Key Points
For many solids dissolved in liquid water, the solubility increases with temperature.
The increase in kinetic energy that comes with higher temperatures allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions.
Radioactive decay => C = Co { e ^ (- kt) |
Data:
Co = 2.00 mg
C = 0.25 mg
t = 4 hr 39 min
Time conversion: 4 hr 39 min = 4.65 hr
1) Replace the data in the equation to find k
C = Co { e ^ (-kt) } => C / Co = e ^ (-kt) => -kt = ln { C / Co} => kt = ln {Co / C}
=> k = ln {Co / C} / t = ln {2.00mg / 0.25mg} / 4.65 hr = 0.44719
2) Use C / Co = 1/2 to find the hallf-life
C / Co = e ^ (-kt) => -kt = ln (C / Co)
=> -kt = ln (1/2) => kt = ln(2) => t = ln (2) / k
t = ln(2) / 0.44719 = 1.55 hr.
Answer: 1.55 hr
Answer:
W and Z
Explanation:
Atoms of the SAME element OR two atoms of DIFFERENT elements will form a MOLECULE.
E.g. 2 atoms of hydrogen + 1 atom of oxygen => 1 molecule of water. This 1 molecule of water can also be called a compound.
Also, 2 atoms of Oxygen can combine to form 1 molecule of Oxygen. This 1 molecule of Oxygen cannot be referred to as a compound.
Atoms of DIFFERENT elements form a COMPOUND.
Therefore, compounds are molecules, but molecules are not compounds.
Thus, the combination of atoms that will form a molecule, but not a compound is:
W(oxygen) + Z(oxygen) = molecule
Well If The Forces Were Balanced It Would Not Move So True