Which of the following is a synthesis reaction? BaO + CO2 → BaCO3 CH4 + O2 → CO2 + H2O FeCO3 → FeO + CO2 2NH3 → 2N2 + 3H2 Question 2(Multiple Choice Worth 4 points) (04.02 LC) What is true of synthesis and decomposition reactions? Synthesis reactions require more energy than decomposition reactions. Synthesis reactions produce more products than decomposition reactions. Synthesis reactions are the opposite of decomposition reactions. Synthesis reactions have fewer reactants than decomposition reactions. Question 3(Multiple Choice Worth 4 points) (04.02 MC) An unbalanced chemical equation is shown: 2NaN3 → 2Na + N2 Which of the following statements explains why the equation is not balanced? Four molecules of N2 should be produced during the decomposition. Three molecules of N2 should be produced during the decomposition. Four molecules of N2 should be produced during the synthesis reaction. Three molecules of N2 should be produced during the synthesis reaction. Question 4(Multiple Choice Worth 4 points) (04.02 MC) Which chemical equation correctly represents the reaction that takes place when nitrogen gas and hydrogen gas are formed as ammonia decomposes? N(g) + H3(g) → NH3(g) 2N(g) + 3H2(g) → 2NH3(g) 2NH3(g) → N2(g) + 2H3(g) 2NH3(g) → N2(g) + 3H2(g) Question 5 (True/False Worth 2 points) (04.02 LC) A synthesis reaction can be identified because it only has pure elements on the left side of the arrow and compounds on the right side of the arrow. True False Question 6 (True/False Worth 2 points) (04.02 LC) The reaction K(s) + 2H2O(l) → 2KOH(aq) + H2(g) is a decomposition reaction. True False

Explanation: 1. In synthesis reactions a single product is formed from 2 or more reagents. In this case BaCO3 is formed from and BaO and CO2. The other reactions are examples of decomposition

2. A decomposition reaction is that in which a single reagent is 'broken' or divided into other compounds or elements, while synthesis as explained above is a formation reaction.

3. A balanced reaction is that in which there are the same amount of atoms in left and in the right side of the arrow no matter if they are forming different molecules. In this reaction, there are 2 atoms of Na and 6 atoms of N (2x3) on the left of the arrow, so there should be in 2 atoms of Na on the right side as shows the equation and 3 molecules of N2 which equals 6 atoms of N (3x2)

4. If NH3 ammonia is decomposing, it should be on the left side of the arrow, while the products go on the right side. In this case products are gases of elements which have basic formula X2 (H2 and N2) and it's important also to check if the equation is balanced.

5. A synthesis reaction can take place between elements or compounds as long as they can formed a new compound. And example is the answer of the first question.

6. In this reaction, two compounds react and form two different compounds. It can be considered decomposition, is called double replacement.