Chemistry Unit Test Review

Transcription

1 SNC 2DI Chemistry Unit Test Review Note: this review sheet only covers the second half of our chemistry unit. You should use our mid-unit test review sheet to recall concepts from the first half of the unit. Terms: Acid-Base Indicator Litmus Paper Universal Indicator Dissociate Neutralization Questions: 1. Provide two examples of processes in the body which rely on acids or bases. Digestion and breathing 2. What acid is essential for passing on genetic information? DNA deoxyribonucleic acid. 3. ph is a relative measurement of the number of what ion in solution? H + - hydrogen ions 4. What ph does a neutral solution have? 7 5. A change of one ph unit represents a change of strength of an acid or base of how many times? 10x 6. How much stronger is a base with a ph of 9 than a base with a ph of 8? 10x

2 7. How much stronger is an acid with a ph of 3 than an acid with a ph of 6? 10 x 10 x 10 = 1000 times stronger 8. What colour does blue litmus paper turn when dipped in an acidic solution? A basic solution? - Red - No colour change occurs when blue litmus paper is dipped in a base. 9. What colour does red litmus paper turn when dipped in a basic solution? An acidic solution? - Blue - No colour change occurs when red litmus paper is dipped in an acid. 10. What is universal indicator? A mixture of chemicals that changes colour through a wide range of ph values. 11. Explain how you would use universal indicator paper to test the ph of a solution. What benefit does universal indicator paper offer? Universal indicator paper is dipped into solution and the resulting colour change is compared to a chart of ph values to determine the ph of the solution. The benefit of universal indicator paper is that it provides a more accurate measurement of ph than litmus paper. Universal indicator paper can be used to determine a ph value, whereas litmus paper can only determine if a solution is acidic or basic. 12. What is the benefit of using a ph meter to measure the ph of a solution? Is it more accurate than universal indicator paper?

3 A ph meter will provide a measurement of the ph of a solution to two decimal places. This information is very useful when doing calculations involving ph. It is far more accurate than universal indicator paper. 13. Create a table to organize the similarities and differences between the properties of acids and bases. Acids Bases Similarities Dissolve in water Dissolve in water Conduct electricity in aqueous solution Conduct electricity in aqueous solution Can irritate or burn skin Can irritate or burn skin Differences Taste sour Taste bitter Do not feel slippery Feel slippery ph less than 7 ph greater than 7 Turn blue litmus red Turn red litmus blue Release hydrogen ions (H + ) in solution Release hydroxide ions (OH - ) in solution Corrode metals Do not corrode metals React with metals to produce a compound and hydrogen gas Do not react with metals to produce a compound or hydrogen gas 14. While working in the lab you come across two unknown solutions. You believe one is an acid and one is a base but you aren t sure. You go looking for your ph paper and realize you ran out. In your frustration you knock over one of the unknown solutions. While cleaning up the mess you notice that the lab bench and floor have become very slippery. Which solution did you spill? The acid or the base? Since bases feel slippery and acids do not, it must have been the base. 15. You have two unknown solutions. One is an acid and the other is a base. You have no ph paper, meter, or other lab equipment. All you have is a piece of metal and lots of time. How could you determine which solution is which?

4 Since acids will corrode metals and bases won t you could pour some of each solution on two different areas of the metal and see which area corrodes over time. 16. How can you identify an acid when given the name? When given the chemical formula? - The name will end with the word acid. - The chemical formula will start with H (hydrogen) or end with COOH. 17. How can you identify a base when given the name? When given the chemical formula? - The name will end with the word hydroxide. - The chemical formula starts with a cation (metal or ammonium ion) and ends with OH. 18. Which of the following compounds are acids? Which are bases? Which are neither? HClO Cr(OH) 2 CsOH Sn 3 As 4 Ni(OH) 2 H 2 S 2 O 7 H 4 P 2 O 6 RbOH Mg 3 (PO 5 ) 2 Al 2 O 3 CH 2 (COOH) 2 CH 3 COOH Mn(OH) 2 Li 2 S HBr KOH Sb 2 (SO 4 ) 5 C 5 H 11 COOH BN Mn(OH) 7 Acids Bases Neither HClO H 2 S 2 O 7 H 4 P 2 O 6 CH 2 (COOH) 2 CH 3 COOH HBr C 5 H 11 COOH Cr(OH) 2 CsOH Ni(OH) 2 RbOH Mn(OH) 2 KOH Mn(OH) 7 Sn 3 As 4 Mg 3 (PO 5 ) 2 Al 2 O 3 Li 2 S Sb 2 (SO 4 ) 5 BN 19. Provide the chemical name and chemical formula for each of the following acids or bases. Indicate which is an acid and which is a base and one common use of each. a. Muriatic acid b. Ammonia solution c. Formic acid d. Acetic acid e. Milk of magnesia f. Slaked lime g. Caustic soda h. Battery acid i. Stomach acid

