Practice Questions Option D section 5-7

Review: D2 35. Antacids can be taken for indigestion caused by excess acidity. (a) Identify the substance responsible for the low pH value of the liquid in the human stomach. (1) (b) Two active ingredients in antacids are Mg(OH)2 and NaHCO3. Write an equation to show how each ingredient can relieve indigestion. (2) (c) Three antacid preparations contain 0.01 mol of one of the following – Mg(OH)2, Al(OH)3 and NaHCO3. Identify the most effective antacid. Give a reason for your choice, with reference to the antacid formula. (2) HCl Mg(OH)2 + 2HCl  MgCl2 + 2HOH Al(OH)3 + 3HCl  AlCl3 + 3HOH Al(OH)3; it will neutralize 3 molecules of HCl/0.03 moles HCl

Review: D3 Mild: intercept pain at the source 12. The structures of some analgesics are shown in Table 21 of the Data Booklet. Refer to this table when answering parts (b) and (c) of this question. Explain the difference in the method of action of mild analgesics and strong analgesics. (2) State the name of the nitrogen-containing functional group in each of the following. (2) Paracetamol ................................................................................................................ Heroin ......................................................................................................................... (c) Naturally-occurring morphine can be converted into synthetic heroin by reaction with ethanoic acid. Identify the group in the morphine molecule that reacts with ethanoic acid, the name of the type of reaction and the other product of the reaction. (3) Group in morphine molecule ....................................................................................... Type of reaction ........................................................................................................... Other product of reaction ............................................................................................. Mild: intercept pain at the source Strong: interact with/block receptor sites in the brain Amide (tertiary) amine OH/alcohol/hydroxyl/phenol (all mean the same thing) Esterification/condensation Water/H2O

Review, D4 20. Acidified potassium dichromate(VI) is commonly used in roadside tests for ethanol in the breath of persons operating motor vehicles. It reacts with the ethanol present to form ethanoic acid. (a) State the function of potassium dichromate(VI) and give the colour change that takes place in this reaction. (2) (b) Identify two other methods for the detection of ethanol in a person’s breath or blood that are considered to be more accurate. (2) (c) State one harmful effect of aspirin that is more likely to occur if it is taken with ethanol. (1) Oxidizer; orangegreen Gas/liquid chromatography; infrared spectroscopy Stomach bleeding/ulcers

#1: D5 23. (a) State the name of the class of drugs with effects similar to that of adrenaline. Outline one effect of these drugs on humans. (2) (b) (i) Identify the stimulant responsible for addiction to smoking tobacco. (1) (ii) Describe 2 short-term effects of smoking tobacco. (2) (iii) Describe two long-term effects of smoking tobacco, other than addiction. (2) Stimulants 1: Increased heart rate/blood pressure/breathing rate, dilation of pupils, sweating Nicotine 2: Increased heart rate/blood pressure/concentration, decreased urine production Increased cancer/stroke/heart disease risk, ulcers, emphysema, bronchitis, coughing, bad breath, yellowing teeth/fingers

#2: D5 11. Methylamphetamine (also known as methamphetamine or “speed”) and caffeine are stimulants with the following structures. Methamphetamine: Caffeine: (a)(i)On the structure for methylamphetamine above, draw a ring around the amine group. (1) (ii)Determine whether both amine groups in caffeine are primary, secondary or tertiary. (1) (b)Caffeine contains the group R-CONH2 . State the general name for this functional group. (1) Both= tertiary Amide (also called a “peptide”)

#3: D6 14.(a) Describe the differences between bacteria and viruses, by referring to their structures and the way they multiply. (4) (b) Outline two ways in which antiviral drugs work. (2) Bacteria are large/viruses are smaller; bacteria are cellular/viruses are non-cellular; bacteria have a cell wall/cytoplasm/organelles Bacteria can feed/excrete/respirate/grow outside cells (opposite for viruses Viruses insert DNA/RNA into cells/rely on a host cell to reproduce; bacteria multiply by cell division/mitosis/meiosis (ANY 4, 1 POINT EACH) Alter host cell’s genetic material; prevent virus from multiplying; alter the viruses bonding site on the host cell

#4: D6 Penicillin G was the first antibiotic used to fight infections. The structure of this antibiotic is as follows: (a) Determine the molecular formula of penicillin G. (1) (b) State 2 reasons for modifying the side chain in penicillin G (2) (c) Describe the mode of action of penicillin in preventing the growth of bacteria. (2) (d) Discuss two effects of over prescription of penicillin to humans. (2) (b) Decrease acid sensitivity so it can be swallowed; decrease deactivation by penicillinase C16H18O4N2S Interferes with cell wall formation (decreases the cross-linking); cells fill with water and burst 2: makes pennicillin less effective; resistant strains of bacteria can develop; destroys useful bacteria

#5: D5 (c) Ii Mimic the effect of adrenaline (any 2) stimulate nervous system; speed up heart rate, increase sweat production; increase breathing rate #5: D5 Caffeine is a stimulant with the following structure. Determine whether both amine groups in caffeine are primary, secondary or tertiary. (1) Caffeine contains the group R–CONH2. State the general name for this functional group. (1) Tablets of the drug Ecstasy are sometimes contaminated with a substance called 4−MTA. (i) Ecstasy and 4-MTAare sympathomimetic drugs. Identify the structural similarity between the two drugs and epinephrine (adrenaline), the structure of which is given in Table20 of the Data Booklet (1) (ii) Outline what is meant by the term sympathomimetic drug and state 2 examples of short-term effects sympathomimetic drugs have on the body. (3) (iii) State 1 example of a long-term effect of taking stimulants. (1) tertiary amide All have a benzene ring attached to 2 carbon atoms and 1 amine group