This is called a combustion reaction. A combustion reaction involves oxygen gas. Most combustion reaction are exothermic as they give off heat. When organic molecules (containing carbon and hydrogen) combust the reaction products are carbon dioxide and water as well as heat or light. Combustion reactions may be complete or incomplete, a complete combustion releases more energy than incomplete combustion.
Answer:
Plants
Explanation:
Plants, part of the biosphere, grow in the soil, which is part of the geosphere
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D. Not all mixtures are heterogeneous
Seismic waves is the energy of and earthquake aka Elastic Energy
The number of grams of radon 222 did it have 15.2 ago was 49.6 grams( answer C)
<u>calculation</u>
- calculate the number of half life it has covered from 15.2 days to 3.8 days
that is divide 15.2/ 3.8 = 4 half life
- half life is time taken for a radio activity of a specified isotope to fall to half its original mass
therefore 3.8 days ago it was 3.1 x2 = 6.2 grams
7.6 days ago it was 6.2 x2 = 12.4 grams
11.4 days ago it was 12.4 x2= 24.8 grams
15.2 days ago it was 24.8 x2=49.6 grams