Concept explainers
(a)
Interpretation:
The ratio of the masses of
(b)
Interpretation:
The ratio of the masses of equal numbers of atoms of
(c)
Interpretation:
If the mass ratio of equal numbers of atoms of
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Chemistry: The Molecular Science
- The 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_forwardA materials engineer has filed for a patent for a new alloy to be used in golf club heads. The composition by mass ranges from 25 to 31% manganese, 6.3 to 7.8% aluminum, 0.65 to 0.85% carbon, and 5.5 to 9.0% chromium, with the remainder being iron. What are the maximum and minimum percentages of iron possible in this alloy? Use Figure 2.12 to snake a prediction about how the density of this alloy would compare with that of iron; justify your prediction.arrow_forwardTwo basic laws of chemistry are the law of conservation of mass and the law of constant composition. Which of these laws (if any) do the following statements illustrate? (a) Lavoisier found that when mercury(ll) oxide, HgO, decomposes, the total mass of mercury (Hg) and oxygen formed equals the mass of mercury(ll) oxide decomposed. (b) Analysis of the calcium carbonate found in the marble mined in Carrara, Italy, and in the stalactites of the Carlsbad Caverns in New Mexico gives the same value for the percentage of calcium in calcium carbonate. (c) Hydrogen occurs as a mixture of two isotopes, one of which is twice as heavy as the other.arrow_forward
- Which of these statements are qualitative? Which are quantitative? Explain your choice in each case. (a) Sodium is a silvery-white metal. (b) Aluminum melts at 660 C. (c) Carbon makes up about 23% of the human body by mass. (d) Pure carbon occurs in different forms: graphite, diamond, and fullerenes.arrow_forwardThe age of the universe is unknown, but some conclude from measuring Hubbles constant that the age is about 18 billion years old, which is about four times the age of Earth. If so, calculate the age of the universe in seconds. If you had a sample of carbon with the same number of carbon atoms as there have been seconds since the universe began, determine whether you could measure this sample on a laboratory balance that can detect masses as small as 0.1 mg.arrow_forward3.116 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_forward
- The 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_forwardhe vigorous reaction between aluminum and iodine gives the balanced equation: :math>2Al(s)+3I2(s)2AlI2(s). mg src=Images/HTML_99425-9-2QAP_image001.jpg alt="" align="top"/> at do the coefficients in this balanced chemical equation tell us about the proportions in which these substances react on a macroscopic (mole) basis?arrow_forwardA sample of cocaine, C17H21O4N, is diluted with sugar, C12H22O11. When a 1.00-mg sample of this mixture is burned, 1.00 mL of carbon dioxide (d=1.80g/L) is formed. What is the percentage of cocaine in this mixture?arrow_forward
- 2.95 Engineers who design bicycle frames are familiar with the densities of aluminium (2.699 g/cm3), steel (7.87 g/cm3), and titanium (4.507 g/cm3). How does this information compare with Figure 2.12, and what would it suggest for changes in this figure if more shades were used for the density colour-coding? (Iron is the principal component of steel)arrow_forwardTwo general chemistry students working together in the lab weigh out 0.832 g of CaCl2 2 H2O into a crucible. After heating the sample for a short time and allowing the crucible to cool, the students determine that the sample has a mass of 0.739 g. They then do a quick calculation. On the basis of this calculation, what should they do next? (a) Congratulate themselves on a job well done. (b) Assume the bottle of CaCl2 2 H2O was mislabeled; it actually contained something different. (c) Heat the crucible again, and then reweigh it.arrow_forward3.107 As computer processor speeds increase, it is necessary for engineers to increase the number of circuit elements packed into a given area. Individual circuit elements are often connected using very small copper “wires” deposited directly onto the surface of the chip. In some processors, these copper interconnects are about 22 nm wide. How many copper atoms would be in a 1-mm length of such an interconnect, assuming a square cross section? (The density of copper is 8.96 g/cm3.)arrow_forward
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