Answer:
a.) It is a chemical reaction because a new substance was formed and a colour change occurred in the reaction.
b.) Iron- Metallic element
sulpher- Non-Metalic element
Iron Sulphide- Compound
HOPE IT HELPS....
Answer:
New volume is 25.0 mL
Explanation:
Let's assume the gas sample behaves ideally.
According to combined gas law for an ideal gas-

where,
and
represent initial and final pressure respectively
and
represent initial and final volume respectively
and
represent initial and final temperature (in kelvin) respectively
Here,
,
,
and 
So, 
So, the new volume is 25.0 mL
Answer:
Silicon is the basic material used to make computer chips, transistors, silicon diodes and other electronic circuits and switching devices because its atomic structure makes the element an ideal semiconductor.
Answer: oil spill, forest fire
Explanation:
The short term environmental change is a change that occur in an environment which exerts it's effect over the environment and the living beings for a short duration. The damage caused by the short term environmental change can be recovered in a short time. The oil spill and forests fire are the example of short term environmental changes.
The oil spill will reduce the abundance of the aquatic species until the oil is circulated out at the bay of the water body therefore, it is a short term environmental change.
Forests fire will remain ignited for a short period but can be destructive enough to cause damage to flora and fauna species. As time passes the reduced populations of flora and fauna can be recovered again.
1. Humidity
2. Temperature
3. Rainfall
In general, the electron pairs in a molecule that will adopt a shape to maximize their distance far apart, even charges repel each other as well as unlike charges attract,
for example H2O has two lone electrons pairs but it adopts an angular shape. Hope this help!!