+273 = 351.4 K
T2= 19°C + 273 = 292 k
heat of vaporization = 38.56kJ/mol
Now we will put the values in equation:
ln (760 torr/ P2) = 38.56 × 1000 j/ 8.314 j k-1 (1/ 292 - 1/ 351.4)
ln (760 torr/ P2) = 2.6849
760 torr/ P2 = 14.656
P2 = 51.8559 torr
or
P2= 51.8559 torr × 0.001315 atm
P2 = 0.06819 atm
This is a trick question really, or at least the wording is poor chemistry. Molecules are the smallest unit of a simple covalent compound that retain the chemical properties of that compound. Covalent means there are bonds between atoms due to sharing a pair of electrons, and an example of such a compound is water, H2O. There are discrete H2O molecules moving past each other, with only weak intermolecular forces in between them.
Yet MgCl2 is not a covalent compound. In fact the bonding is ionic, meaning that electrons are transferred between the atoms to form positive and negative ions, which then electrostatically attract. Ionic compounds form a giant ionic lattice, a continuous structure of millions of these ions. An ionic molecule does not really exist.
What I assume is meant is the formula unit, a term very similar in meaning to a molecule. The difference is well shown by comparing empirical formula and molecular formula. A molecular formula shows how many of each atom are in a molecule, yet the empirical formula just shows the simplest whole-number ratio between the number of these atoms. Take ethane: the molecular formula is C2H6 and the empirical formula is CH3.
The ionic formula unit is like this empirical formula. By this standard the likely answer is A (1), because the formula shows that for every magnesium atom, there are two chlorine atoms.
I hope this helps :)
There is no movement
The speed is not correct
There is a drift or a creep
The force is incorrect