Chemical reactions

1. List different observations that usually signify a chemical change. Color change, temp change, gas production, pH change, production of a precipitate

2. What does every chemical change involve? The production of a new substance

3. What is a precipitate? A solid that forms from the reaction of two liquids. “S” represents the precipitate in a chemical equation.

4. What does the law of conservation of mass state? Mass is neither created or destroyed during a chemical reaction.

5. Why do chemists use a chemical equation? To represent the chemical reaction taken place and to show that the law of conservation of mass/matter is being met.

6. List two ways you could “read” the arrow in a chemical equation. Yields or produces

7. What is a chemical equation? A symbolic representation of a chemical reaction, showing the reactants and products.

8. What does a skeleton equation NOT show? The balanced reaction – the total amount of atoms present

9. In an equation, what is meant by… (s)?solid …(l)? liquid …(g)?gas …(aq)?aqueous

10. What are coefficients? Numbers placed in from of compounds or elements to show the law of conservation of mass is being met. Balancing the reaction

11. A balanced equation is one in which each side of the equation has… same number of atoms

12. If a coefficient isn’t written, it is understood to be __1_.

13. List the five general types of reactions. Single replacement, double replacement, synthesis, decomposition, combustion

14. What is a synthesis reaction? Two singe elements combine to form one product

15. In all synthesis reactions, the product is a compound__.

16. What is a decomposition reaction? 1 compound decomposes into its elements

17. Decomposition reactions involve… 1…how many reactants? 2…how many products?

18. What is a single-replacement reaction? A single replacement reaction is a reaction where a single element reactant replaces a like element in a compound, which is also a reactant

19. How can you identify a single-replacement reaction? The reactants will always be a single element and a compound

20. On the activity series, a reactive metal will replace any metal listed below it.

21. What happens to the activity of the halogens as you go down the group (look at the activity series) reactivity decreases

22. What is a double-replacement reaction? A double replacement reaction is one that starts with two ionic compounds and the compounds switch partners creating two new compounds

23. What is a combustion reaction? A combustion reaction starts with a hydrocarbon and oxygen and always produces water and carbon dioxide

24. What is a hydrocarbon? A compound that consists of only carbon and hydrogen

25. The combustion of a hydrocarbon produces ____carbon dioxide_____ and ___water______.

26. What does a balanced chemical equation allow you to determine? The number of atoms of each element contained in the reaction

27. The letters “aq” mean the substance has been dissolved in water.