159 Created by Master Student Chemistry Practice Test #8 1 / 30 Gives the mass per unit volume Density A solid Volume Weight Matter (A) The mass per unit volume is the definition of density. 2 / 30 A radioactive material is undergoing nuclear decay. After 40 minutes, 25 percent of the sample remains. What is the half-life of the sample? 10 minutes 20 minutes 40 minutes 80 minutes 160 minutes The half-life of a radioactive material is the time that it takes for half of the sample to decay. After 1 half-life, 50 percent of this sample remains; after 2 half-lives, 25 percent remains. If two half-lives are 40 minutes, then 1 half-life is 20 minutes long. 3 / 30 The most unreactive family of elements Alkali metals Alkaline earth metals Noble gases Halogens Transition metals The atoms of noble gas elements have filled valence shells and, therefore, are extremely unreactive-more so than any other family. 4 / 30 In an effort to speed up a reaction between a solid and a gas one would not: make an effort to concentrate the reactants as best as possible add a catalyst cool the reaction down increase the pressure on the system use a powdered solid instead of one big lump of the same solid 0 5 / 30 Indicates a red flame when ionized with a Bunsen burner 0.1 M MgCl2 0.1 M HClO4 0.1 M NH4OH 0.1 M KOH 0.1 M LiNO3 Certain metal ions produce characteristic colors when ionized in a flame-that's how fireworks are made to have different colors. Here are the most common ions, and the color they produce. 6 / 30 Which pair of symbols below show different isotopes of the same element? 3918A and 3919R 6027X and 5928Y 126L and 146L 3717X and 3717X 32E and 31G 0 7 / 30 After 62.0 hours, 1.0 gram remained unchanged from a sample of 42K (half-life is 12.4 hours). What was the mass of b 42K in the original sample? 64 grams 32 grams 16 grams 8 grams 4 grams 0 8 / 30 How many moles of electrons are required to reduce 2.93 grams of nickel ions from melted NiCl2? (Molar mass of Ni = 58.7 g/mol) 0.05 0.1 1 1.5 2 (B) The reaction is 9 / 30 In which of the following compounds are hydrogen bonds between molecules the strongest? HF HCl HBr HI HAt 0 10 / 30 In this equation: Al(OH)3 + H2SO4 <=> Al2(SO4)3 + H2O, the whole-number coefficients of the balanced equation are 1, 3, 1, 2 2, 3, 2, 6 2, 3, 1, 6 2, 6, 1, 3 1, 3, 1, 6 (C) The balanced equation has the coefficients 2, 3, 1, and 6: 2Al(OH)3 + 3H2SO4<=> Al2(SO4)3 + 6H2O. 11 / 30 Attracts atoms of hydrogen to each other in an H2 molecule Hydrogen bonding Ionic bonding Metallic bonding Nonpolar covalent bonding Polar covalent bonding Don't be fooled by (A). Hydrogen bonds occur between, not within molecules. A hydrogen molecule consists of nonmetal hydrogen atoms in a bond. Nonmetals form covalent bonds, and identical nonmetal atoms form nonpolar covalent bonds. 12 / 30 What should you do if a chemical splatters into your eye? The rule is to add concentrated acid to water slowly. The rule is to add water to the concentrated acid slowly. Carefully replace unused or excess chemicals into their properly labeled containers from which they came. Flush eyes with water at the eyewash fountain for at least 15 minutes, and then report the accident for further help. Dispose of chemicals in the proper places and following posted procedures. Do not return them to their original containers. (D) It is essential to get your eyes washed of any chemicals. Know where the eyewash fountains are, and know how to use them. 13 / 30 In general, when metal oxides react with water, they form solutions that are acidic basic neutral unstable colored (B) Metal oxides are generally basic anhydrides. 14 / 30 Contains up to ten electrons 1s 2s 3s 3p 3d (E) The five 3d orbitals can contain a total of ten electrons. 15 / 30 Which one of the following polymers is synthetic? Nucleic acids Plastic Proteins Cellulose Starch 0 16 / 30 Which pairing is not a set of conjugates? OH1- and H2O HC2H3O2 and C2H3O21- HCl and Cl1- NH3 and NH41+ H2SO4 and SO42- 0 17 / 30 Allows copper to conduct electricity Hydrogen bonding Ionic bonding Network bonding London dispersion force Metallic bonding Solid copper is held together by metallic bonding. When elements are held together by metallic bonds, positively charged nuclei float in a sea of mobile electrons. The electrons move freely from nucleus to nucleus. This electron mobility is responsible for the distinctive properties of metals such as conductivity and malleability. 