The correct answer is 1 and 4.
Burning of fossil fuels releases harmful gases to the atmosphere which leads to climate change. Burning of hydrogen gas releases water which has no negative effect on climate.
Burning of both fossil fuels and hydrogen takes place inside expensive fuel cells.
Fossil fuels are widely available and easy to locate whereas hydrogen is available in the combined form with other elements. Hydrogen are not found in pure form on earth.
Fossil fuels are non-renewable source of energy which means they cannot be replaced in short time.
People who have been struck by lightning do not carry an electrical charge and can be touched is True.
heat lightning is lightning flashes in the sky that do not have the accompanying sound of thunder so false just like the others
Li2O
Lithium is a metal with an oxidation number of 1+ and oxygen is a nonmetal with an oxidation number of 2-. Which chemical formula represents the compound formed by these two elements? Li2O is the correct answer because lithium has one valence electron and oxygen has six.
Hope this helped.
Use conservation of momentum ;
m1u1 + m2u2 = m1v1 + m2v2
1200×15.6 + 0 = 2700v
v = 18720/2700
v = 6.933 or ~ 7 m/s
