When two substances react to form a new material with different properties, a Chemical change has occurred.
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
When the positive ions and negative ions react, they become neutral
Answer:
protons = atomic numbermass number = protons + neutronsatomic number = mass number - neutrons = 78-38 = 40
Explanation:
They move because of convection currents in the mantle
