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Problem 125
The single proton that forms the nucleus of the hydrogen atom has a radius of approximately 1.0×10−13 cm. The hydrogen atom itself has a radius of approximately 52.9 pm. What fraction of the space within the atom is occupied by the nucleus?
Problem 126
A sample of gaseous neon atoms at atmospheric pressure and 0 °C contains 2.69×1022 atoms per liter. The atomic radius of neon is 69 pm. What fraction of the space do the atoms themselves occupy? What does this reveal about the separation between atoms in the gaseous phase?
Problem 127
The diameter of a hydrogen atom is 212 pm. Find the length in kilometers of a row of 6.02×1023 hydrogen atoms. The diameter of a ping pong ball is 4.0 cm. Find the length in kilometers of a row of 6.02×1023 ping pong balls.
Problem 128
The world's record in the 100-m dash is 9.69 s, and in the 100-yd dash it is 9.21 s. Find the speed in mi/hr of the runners who set these records. (Assume three significant figures for 100 m and 100 yd.)
Problem 129
The daily recommended intake of calcium for an average adult is 1,000 mg. There is 125 mg of calcium in 100 grams of milk. If a 150 g smoothie contains 75 grams of milk, how many grams of smoothie should an adult consume to meet the daily recommended intake?
Problem 130
Lead metal can be extracted from a mineral called galena, which contains 86.6% lead by mass. A particular ore contains 68.5% galena by mass. If the lead can be extracted with 92.5% efficiency, what mass of ore is required to make a lead sphere with a 5.00-cm radius?
Problem 131
A length of #8 copper wire (radius = 1.63 mm) has a mass of 24.0 kg and a resistance of 2.061 ohm per km (Ω / km). What is the overall resistance of the wire?
Problem 132
Rolls of aluminum foil are 304 mm wide and 0.016 mm thick. What maximum length of aluminum foil can be made from 1.10 kg of aluminum?
- Liquid nitrogen has a density of 0.808 g/mL and boils at 77 K. Researchers often purchase liquid nitrogen in insulated 175 L tanks. The liquid vaporizes quickly to gaseous nitrogen (which has a density of 1.15 g/L at room temperature and atmospheric pressure) when the liquid is removed from the tank. Suppose that all 175 L of liquid nitrogen in a tank accidentally vaporized in a lab that measured 10.00 m * 10.00 m * 2.50 m. What maximum fraction of the air in the room could be displaced by the gaseous nitrogen?
Problem 133
Problem 134
Mercury is often used in thermometers. The mercury sits in a bulb on the bottom of the thermometer and rises up a thin capillary as the temperature rises. Suppose a mercury thermometer contains 3.380 g of mercury and has a capillary that is 0.200 mm in diameter. How far does the mercury rise in the capillary when the temperature changes from 0.0 °C to 25.0 °C? The density of mercury at these temperatures is 13.596 g/cm3 and 13.534 g/cm3, respectively
- A force of 2.31 * 10^4 N is applied to a diver’s face mask that has an area of 125 cm^2. Find the pressure in atm on the face mask.
Problem 135
- Kinetic energy can be defined as (1/2)mv^2 or as (3/2)PV. Show that the derived SI units of each of these terms are those of energy. (Pressure is force/area and force is mass * acceleration.)
Problem 137
- A box contains a mixture of small copper spheres and small lead spheres. The total volume of both metals is measured by the displacement of water to be 427 cm³, and the total mass is 4.36 kg. What is the percentage of copper spheres?
Problem 142
- The diagram shown first represents solid carbon dioxide, also known as dry ice. Which of the other diagrams best represents the carbon dioxide after it has sublimed into a gas?
Problem 144
- A cube has an edge length of 7 cm. If it is divided up into 1 cm cubes, how many 1 cm cubes are there?
Problem 145
- Substance A has a density of 1.7 g/cm³. Substance B has a density of 1.7 kg/m³. Without doing any calculations, determine which substance is more dense.
Problem 146