5 j. Hydrated lime Chemical Formula Acid or Base Chemical Name Common Name Uses HCl Acid hydrochloric acid muriatic acid, cleaning concrete; making stomach acid other chemicals H 2 SO 4 Acid sulphuric acid battery acid car batteries; making fertilizer; manufacturing HCOOH Acid methanoic acid formic acid dyeing wool; tanning leather CH 3 COOH Acid ethanoic acid acetic acid diluted to make vinegar; making plastic; added to foods for flavour NaOH Base sodium hydroxide caustic soda NH 4 OH Base ammonium hydroxide ammonia solution Ca(OH) 2 Base calcium hydroxide slaked or hydrated lime Mg(OH) 2 Base magnesium hydroxide milk of magnesia cleaning drains; making soaps, plastics and textiles; controlling pollution cleaning windows; making dyes, plastic, and glass; controlling pollution making glass, cement, and steel; correcting acidic soil; removing hair; making baby formula treating indigestion; bleaching clothes; treating wastewater; making articles fire resistant. 20. Give three examples of common household products which are acids. Vinegar, toilet bowl cleaner, toothpaste 21. Give three examples of common household products which are bases. Window cleaner, bleach, baking soda There are other products which could be listed for question 20 or 21. Check your lab! 22. Write the name of each of the following acids. a. HCl hydrochloric acid b. HClO 3 chloric acid c. HNO 3 nitric acid

6 d. H 2 CO 3 carbonic acid e. H 3 PO 3 phosphoric acid f. HBr hydrobromic acid g. HI hydroiodic acid h. HF hydrofluoric acid i. H 2 SO 4 sulfuric acid 23. Write the name of each of the following bases. a. Al(OH) 3 aluminum hydroxide b. LiOH lithium hydroxide c. KOH potassium hydroxide d. Sr(OH) 2 strontium hydroxide e. Ba(OH) 2 barium hydroxide f. AgOH silver hydroxide g. NaOH sodium hydroxide h. Zn(OH) 2 zinc hydroxide i. Mg(OH) 2 magnesium hydroxide 24. Write the general chemical equation for a neutralization reaction. HB + XOH XB + H 2 O 25. What are the reactants of a neutralization reaction? What are the products? Reactants = acid + base Products = salt + water 26. Explain what happens when an acid or base is put into solution. (Hint: what happens to the ions?) The cation and anion dissociate (separate). 27. Write the balanced chemical equations for the following neutralization reactions. a. aqueous sulfuric acid + aqueous strontium hydroxide H 2 SO 4 (aq) + Sr(OH) 2 (aq) SrSO 4 (aq) + 2 H 2 O(l)

7 b. aqueous hydroiodic acid + aqueous zinc hydroxide 2 HI(aq) + Zn(OH) 2 (aq) ZnI 2 (aq) + 2 H 2 O(l) c. aqueous nitric acid + potassium hydroxide HNO 3 (aq) + KOH(aq) KNO 3 (aq) + H 2 O 28. What are three applications of neutralization reactions? - Produce salts for pharmaceuticals. The salts can be collected by filtering them out of solution. - In medicine to treat acid reflux. Acid reflux can be treated with antacid tablets which are bases. By consuming the base the user neutralizes the acid in their stomach and relieves the pain from acid reflux. - In food production and packaging. Acids and bases can be used as preservatives or to alter the flavour of foods.