Water is made of two hydrogen atoms and one oxygen atom bonded together. julia is describing how water undergoes a physical change when it boils. she says that the particles shift to be farther apart and that the oxygen and hydrogen separate. she also says that the total mass of the steam is the same as the initial water, and that heat energy was required to cause the change. she finishes her description by saying that the steam can be turned back into water if it is cooled.

which is the mistake in her description?

1 .the total mass remains the same in physical changes.
2.the arrangement of particles may change in physical changes.
3.atoms remain bonded to each other in physical changes.
4.energy changes may occur in physical changes.

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).