The percentage by mass of oxygen in the compound
find the total mass=( 1.900+ 0250 +0.850) = 3
the percentage mass mass of oxgyen/total mass x100
that is (0.850/3) x100=28.33%
Answer: decomposition
Explanation:
1 . Combustion is a type of chemical reaction in which a hydrocarbon reacts with oxygen to form carbon dioxide ans water along with liberation of large amount of energy.
2. Decomposition is a type of chemical reaction in which a single reactant gives two or more than two products.

3. Single replacement is a type of chemical reaction in which a more reactive element displaces the less reactive element from its slat solution.
4. Synthesis is a type of chemical reaction in which two or more than two reactants combine together to give a single product.
Silicon, it's bring brother would be the prime candidate, although its compounds are notably different from those of carbon.
Answer:
1 ) H2O 2) Hydrogen and oxygen 3) Compound
Explanation:
1) To write a chemical formula, you write the number of molecules of an element (2 hydrogen atoms + 1 Oxygen atom, or H2O). The letters represent the element's notation on the periodic table, while the number that follows it represents the number of atoms of that particular element within the compound. If there is no number that follows the letter, there is only one.
2) Letter "H" on the periodic table represents hydrogen, while "O" represents oxygen
3) You can tell that this is a compound because it is made of two or more elements found on the periodic table