The molecular mass of pyrene is 204.4 g/mol.
From;
ΔT = Kb m i
Where;
- ΔT = boiling point elevation
- Kb = boiling point constant
- m = molality
- i = Van't Hoff factor
Since the compound is molecular; i = 1
The number of moles of pyrene = 4.04 g/MM
Where; MM = molar mass of pyrene
molality = number of moles of pyrene/mass of solvent in Kg
The mass of solvent = 10 g or 0.01 Kg
molality = 4.04 g/MM/0.01
ΔT = Boiling point of solution - Boiling point of pure solvent
ΔT = 85.1°C - 80.1°C
ΔT = 5°C
5 = 2.53 × 4.04 g/MM/0.01 × 1
5 = 10.22 × 1/0.01 MM
0.05MM = 10.22
MM= 10.22/0.05
MM= 204.4 g/mol
Learn more: brainly.com/question/2292439
Calcium has a chemical symbol of Ca and has an atomic number of 20. This means that a neutral calcium ion will have 20 protons and 20 electrons. As part of Group 2 (alkaline earth metals), a calcium ion will be formed by ejecting 2 electrons from the neutral Ca atom. In chemical equation,
Ca --> Ca²⁺ + 2e⁻
Explanation:
When the water droplets are placed in oily surface, oil being non-polar, thus there will not be adhesive force between water and oil.
Thus, surface tension is the factor which is responsible for shape of the water droplets to be spherical. The water molecules are pulled into the spherical shape by the action of the cohesive forces which is acting on the surface layer. As, the medium is totally different outside, the water molecules tend to get the minimum area and thus, forming spherical droplets.
Answer:
NaCl= ionic bond.
H2O=covalent bond.
Explanation:
NaCl:
Happens between metal and non-metal. since metal needs to lose an electron to get a full outer shell of electrons, sodium (Na) loses one electron and has a full outer shell of electrons.
chlorine is a gas so it needs to gain electrons to have a full outer shell. since it is in group 7, it needs to gain 1 electron for a full outer shell of electrons.
the lost electron from sodium is given to chlorine. this creates ions (a charged particle) so it is Na+Cl-. this creates a strong electrostatic attraction between the elements and causes them to join together in a lattice form.
H2O:
Covalent bonds happens between 2 gases. they share an electron or 2, and the bonds are very strong.
since oxygen needs 2 molecules to form a full outer shell. hydrogen have 1 atom in outer shell so they share the electron with the oxygen atom.
I can't fully explain why this is for H2O, but I hope you understand it.
A, Homogenous | b, heterogenous | c, homogenous
