Answer: 
Explanation:
The Chemical equation for the formation of rust is:
Iron + Water + Oxygen ----> Rust
4 Fe(s) + 6 H2O(l) + 3 O2(g) → 4 Fe(OH)3(s)
The Iron Hydroxide However dehydrates to produce Fe2O3 * nH2O
Answer:
D. chemical alters the atomic structure of a substance, while physical does not
hope this helps!
Answer: 4.56 Joules
Explanation:-
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

Q = Heat absorbed = ?
m= mass of substance = 2.5 g
c = specific heat capacity = 
Initial temperature =
= 25.0°C
Final temperature =
= 29.9°C
Change in temperature ,
Putting in the values, we get:


The heat absorbed by gallium must be 4.56 Joules
The test for this is fairly simple.
We take a glowing match or splint near the gas sample, if the glow intensifies, oxygen is present.
If a lit splint or match goes out with a popping sound, this means that hydrogen is present.
Explanation:
Conduction is a form of heat transfer between one body and another. It usually occurs when a warmer object is in contact with a cooler one. Heat generally flows from a region of high temperature to a place at a lower temperature.
- Conduction is very pronounced in solid bodies.
- The heat transfer causes a net transfer of the average kinetic energy of one body to the other.
- Some examples are: heating of iron by a hotter metallic body, the pot hand getting hotter as cooking continues, cooling of ice by touching it.