CHEM 1211K Test I. 2) Which one of the following is a pure substance? A) salt water B) concrete C) milk D) wood E) elemental copper

Transcription

1 CHEM 1211K Test I MULTIPLE CHOICE. (3 points each) 1) Consider a mixture consisting of sand in salt water. This mixture could be separated into its three components (sand, salt, and water) by first the mixture and then the remaining mixture. A) filtering, filtering B) filtering, distilling C) distilling, distilling D) evaporating, grinding E) distilling, filtering 2) Which one of the following is a pure substance? A) salt water B) concrete C) milk D) wood E) elemental copper 3) Which states of matter are significantly compressible? A) liquids and gases B) gases only C) solids and liquids D) liquids only E) solids only 4) If matter is uniform throughout and cannot be separated into other substances by physical means, it is. A) a heterogeneous mixture B) either an element or a compound C) an element D) a compound E) a homogeneous mixture 5) Which one of the following is an intensive property? A) heat content B) amount C) temperature D) mass E) volume 6) Which of the following are chemical processes? A) rusting of a nail B) freezing of water C) decomposition of water into hydrogen and oxygen gases D) compression of oxygen gas E) A and C 7) The temperature of 25 o C is in Kelvins. A) 103 B) 138 C) 248 D) 298 E) 166 8) x 10-4 L = ml A) B) C) x 10-7 D) E) x 10 7

2 9) The density of silver is 10.5 g/cm 3. What would be the mass (in grams) of a piece of silver that occupies a volume of 23.6 cm 3? A) 0.445g B) 248g C) 2.25g D) 112g E) 23.6g 10) Accuracy refers to. A) how close a measured number is to the calculated value B) how close a measured number is to zero C) how close a measured number is to infinity D) how close a measured number is to the true value E) how close a measured number is to other measured numbers 11) A wooden object has a mass of g and occupies a volume of ml. What is the density of the object determined to an appropriate number of significant figures? A) 8 x 10-1 g/ml B) 7.9 x 10-1 g/ml C) 7.86 x 10-1 g/ml D) x 10-1 g/ml E) x 10-1 g/ml 12) The number with the most significant zeros is. A) B) C) D) E) x ) The recommended adult dose of Elixophyllin, a drug used to treat asthma, is 6.0 mg/kg of body mass. Calculate the dose in milligrams for a 115-lb person. 1 lb = g. A) 1.5 B) 24 C) 313 D) 1,521 E) 3.1 x ) What decimal power does the abbreviation Milli represent? A) 1 x 10-3 B) 1 x 10 9 C) 1 x 10-6 D) 1 x 10 3 E) 1 x ) Methane and ethane are both made up of carbon and hydrogen. In methane, there are 12.0 g of carbon for every 4.00 g of hydrogen, a ratio of 3:1 by mass. In ethane, there are 24.0 g of carbon for every 6.00 g of hydrogen, a ratio of 4:1 by mass. This is a statement of the law of. A) octaves B) constant composition C) conservation of matter D) conservation of mass E) multiple proportions 16) In the symbol below, X = 13 6 X A) N B) C C) Al D) K E) not enough information 17) The charge on an electron was determined in the. A) atomic theory of matter B) Rutherford gold foil experiment C) Millikan oil drop experiment D) Dalton atomic theory E) cathode ray tube, by J. J. Thompson

3 18) and reside in the atomic nucleus. A) Protons, electrons B) Protons, neutrons C) Electrons, neutrons D) none of the above E) Neutrons, only neutrons 19) In the Rutherford nuclear-atom model,. A) the light subatomic particles, protons and neutrons, reside in the nucleus B) the three principal subatomic particles (protons, neutrons, and electrons) all have essentially the same mass C) the heavy subatomic particles, protons and neutrons, reside in the nucleus D) the three principal subatomic particles (protons, neutrons, and electrons) all have essentially the same mass and mass is spread essentially uniformly throughout the atom E) mass is spread essentially uniformly throughout the atom 20) Cathode rays are deflected away from a negatively charged plate because. A) they are negatively charged particles B) they are not particles C) they are positively charged particles D) they are neutral particles E) they are emitted by all matter 21) Of the following, the smallest and lightest subatomic particle is the. A) nucleus B) proton C) neutron D) electron E) alpha particle 22) The atomic number indicates. A) the number of different isotopes of an element B) the number of neutrons in a nucleus C) the number of atoms in 1 g of an element D) the total number of neutrons and protons in a nucleus E) the number of protons or electrons in a neutral atom 23) Which combination of protons, neutrons, and electrons is correct for the isotope of copper, Cu? A) 34 p +, 34 n o, 29 e - B) 29 p +, 34 n o, 29 e - C) 63 p +, 29 n o, 63 e - D) 29 p +, 29 n o, 63 e - E) 34 p +, 29 n o, 34 e - 24) Which one of the following is not one of the postulates of Dalton's atomic theory? A) During a chemical reaction, atoms are changed into atoms of different elements. B) Each element is composed of tiny, indivisible particles called atoms. C) Compounds are formed when atoms of different elements combine. D) Atoms of an element are not changed into different types of atoms by chemical reactions. E) All atoms of a given element are identical to each other and different from those of other elements. 25) Different isotopes of a particular element contain the same number of. A) subatomic particles B) protons, neutrons, and electrons C) neutrons D) protons and neutrons E) protons

4 Problems (SHOW ALL WORK ON THIS PAPER) (5 points) The density of benzene at 15 o C is g/mL. Calculate the mass of L of benzene. mass D = volume mass g / ml = (0.1500L)( 1000 ml ) 1L mass= g / ml ( L( 1000mL ) 1L (10 points) A children s pain relief elixir contains 80mg acetaminophen per 0.50 teaspoon. The dosage recommendation for a child who weight between 24 and 35 lb is 1.5 teaspoons. What is the range of acetaminophen dosages, expressed in milligram acetaminophen/ kg body weight, for children, who weigh between 24 and 35 lb? 80mg 1.5tsp 0.50tsp = 240mg 25lbs g 1kg 24lbs 1lb 1000g = kg 240mg drug dose= kg = 22.1mg / kg 35lbs g 1kg 35lbs 1lb 1000g = kg 240mg drug dose= kg = 15.1mg / kg

5 (10 points) Only two isotopes of copper occur naturally. 63 Cu (mass = amu: abundance 69.17%) and 65 Cu (mass = , abundance 30.83%). Calculate the atomic weight (average atomic mass) of copper. This is a homework problem. - weighted average wt. average= ( amu (30.83/100)) + ( amu (69.17 /100)) = 63.55amu