How many helium atoms are there in a helium blimp containing 587 kg of helium?

Calculate the average mass, in grams, of one platinum atom.

Using scanning tunneling microscopy, scientists at IBM wrote the initials of their company with 35 individual xenon atoms (as shown below). Calculate the total mass of these letters in grams.

A 7.83 g sample of HCN contains 0.290 g of H and 4.06 g of N. Find the mass of carbon in a sample of HCN with a mass of 3.37 g.

The ratio of sulfur to oxygen by mass in SO₂ is 1.0:1.0. a. Find the ratio of sulfur to oxygen by mass in SO₃. b. Find the ratio of sulfur to oxygen by mass in S₂O.

The ratio of oxygen to carbon by mass in carbon monoxide is 1.33:1.00. Find the formula of an oxide of carbon in which the ratio by mass of oxygen to carbon is 2.00:1.00.

The ratio of the mass of a nitrogen atom to the mass of an atom of ¹²C is 7:6, and the ratio of the mass of nitrogen to oxygen in N₂O is 7:4. Find the mass of 1 mol of oxygen atoms.

An a particle, 4He2 + , has a mass of 4.00151 amu. Find the value of its charge-to-mass ratio in C/kg.

Naturally occurring iodine has an atomic mass of 126.9045 amu. A 12.3849 g sample of iodine is accidentally contaminated with an additional 1.00070 g of ¹²⁹I, a synthetic radioisotope of iodine used in the treatment of certain diseases of the thyroid gland. The mass of ¹²⁹I is 128.9050 amu. Find the apparent 'atomic mass' of the contaminated iodine.

Use the mass spectrum of lead to estimate the atomic mass of lead. Estimate the mass and percent intensity values from the graph to three significant figures.

Use the mass spectrum of mercury to estimate the atomic mass of mercury. Estimate the masses and percent intensity values from the graph to three significant figures.

Nuclei with the same number of neutrons but different mass numbers are called isotones. Write the symbols of four isotones of ²³⁶Th.

Fill in the blanks to complete the table. Symbol Z A Number of p_x001E_ Number of e_x001D_ Number of n Charge Si 14 ____ ____ 14 14 ____ S2- ____ 32 ____ ____ ____ 2- Cu2+ ____ ____ ____ ____ 34 2+ ____ 15 ____ ____ 15 16 ____

Fill in the blanks to complete the table. Symbol Z A Number of p Number of e− Number of n Charge ______ 8 ______ ______ ______ 8 2- Ca2 + 20 ______ ______ ______ 20 ______ Mg2 + ______ 25 ______ ______ 13 2+ N3 - ______ 14 ______ 10 ______ ______

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)πr³.] 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). Calculate the volume of the nucleus and the volume of the atom.

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.)

A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in km)? [For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth.]

Consider the stack of pennies in the previous problem. How much money (in dollars) would this represent? If this money were equally distributed among the world's population of 7.0 billion people, how much would each person receive? Would each person be a millionaire? A billionaire? A trillionaire?

The mass of an average blueberry is 0.75 g and the mass of an automobile is 2.0×10³ kg. Find the number of automobiles whose total mass is the same as 1.0 mol of blueberries.

A pure titanium cube has an edge length of 2.78 in. How many titanium atoms does it contain? Titanium has a density of 4.50 g/cm³.

A pure copper sphere has a radius of 0.935 in. How many copper atoms does it contain? [The volume of a sphere is (4/3)πr³ and the density of copper is 8.96 g/cm³.]

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.

Boron has only two naturally occurring isotopes. The mass of boron-10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu. Calculate the relative abundances of the two isotopes.

Lithium has only two naturally occurring isotopes. The mass of lithium-6 is 6.01512 amu and the mass of lithium-7 is 7.01601 amu. Calculate the relative abundances of the two isotopes.

Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 g/cm³. A fitting composed of common brass has a total volume of 112.5 cm³. How many atoms (copper and zinc) does the fitting contain?

A 67.2 g sample of a gold and palladium alloy contains 2.49×10²³ atoms. What is the composition (by mass) of the alloy?

Naturally occurring chlorine is composed of two isotopes: 75.76% Cl-35 (mass 34.9688 amu) and 24.24% Cl-37 (mass 36.9659 amu). Naturally occurring oxygen is composed of three isotopes: 99.757% O-16 (mass 15.9949 amu), 0.038% O-17 (mass 16.9991 amu), and 0.205% O-18 (mass 17.9991 amu). The compound dichlorine monoxide is composed of two chlorine atoms and one oxygen atom bonded together to form the Cl₂O molecule. How many Cl₂O molecules of different masses naturally exist? Give the masses of the three most abundant Cl₂O molecules.

Silver is composed of two naturally occurring isotopes: Ag-107 (51.839%) and Ag-109. The ratio of the masses of the two isotopes is 1.0187. What is the mass of Ag-107?