Definition of melting point:
The melting point of solid is defined as the temperature at which the solid exists in equilibrium with its liquid under an external pressure of one atmosphere.
Reason:
The melting point is an important physical property of a compound.
1) The melting point can be used to identify a substance.
2) As an indication of its purity.
Is bubble chamber one of your choices? Bubble chamber sounds like a good fit for the question.
Answer:
C
Explanation:
You can see in the chemical equation that 7 
are used up to produce 6
The correct answer for the question that is being presented above is this one: "b. positive" Eugen Goldstein discovered in 1886 that atoms also have positive charges. He was a German physicist and an early investigator of discharge tubes. He also discovered the anode rays.
Answer:
A. Dipole-dipole forces; B. dipole-dipole forces;
C. ion-dipole forces; D. ion-dipole forces
Explanation:
A. HF
HF is a weak acid but a highly polar molecule. The strongest intermolecular force with water is an especially strong dipole-dipole force (hydrogen bonding) of the type
H-F· · ·H-OH and H₂O· · ·H-F
B. CH₃OH
CH₃OH has a highly polar O-H bond. The strongest intermolecular force with water is the especially strong dipole-dipole force (hydrogen bonding):
CH₃(H)O· · ·H-OH and CH₃O-H· · ·OH₂
C. CaCl₂
CaCl₂(s) ⟶Ca²⁺(aq) + 2Cl⁻(aq)
CaCl₂ separates into hydrated ions in solution. The strongest intermolecular force with water is ion-dipole attraction.
Ca²⁺· · ·OH₂ and Cl⁻· · ·H-OH
D. FeBr₃
FeBr₃(s) ⟶Fe³⁺(aq) + 3Br⁻(aq)
FeBr₃ separates into hydrated ions in solution. The strongest intermolecular force with water is ion-dipole attraction.
Fe³⁺· · ·OH₂ and Br⁻· · ·H-OH
