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- Aerogels are transparent, low-density materials that are nearly 99.8% empty space and excellent insulators against hot and cold. The density of a silica-based aerogel is 3.0 mg/cm3. What is the density in units of g/m3? (LO 1.17) (a) 3.0 * 10-3 g/m3 (b) 3.0 * 101 g/m3 (c) 3.0 g/m3 (d) 3.0 * 103 g/m3
Problem 15
- Which block in each of the following drawings of a balance is more dense, red or green? Explain.
Problem 27
- What is the temperature reading on the fol-lowing Celsius thermometer? How many sig-nificant figures do you have in your answer?
Problem 28
- How many milliliters of water does the graduated cylinder in (a) contain, and how tall in centimeters is the paper clip in (b)? How many significant figures do you have in each answer?
Problem 29
- Assume that you have two graduated cylinders, one with a capacity of 5 mL (a) and the other with a capacity of 50 mL (b). Draw a line in each, showing how much liquid you would add if you needed to measure 2.64 mL of water. Which cylinder will give the more accurate measurement? Explain.
Problem 30
- The following cylinder contains three liquids that do not mix with one another: water (density = 1.0 g/mL), vegetable oil (density = 0.93 g/mL), and mercury (density = 13.5 g/mL). Which liquid is which?
Problem 31
Problem 32a
The following statements pertain to the development of the theory of combustion by the French chemist Lavoisier in the eighteenth century. Match the statement with the appro-priate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method (a) A metal is burned in a closed container, and the change in mass of the solid and volume of the gas is measured.
Problem 32b
The following statements pertain to the development of the theory of combustion by the French chemist Lavoisier in the eighteenth century. Match the statement with the appro-priate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method (b) Oxygen gas combines with a substance during its combustion.
Problem 32c
The following statements pertain to the development of the theory of combustion by the French chemist Lavoisier in the eighteenth century. Match the statement with the appro-priate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method (c) Combustion of a metal in a closed container ceases after a length of time.
Problem 33a
The following statements pertain to the development of the theory of the structure of DNA. Match the statement with the appropriate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method. (a) Two strands of DNA wind around one another in a helical structure.
Problem 33b
The following statements pertain to the development of the theory of the structure of DNA. Match the statement with the appropriate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method. (b) In a sample of DNA, there are equal amounts of the bases A and T and equal amounts of the bases C and G.
Problem 33c
The following statements pertain to the development of the theory of the structure of DNA. Match the statement with the appropriate step (observation, hypothesis, experiment designed to test hypothesis) in the scientific method. (c) Direct X rays at a sample of crystallized DNA, and inter-pret the diffraction pattern for structural information.
- Label the following statements about the world's largest gold bar as quantitative or qualitative observations. (This gold bar was worth approximately $10.25 million in 2013.) (a) The melting point of gold is 1064.2 °C. (b) The volume of the gold bar is 15,730 cm3. (c) Gold metal is a conductor of electricity. (d) The mass of the gold bar is 250 kg. (e) The gold bar is yellow and shiny
Problem 34
- Refer to Figure 1.2. What is developed when numerous observations support a hypothes
Problem 36
- What is the difference between a hypothesis and theory? (a) A hypothesis provides an explanation for a phenomenon, but a theory does not. (b) A theory provides an explanation for a phenomenon, but a hypothesis does not. (c) Both a theory and a hypothesis provide an explanation for a phenomenon, but a theory has been upheld by experi-mental observations
Problem 37
Problem 38a
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (a) Mass
Problem 38b
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (b) Length
Problem 38c
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (c) Temperature
Problem 38d
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (d) Volume
Problem 38e
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (e) Energy
Problem 38e
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (e) Energy
Problem 38f
What SI units are used for measuring the following quanti-ties? For derived units, express your answers in terms of the six fundamental units. (f) Density
- Complete the following equivalent expressions by filling in the blanks. (a) 1 km = ____ m (b) 1m = _____ km (c) 1 mmol = _____ mol (d) 1 mol = _____ mmol
Problem 40
- Bottles of wine sometimes carry the notation 'Volume = 75 cL. What does the unit cL mean?
Problem 42
- Which quantity in each of the following pairs is larger? (a) 5.63 * 106 cm or 6.02 * 101 km
Problem 43
- Which quantity in each of the following pairs is smaller? (c) 2.9 GA or 3.1 * 1015 mA
Problem 44
- How many microliters are in 1 L? In 20 mL?
Problem 46
Problem 47a
Carry out the following conversions. (a) 5 pm = _____ cm = _____ nm
Problem 47b
Carry out the following conversions. (b) 8.5 cm^3 = _____ m^3 = _____ mm^3
Problem 47c
Carry out the following conversions. (c) 65.2 mg = _____ = g = _____ pg