Concept explainers
you can use the concepts in this chapter to obtain an estimate of the number of atoms in the universe. These steps will guide you through this calculation.
a. Begin by calculating the number of atoms in the sun. Assume that the sun is pure hydrogen with a density of
b. The sun is an average-sized star, and stars are believed to compose most of the mass of the visible universe (planets are so small they can be ignored), so we can estimate the number of atoms in a galaxy by assuming that every star in the galaxy has the same number of atoms as our sun. The Milky Way galaxy is believed to contain
c. Astronomers estimate that the universe contains approximately
Our sun is one of the 100 billion stars in the Milky Way galaxy. The universe is estimated to contain about 100 billion galaxies.
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Chapter 6 Solutions
Introductory Chemistry Essentials Plus MasteringChemistry with eText -- Access Card Package (5th Edition)
- Consider the following data for three binary compounds of hydrogen and nitrogen: %H (by Mass) %N (by Mass) I 17.75 82.25 II 12.58 87.42 III 2.34 97.66 When 1.00 L of each gaseous compound is decomposed to its elements, the following volumes of H2(g) and N2(g) are obtained: H2(L) N2(L) I 1.50 0.50 II 2.00 1.00 III 0.50 1.50 Use these data to determine the molecular formulas of compounds I, II, and III and to determine the relative values for the atomic masses of hydrogen and nitrogen.arrow_forwardA cube of sodium has length 1.25 in. How many atoms are in that cube? (Note: dNa=0.968 g/cm3.)arrow_forwardReference Section 5-2 to find the atomic masses of 12C and 13C, the relative abundance of 12C and 13C in natural carbon, and the average mass (in u) of a carbon atom. If you had a sample of natural carbon containing exactly 10,000 atoms, determine the number of 12C and 13C atoms present. What would be the average mass (in u) and the total mass (in u) of the carbon atoms in this 10,000-atom sample? If you had a sample of natural carbon containing 6.0221 1023 atoms, determine the number of 12C and 13C atoms present What would be the average mass (in u) and the total mass (in u) of this 6.0221 1023 atom sample? Given that 1 g = 6.0221 1023 u, what is the total mass of I mole of natural carbon in units of grams?arrow_forward
- 3.116 The simplest approximate chemical formula for the human body could be written as C728H4850O1970N104Ca24P16K4S4Na3Cl2Mg. Based on this formula, describe how you would rank by mass the ten most abundant elements in the human body.arrow_forwardThe mass spectrum of CH3Cl is illustrated here. You know that carbon has two stable isotopes, and 13C with relative abundances of 98.9% and 1.1%, respectively, and chlorine has two isotopes, 35a and 37CI with abundances of 75.77% and 24.23%, respectively. (a) What molecular species gives rise to the lines at m/Z of 50 and 52? Why is the line at 52 about 1/3 the height of the line at 50? (b) What species might be responsible for the line at m/Z = 51?arrow_forwardThe mass spectrum of bromine (Br2) consists of three peaks with the following characteristics: Mass (u) Relative Size 157.84 0.2534 159.84 0.5000 161.84 0.2466 How do you interpret these data?arrow_forward
- Assume silicon has three major isotopes in nature as shown in the table below. Fill in the missing information. Isotope Mass (u) Abundance 28Si 27.98 _____ 29Si ____ 4.70% 30Si 29.97 3.09%arrow_forwardThe element bromine is Br2, so the mass of a Br2 molecule is the sum of the mass of its two atoms. Bromine has two isotopes. The mass spectrum of Br2 produces three peaks with relative masses of 157.836, 159.834, and 161.832, and relative heights of 6.337, 12.499. and 6.164, respectively. (a) What isotopes of bromine are present in each of the three peaks? (b) What is the mass of each bromine isotope? (c) What is the average atomic mass of bromine? (d) What is the abundance of each of the two bromine isotopes?arrow_forwardThere are 1.699 1022 atoms in 1.000 g of chlorine. Assume that chlorine atoms are spheres of radius 0.99 and that they are lined up side by side in a 0.5-g sample. How many miles in length is the line of chlorine atoms in the sample?arrow_forward
- Using the average atomic masses given inside the front cover of this book, calculate the number of atoms present in each of the following samples. l type='a'> 1.50 g of silver, Ag 0.0015 moIe of copper, Cu 0.0015 g of copper, Cu 2.00 kg of magnesium, Mg 2.34 oz of calcium, Ca 2.34 g of calcium, Ca 2.34 moles of calcium, Caarrow_forwardAn element X bas five major isotopes, which are listed below along with their abundances. What is the element? Isotope Percent Natural Abundance Mass (u) 46x 8.00% 45.95232 47x 7.30% 46.951764 48x 73.80% 47.947947 49x 5.50% 48.947841 50x 5.40% 49.944792arrow_forward
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