16 which change results in the formation of different substances? (1) burning of propane
(2) melting of nacl (s)
(3) deposition of co2(g)
(4) solidification of water

The correct answer is option (1).

Explanation:

Burning of propane in the presence of oxygen will form carbon-dioxide, water and heat.The chemical reaction can represented as in chemical equation:

This is an example of chemical change where new product is formed.

Where as in melting of sold sodium chloride, deposition of carbon-dioxide gas and solidification of water ;phase of the substance is changing that is a physical change is taking place.

Hence, the correct option is (1).

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).