An example of a physical change
is liquid water turning into vapor. Physical change is that it may involve a
change in phase but does not involve a change in molecular structure.
C. MgCl2
This structure forms a ionic bond, which are generally stronger than covalent bonds. All of the other choices are covalent.
The vapor pressure of the two jars are the same.
The volume of water inside the container does not change the vapor pressure.
As long as the liquid remains being water and the temperature does not change the vapor pressure will be the same. The vapor pressure depends only in the nature of the substance and the temperature of the system.
If you want to know more about this, i.e. why, here you have additional explanation:
The vapor pressure is the pressure of the vapor of a substance in equilibrium with the substance in liquid (or solid state) and it is due to the fact that some molecules in the liquid (or solid), those that are close to the surface of liquid in contact with the gas phase and that have enough kinetic energy, evaporate.
At equilibrium the number of molecules passing from the liquid state to the gas state is equal to the number of molecules that pass from the gas state to the liquid state. If the volume of liquid is increased or decreased, as long as the temperaature of the system remains constant the equilibrium is reached again with the same vapor pressure.
Answer:
4 tert-butylcyclohexane will have the higher Rf value when ethyl acetate is used as the developing solvent because the 4-tert-butylcyclohexanol is the more polar compound that can form hydrogen bonds with the polar silica gel stationary phase.
this means less polar 4-tert-butylcyclohexanol will have a higher Rf
Answer:
The most important thing to know is that an α-particle (alpha particle) is a helium nucleus.
Explanation:
It contains 2 protons and 2 neutrons, for a mass number of 4.
During α-decay, an atomic nucleus emits an alpha particle. It transforms (or decays) into an atom with an atomic number 2 less and a mass number 4 less.
Thus, radium-226 decays through α-particle emission to form radon-222 according to the equation:
226
88
Ra
→
222
86
Rn
+
4
2
He
Note that the sum of the subscripts (atomic numbers or charges) is the same on each side of the equation. Also, the sum of the superscripts (masses) is the same on each side of the equation.
EXAMPLE
Write a balanced nuclear equation for the α decay of polonium-208.
Solution
The unbalanced equation is
208
84
Po
→
4
2
He
+
X
The superscript of
X
must be 208 – 4 = 204.
The subscript of
X
must be 84 – 2 = 82.
Element 82 is Pb. So the equation is
208
84
Po
→
4
2
He
+
204
82
Pb
Explanation:hope this is right and helps