Answer:
-0.93 °C; 100.26 °C
Step-by-step explanation:
(a) Freezing point depression
The formula for the freezing point depression ΔT_f is
ΔT_f = iKf·b
i is the van’t Hoff factor: the number of moles of particles you get from a solute.
For sucrose,
Sucrose (s) ⟶ sucrose (aq)
1 mole sucrose ⟶ 1 mol particles i = 1
ΔT_f = 1 × 1.86 × 0.50
ΔT_f = 0.93 °C
T_f = T_f° - ΔT_f
T_f = 0.00 – 0.93
T_f = -0.93 °C
(b) Boiling point elevation
The formula for the boiling point elevation ΔTb is
ΔTb = iKb·b
ΔTb = 1 × 0.512 × 0.50
ΔTb = 0.256 °C
Tb = Tb° + ΔTb
Tb = 100.00 + 0.256
Tb = 100.26 °C
Answer:
2+
Explanation:
Nickel has an atomic number of 28 meaning that it contains 28 protons in its nucleus. It would need 28 electrons in order to have no charge, because the positive and negative charges balance each other out. Since this atom of Ni has 26 electrons, it has lost 2 of its electrons, and therefore has a positive charge of 2.
Silicon is the second most abundant element in the Earth´s crust and makes up around 27% of it.
