The answer would be , a Chemical change!
Answer:
<em>Hydrogen.</em>
Explanation:
You've probably seen "
" which is the formula for water. It means that there's 2 hydrogen atoms, and one oxygen atom, in one molecule of water.
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Answer:
It is classified as a pure substance
Explanation:
Oxygen is a gas present in the atmosphere in the pure elemental form.
Get to know first how many moles in the gas:n = pV/RT= (1.013*10^5*750/760) Pa *1.49*10^-3 m^3/(8.314 J/(molK)*298) n = 0.0601 moles.
The combustion energies are 889 kJ/mol (methane) and 2 220 kJ (propane) x = moles methane, y = moles propane
x*889 + y*2220 = 778 x + y = 0.0601----------- x = 0.267784 moles = 0.267784*100/0.0601 = 44.6 % y = 0.243216 moles = 0.243216*100/0.0601 = 55.4 %
The valence of helium is 0.
