MCAT Test Chemistry Ions.docx

Exam Tips and Final Review Ions We committed a number of ion names and formulas to memory – the anions possess either –ide (mostly atomic anions, such as chloride, Cl-) or –ate (molecular anions, such as SO42-, sulfate) suffixes. There are also many ‘in between’ molecular anions containing fewer, or occasionally more, oxygen atoms than the -ate ions. For example (from p 142): Ion formula Name or ion Cl- chloride ClO- Hypochlorite ClO2- Chlorite ClO3- Chlorate ClO4- Perchlorate The above table is worth memorizing, as there is likely to be one or two questions on the final regarding the ‘in between’ molecular anions of oxygen and chlorine. Example: Lithium chlorite has the formula: a. LiClO d. LiClO4 b. LiClO3 e. LiCl c. LiClO2 Solubility A solubility chart will NOT be provided for final, although you will have access to a periodic table. This is not a problem, however, as there are only two basic facts to remember: Chlorides are mostly soluble - AgCl(s) is an important exception Sulfates are mostly soluble – BaSO4 (s) is an important exception Use the above information to answer solubility questions on the final Final Exam Review Information Your ACS standardized final exam is a comprehensive, 70 question multiple choice (a – d) test. Questions are graded as either correct or incorrect. No points are subtracted for wrong guesses. There are two versions of the test, so your neighbors will have a different version of the test. I normalize your final exam score out of 70 to a score out of 200. This score out of 200 is included in your final course total. Tips A great way to ensure a good grade on your 101 and/or 102 final is to practice ACS style questions*. To help you with this, a pair of ACS study guides has been put on reserve in the library. Additionally, if you are going to take the MCAT or PCAT, the ACS guide is makes for an excellent resource for these tests' respective chemistry sections. *Ask me to tell you the ‘BB’ story Due to the number of questions set and the time allowed, most of the multiple choice questions you will meet on the final may be considered to be ‘lite’ versions of my midterm and quiz questions. The following tips will help you record a better score on your final: The test is cumulative, so review everything we have covered since the beginning for the course. Review all the topics, but concentrate on topics you have had difficulty with. Since the questions are not ‘super hard’, this will increase your number of correct answers. Do not fall in to the trap of studying what you are good at (you’ll get those questions right regardless, most likely), so preferentially study what you are ‘bad’ at. Try to answer the questions in order when using a scantron sheet. It is better to guess a wrong answer (and then come back to it) than risk systematically filling out ovals ‘a line out’. Work out the answers on the scratch paper provided, then check the possible answers provided. This will cut down on ‘red herring’ type errors (see below) Watch out for obvious ‘red herrings’, as illustrated by the following example. MOST questions DO NOT have a red herring, but a reasonable fraction do: Example: CO is the formula for: a. copper c. cobalt b. carbon monoxide d. Monocarbon monoxide Sample Final Exam Questions 1. In all neutral atoms, there are equal numbers of: a. electrons and protons c. electrons and neutrons b. protons and neutrons d. electrons and positrons 2. Which pair of particles has the same number of electrons: a. F-, Mg2+ c. P3-, Al3+ b. Ne, Ar d. Br-, Se 3. What is the mass percent of oxygen in Ca(NO3)2? a. 29.3 % c. 58.5 % b. 47.1 % d. 94.1% 4. A 24.0 g sample of carbon contains how many atoms: a. 6.02 x1023 c. 3.01 x1023 b. 1.20 x1024 d. 2.04 x1024 5. When 1.187 g of a metallic oxide is reduced with excess hydrogen, 1.054 g of the metal is produced. What is the metallic oxide? a. Ag2O c. K2O b. Cu2O d. Tl2O 6. A single molecule of a certain compound has a mass of 3.4 x10-22 g. Which value comes closest to the mass of a mole of this compound? a. 50 g c. 150 g b. 100 g d. 200 g 7. The electronic configuration for the Ca atom is: a. 1s22s22p63s23p64s23d2 c. 1s22s22p63s23p64s2 b. 1s22s22p63s2 d. 1s22s22p63s23p64s23d104p2 8. Two moles of any gas will occupy what volume at STP? a. 22.4 L c. 4.48 L b. 11.2 L d. 44.8 L Answers: 1. a. 5. b. 2. a. 6. d. 3. c. 7. c. 4. b. 8. d.