What observations and reasoning led to the development of Hubble's Law?

Hubble's law says that the universe is expanding outward.

Explanation:

Actually Hubble's law was discovered before the Big Bang theory was formulated. The Big Bang Theory is an attempt to explain the observations that led to Hubble's Law.Before the 1900s the theory was that the universe was eternal and self existent. The idea was that the universe was in a steady state having always existed and would always continue to exist. Albert Einstein even changed the equations in his general theory of relativity to reflect the idea of a steady state. Later he called putting in a fudge factor to result in a steady state the worse mistake of his life.

Hubble observed that most of the universe has a red shift indicating that the universe is expanding and moving away from itself. The further out that the universe is observed the faster it is moving apart.

These observations were inconsistent with a steady state universe.

The Big Bang theory extrapolated backwards. If the universe is expanding and spreading out from itself then further back in time the universe was closer together. The Theory explained Hubble's observations by the idea that at the beginning of time ( for our universe) all the matter and energy were together in one place.

This super dense ball of matter and energy then exploded outwards creating space and time as it is presently observed. The question was would the forces of gravity and black holes bring the matter and energy back together again. The answer found in 1998 was no. The rate of the expansion of the universe is increasing not slowing down and the universe will not collapse back into the super dense ball of matter that it began as.

The Big Bang Theory postulated based on the empirical evidence that our universe had a beginning and it will eventually cease to exist. The conclusion based on Hubble's observations is that matter and energy are not eternal and self existent.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.