ch8 rev2 answers

Ch8 rev ans

1. Balance and classify: 2C₆H₁₄ + 19O₂ = 12CO₂ + 14H₂O combustion

2. First use _oxidation__ numbers to get the correct _subscripts_ in the chemical formula

3. Once the chemical formula is correct, adjust the _coefficients_ to balance the equation

4. List the 7 diatomic elements. H,O,N, F,Cl,Br, I. What does diatomic mean? 2 atoms per molecule

5. According to _law of conservation of mass_ the mass of the reactants always_equals_ the mass of the products.

6. _catalysts_ are placed above the arrow in an equation. They _speed up_ a reaction, but are not used up.

7. Classify: A + B = AB synthesis/ CD + AB = AD + CB double displacement / AB = A + B decomposition / A + CD = AD + C single displacement

8. What is the name of solid that falls out of a solution in a rxn? precipitate What class of rxn? double displacement

9. Breaking apart by electrical current is called what? electrolysis What class of rxn? decompostion

10. What do you get when you decompose a binary compound? 2 elements

11. If a gas is produced in a chemical rxn, what will you see? bubbles

12. Metals plus HCl produce metal compounds and what? hydrogen gas

13. How are Br and I alike? diatomic, reactive nonmetals, halogens

14. Balance and classify: N₂ +3 H₂ =2NH₃

15. Write balanced chemical equations if there is a rxn; if no rxn write the reactant formulas and ‘nr’

a. calcium plus oxygen 2Ca + O₂= 2CaO b. sodium chloride plus florine 2NaCl + F₂ = 2NaF + Cl₂ c. sodium and water 2Na + 2H₂O= 2NaOH + H₂ d. potassium floride and chlorine nr e. aluminum and strontium nitrate nr f. copper and water nr g. iron III and sulfuric acid 2Fe + 3H₂SO₄ = Fe₂(SO₄)₃ + 3H₂ h . platinum and oxygen nr i. bismuth and hydrochloric acid nr k. zinc and Nickel II oxide Zn + NiO= ZnO + Ni

16 Write a balanced chemical equation for the synthesis of magnesium oxide include states. 2Mg(s) + O₂(g) must be heated= 2MgO(s)

17 Will a reaction happen when barium nitrate and sodium sulfate solutions are mixed? why or why not? write chemical equations with states if reaction happens. yes, one of the new possible combinations, barium sulfate is insoluble (see solubility table) Ba(NO₃)₂ (aq) + Na₂SO₄(aq) = BaSO₄(s) = 2NaNO₃(aq)

18. Write balanced chemical equation for the combustion of C₁₁H₂₄ + 17O₂= 11CO₂ + 12H₂O

19. give examples or define: endothermic gets cooler, exothermic gets warmer, activation energy match/striker, limiting reactant runs out causing reaction to stop