Plz will give brainliest, 50 ! use your knowledge of the law of conversation of mass to answer the following question: from a laboratory process, a student collects 28.0g of hydrogen and 224.0g of oxygen. how much water was originally involved in the process?

According to law of conservation of mass, in a chemical reaction mass can neither be destroyed nor created thus, the total mass created here will be 224 g+28 g=252 g thus, mass of involved should be 252 g.

This can be experimentally proved as follows:

The balanced chemical reaction for the above process will be as follows:

Considering any one of the reactant.

2 mol of are produced from 2 mol of thus, 1 mol of produced from 1 mol of .

Now, mass of hydrogen gas is 28.0 g, molar mass is 2 g/mol, converting mass into number of moles:

thus, 14 mol of produced from 1×14=14 mol of .

Molar mass of is 18 g/mol. Converting number of moles into mass as follows:

m=n×M=14 mol×18 g/mol=252 g

Thus, mass of involved in the reaction will be 252 g.

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).