Answer:
3.59x10^21 molecules
Explanation:
1mole of a substance contains 6.02x10^23 molecules.
Therefore, 1mole of C8H18 will also contain 6.02x10^23 molecules
1mole of C8H18 = (12x8) +(18x1) = 96 + 18 = 114g.
1mole (i.e 114g) oh C8H18 contains 6.02x10^23 molecules.
Therefore, 0.68g of C8H18 will contain = (0.68 x 6.02x10^23)/114 = 3.59x10^21 molecules
We will use boiling point formula:
ΔT = i Kb m
when ΔT is the temperature change from the pure solvent's boiling point to the boiling point of the solution = 77.85 °C - 76.5 °C = 1.35
and Kb is the boiling point constant =5.03
and m = molality
i = vant's Hoff factor
so by substitution, we can get the molality:
1.35 = 1 * 5.03 * m
∴ m = 0.27
when molality = moles / mass Kg
0.27 = moles / 0.015Kg
∴ moles = 0.00405 moles
∴ The molar mass = mass / moles
= 2 g / 0.00405 moles
= 493.8 g /mol
Answer:
1. negative
2. positive
3. neutral
Explanation:
Ok so it looks like they are asking for the charge (positive, negative, or neutral) of each thing
So for 1, it would be negative, because it's pointing to an electron. Electrons always have a negative charge.
So for 2, it would be positive, because it's pointing to a proton. Protons always have a positive charge
So for 3, it would be neutral, because it's pointing to a neutron. Neutrons always have a neutral charge.
Answer:
A
Explanation:
Flammability is a chemical property. The paper crumbling would be a physical property. The inability to attract a magnet or conduct electricity would be considered electrical properties
