1. Intro to General Chemistry

The two objects shown below have the same mass. Which has the largest density?

Calculate the volume in liters of a rectangular object with dimensions 13.0 cm * 11.0 cm * 12.0 cm. (a) 1720 L (b) 1.72 L (c) 14.3 L (d) 2.41 L

(a) Three spheres of equal size are composed of aluminum 1density = 2.70 g/cm32, s i lver 1density = 10.49 g/cm32, and nickel 1density = 8.90 g/cm32. List the spheres from lightest to heaviest.

(d) A cubic piece of metal measures 5.00 cm on each edge. If the metal is nickel, whose density is 8.90 g>cm3, what is the mass of the cube?

(c) A spherical ball of lead has a diameter of 5.0 cm. What is the mass of the sphere if lead has a density of 11.34 g>cm3? (The volume of a sphere is 14>32pr3, where r is the radius.)

How many 1-cm squares would it take to construct a square that is 1 m on each side?

A copper refinery produces a copper ingot weighing 70 kg. If the copper is drawn into wire whose diameter is 7.50 mm, how many meters of copper can be obtained from the ingot? The density of copper is 8.94 g>cm3. (Assume that the wire is a cylinder whose volume V = pr2h, where r is its radius and h is its height or length.)

The density of silver is 10.5 g/cm3. What is the mass (in kilo-grams) of a cube of silver that measures 0.62 m on each side?

What is the density of lead in g/cm3 if a rectangular bar mea-suring 0.50 cm in height, 1.55 cm in width, and 25.00 cm in length has a mass of 220.9 g?

What is the density of lithium metal in g/cm3 if a cylindrical wire with a diameter of 2.40 mm and a length of 15.0 cm has a mass of 0.3624 g?

(b) Using the mass of the proton from Table 2.1 and assuming its diameter is 1.0 * 10-15 m, calculate the density of a proton in g>cm3.

Very small semiconductor crystals, composed of approximately 1000 to 10,000 atoms, are called quantum dots. Quantum dots made of the semiconductor CdSe are now being used in electronic reader and tablet displays because they emit light efficiently and in multiple colors, depending on dot size. The density of CdSe is 5.82 g/cm3. (c) What is the mass of one 6.5-nm CdSe quantum dot?

Very small semiconductor crystals, composed of approximately 1000 to 10,000 atoms, are called quantum dots. Quantum dots made of the semiconductor CdSe are now being used in electronic reader and tablet displays because they emit light efficiently and in multiple colors, depending on dot size. The density of CdSe is 5.82 g/cm3. (a) What is the mass of one 2.5-nm CdSe quantum dot?

U.S. 1-cent coin (a penny) has a diameter of 19 mm and a thickness of 1.5 mm. Assume the coin is made of pure copper, whose density and approximate market price are 8.9 g/cm3 and $2.40 per pound, respectively. Calculate the value of the copper in the coin, assuming its thickness is uniform.

Neutron stars are composed of solid nuclear matter, primarily neutrons. Assume the radius of a neutron is approximately 1.0 * 10 - 13 cm. Calculate the density of a neutron. [Hint: For a sphere V = (4>3)pr3.] Assuming that a neutron star has the same density as a neutron, calculate the mass (in kg) of a small piece of a neutron star the size of a spherical pebble with a radius of 0.10 mm.

Carbon-12 contains six protons and six neutrons. The radius of the nucleus is approximately 2.7 fm (femtometers) and the radius of the atom is approximately 70 pm (picometers). What percentage of the carbon atom's volume is occupied by the nucleus? (Assume two significant figures.)

Carbon-12 contains six protons and six neutrons. The radius of the nucleus is approximately 2.7 fm (femtometers) and the radius of the atom is approximately 70 pm (picometers). Calculate the volume of the nucleus and the volume of the atom.

(c) Using the volume of a silver atom and the formula for the volume of a sphere, calculate the radius in angstroms of a silver atom.

Lignum vitae is a hard, durable, and extremely dense wood used to make ship bearings. A sphere of this wood with a diameter of 7.60 cm has a mass of 313 g. (a) What is the density of the lignum vitae sphere? (b) Will the sphere float or sink in water? (c) Will the sphere float or sink in chloroform? (The density of chloroform is 1.48 g/mL.)

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is approximately 300 mg HCN per kilogram of air when inhaled. (a) Calculate the amount of HCN that gives the lethal dose in a small laboratory room measuring 3.5 * 4.5 * 2.5 m. The density of air at 26 C is 0.00118 g>cm3.

A thief uses a can of sand to replace a solid gold cylinder that sits on a weight-sensitive, alarmed pedestal. The can of sand and the gold cylinder have exactly the same dimensions (length = 22 and radius = 3.8 cm). a. Calculate the mass of each cylinder (ignore the mass of the can itself). (density of gold = 19.3 g>cm3, density of sand = 3.00 g>cm3) b. Does the thief set off the alarm? Explain.

Imagine that you place a cork measuring 1.30 cm * 5.50 cm * 3.00 cm in water and that on top of the cork you place a small cube of lead measuring 1.15 cm on each edge. The density of cork is 0.235 g/cm3, and the density of lead is 11.35 g/cm3. Will the combination of cork plus lead float or sink?

What is the edge length (in cm) of a titanium cube that contains 2.55 * 1024 titanium atoms? The density of titanium is 4.50 g/cm3.

The proton has a radius of approximately 1.0 * 10 - 13 cm and a mass of 1.7 * 10 - 24 g. Determine the density of a proton for a sphere V = (4>3) pr 3.

Brass is a copper–zinc alloy. What is the mass in grams of a brass cylinder having a length of 1.62 in. and a diameter of 0.514 in. if the composition of the brass is 67.0% copper and 33.0% zinc by mass? The density of copper is 8.92 g/cm3, and the density of zinc is 7.14 g/cm3. Assume that the den-sity of the brass varies linearly with composition.

A steel cylinder has a length of 2.16 in, a radius of 0.22 in, and a mass of 41 g. What is the density of the steel in g>cm3?

A solid aluminum sphere has a mass of 85 g. Use the density of aluminum to find the radius of the sphere in inches.

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?

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?

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?

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

An 8.894 g block of aluminum was pressed into a thin square of foil with 36.5 cm edge lengths. (a) If the density of Al is 2.699 g>cm3, how thick is the foil in centimeters?