Answer: The correct option is 3.
Explanation: We are given a compound which is made up of iron and oxygen only. The ratio of the two are given as:

This means that, number of iron ions are 2
Number of oxide ions are 3
From the above information, the formula becomes : 
The valency of iron = 3
Valency of oxide = 2
This compound is named as iron (III) oxide.
Hence, the correct option is 3
To make everything easier to convert so everything universal
Answer:
0.64 kW
Explanation:
The potential energy of a mass (M) at some height (h) is computed from ...
PE = Mgh
At 1 kg/liter, the available power is the rate at which that energy is available ...
(490 kg/min)×(1 min/(60 s))×(9.8 m/s²)(8 m) ≈ 640.3 kg·m²/s³
= 640.3 W
In kilowatts, that is 0.64 kW.
Answer:
the answer is FALSE it is less than 60% not more
Answer:
Is 30
Explanation:
You have to minus de 56 with the 26