QUESTION 38 When using a digital balance, the student should A. record the digits given plus one estimated digit. B. round the displayed mass to a whole number. C. round the displayed mass to the tenths place. D. record all of the digits displayed by the instrument. QUESTION 37 A student is using a digital meter to measure the temperature and pressure of an enclosed gas. He notices that the temperature reading remains constant, but the pressure gradually decreases to about 1 atm. What should he conclude? A. There is a leak in the apparatus. B. The volume of gas is too small for an accurate reading. C. The gas is not ideal. D. He cannot reach a conclusion without knowing the mass of the gas. E. The LabQuest needs to be recalibrated. QUESTION 36 Balance errors are the most common student mistakes. Which statement is not a proper weighing technique? A. Always zero the balance before beginning a mass determination. B. Always weigh objects in a container rather than directly on the balance pan. C. Always weigh objects that are at room temperature. D. Always use the same balance throughout an experiment.. E. Always move the balance to a safe and level location on the lab bench. QUESTION 30 Name the following compound. A. Heptane B. 2,3-dimethylpentane C. 3,4-dimethylpentane D. 2-methyl-3-methylhexane E. 2,4-dimethylpropane QUESTION 29 Identify the formula for an alkane: A. CnH2n+2 CnH2n+4 B. C. D. E. CnH2n CnH2n-4 CnH2n-2 QUESTION 28 in Organic Chemistry, the reactivity of molecules is primarily determined by the molecules. A. alleles B. bacteria C. functional groups D. metal ions contained in the QUESTION 27 A system with enthalpy and A. negative/positive B. positive/positive C. negative/negative D. positive/negative entropy will never be spontaneous.