1. Which one is heavier : 1000 Ton Steel or 1000 Ton Cotton ?
I would like to answer question 1. Because all given answers were wrong.
Heaviness or (weight) in physics is a Vector. The given "1000 ton" is mass which is scalar. If you want to decide which one is heavier then you need to convert these scalar values into vectors. To do so you need to multiply this scalar value with the vector of gravity Which is different on every spot of the Earth.
Let's say you're measuring the weight on the same spot. But there'll be gravitational difference because of "density" of those materials.
Steel's density is 7.85 g/cm
3 and Cotton's density is 1.55 g/cm
3. That means 10 tons of steel will be 4 times smaller than 10 tons of cotton.
When you measure Weight of the Steel and cotton on the same spot of the Earth; Steel will be heavier than cotton. Because Cotton's center of gravity is further than Earth's core. The difference might be small but they're not same.
Trust me I'm an engineer.
Weight:
https://en.wikipedia.org/wiki/WeightGravity of Earth:
https://en.wikipedia.org/wiki/Gravity_of_EarthDensity of steel:
http://hypertextbook.com/facts/2004/KarenSutherland.shtmlDensity of Cotton:
https://en.wikipedia.org/wiki/Cotton#Fiber_propertiesedit:
Also 4th question's answers are also wrong/missing. Since you didn't give the amounts of the Hydrogen and Oxygen.
a. wrong; because there're only 1 H and 1 O, that means you have Hydroxide (HO
- anion.
https://en.wikipedia.org/wiki/Hydroxideb. missing; there're more chemical substances such as Hydrogen peroxide:
https://en.wikipedia.org/wiki/Hydrogen_peroxide
still waiting for this awesome giveway.
and have fun 