18 / 30 Exist as diatomic molecules at room temperature Alkali metals Alkaline earth metals Noble gases Halogens Transition metals Did you remember this statement: Have No Fear Of Ice Cold Bears? If so, you'd realize that some of the most common diatomic molecules are halogens-F2, Cl2, Br2, and I2. 19 / 30 In the artificial transmutation 94Be + X <=> 63Li + 42He, the particle represented by the letter X is a(n) deuteron proton alpha particle beta particle positron 0 20 / 30 Increased with the addition of a catalyst Standard voltaic potential Entropy Enthalpy Reaction rate Gibbs free energy A catalyst decreases the activation energy, or energy barrier, that must be overcome for reactants to become products. In this way, catalysts increase the rate of chemical reactions. 21 / 30 What is the total number of atoms represented in one molecule of (CH3)2NH? 5 8 9 10 12 0 22 / 30 Choose the answer below that accurately describes the correct molecular shape for the molecule XeOF4. Tetrahedral Trigonal pyramidal Trigonal bipyramidal Square pyramidal Flat First, draw the Lewis dot structure for XeOF4. 23 / 30 Which of the following atoms has the largest second ionization energy? Silicon, Si Calcium, Ca Chlorine, Cl Iron, Fe Sodium, Na Ionization energies get very large once we try to remove core electrons, which are attracted more strongly to the nucleus than valence electrons. So an atom with a very high second ionization energy would be expected to have just 1 valence electron: The second electron to be removed from such an atom would have to be a core electron. Among the choices, only sodium atoms have a single valence electron. 24 / 30 The daughter nucleus formed when 18F undergoes positron emission is 14N 16O 18O 19F 20Ne Positron emission is a type of beta decay. During beta decay, nuclear mass remains constant. Therefore, choice (C) is the only possible answer. 25 / 30 Which molecule is a polar molecule? N2 H2O CH4 CO2 KCl 0 26 / 30 The expression that can be used to designate a linear nonpolar molecule that contains polar bonds H2(g) CO2(g) 2N2O(g) 2NaCl (aq) H2SO4(dilute aq) (B) The molecular structure of carbon dioxide is O=C=O, where the oxygens are 180 degrees apart and, although the bonding is polar to the carbon, counteract each other to constitute a nonpolar molecule. 27 / 30 A solid, liquid, and gas can exist together at the sublimation point triple point boiling point freezing point melting point 0 28 / 30 Will have the lowest freezing point A 0.01-molar solution of HNO3 A 0.01-molar solution of HC2H3O2 A 0.01-molar solution of Cu(NO3)2 A 0.01-molar solution of NaNO3 A 0.01-molar solution of NaOH Freezing point depression is a colligative property, which means that it depends only on the number of particles in a solution, not on their identities. For every unit of Cu(NO3)2 in a solution, 3 particles are produced: 1 Cu2+ and 2 NO3?. For all of the other choices, each unit in solution produces only 2 particles. 29 / 30 Which gas is expected to have the highestrate of effusion? O2 F2 H2O He CH2 0 30 / 30 Which of the following changes in the experiment shown in question 12 would cause the pressure in the glass container to vary from that shown? Use a U-tube of a greater diameter and maintain the height of mercury. Increase the temperature of gas in the tube. Increase the length of the upper portion of the right side of tubing. Use a U-tube of a smaller diameter and maintain the height of mercury. Replace the flask with one that has the same volume but has a flat bottom. (B) The only change listed that would change the pressure of the gas inside the flask is to increase the temperature of the gas. This would cause the pressure to rise. Your score is The average score is 63% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Previous Quiz Next Quiz
