One of the chemical controversies of the nineteenth century concerned the element beryllium (Be). Berzelius originally claimed that beryllium was a trivalent element (forming Be 3+ ions) and that it gave an oxide with the formula Be 2 O 3 . This resulted in a calculated atomic mass of 13.5 for beryllium. In formulating his periodic table, Mendeleev proposed that beryllium was divalent (forming Be 2+ ions) and that it gave an oxide with the formula Be 2 O 3 . This assumption gives an atomic mass of 9.0. In 1894, A. Combes ( Comptes Rendus 1894, p. 1221) reacted beryllium with the anion C 5 H 7 O 2 − and measured the density of the gaseous product. Combes’s data for two different experiments are as follows: I II Mass 0.2022 g 0.2224 g Volume 22.6 cm 3 26.0 cm 3 Temperature 13°C 17°C Pressure 765.2 mm Hg 764.6 mm If beryllium is a divalent metal, the molecular formula of the product will be Be(C 5 H 7 O 2 ) 2 ; if it is trivalent, the formula will be Be(C 5 H 7 O 2 ) 3 . Show how Combes’s data help to confirm that beryllium is a divalent metal.
One of the chemical controversies of the nineteenth century concerned the element beryllium (Be). Berzelius originally claimed that beryllium was a trivalent element (forming Be 3+ ions) and that it gave an oxide with the formula Be 2 O 3 . This resulted in a calculated atomic mass of 13.5 for beryllium. In formulating his periodic table, Mendeleev proposed that beryllium was divalent (forming Be 2+ ions) and that it gave an oxide with the formula Be 2 O 3 . This assumption gives an atomic mass of 9.0. In 1894, A. Combes ( Comptes Rendus 1894, p. 1221) reacted beryllium with the anion C 5 H 7 O 2 − and measured the density of the gaseous product. Combes’s data for two different experiments are as follows: I II Mass 0.2022 g 0.2224 g Volume 22.6 cm 3 26.0 cm 3 Temperature 13°C 17°C Pressure 765.2 mm Hg 764.6 mm If beryllium is a divalent metal, the molecular formula of the product will be Be(C 5 H 7 O 2 ) 2 ; if it is trivalent, the formula will be Be(C 5 H 7 O 2 ) 3 . Show how Combes’s data help to confirm that beryllium is a divalent metal.
Solution Summary: The author explains that beryllium is a divalent element with an atomic weight of 9.0u.
One of the chemical controversies of the nineteenth century concerned the element beryllium (Be). Berzelius originally claimed that beryllium was a trivalent element (forming Be3+ ions) and that it gave an oxide with the formula Be2O3. This resulted in a calculated atomic mass of 13.5 for beryllium. In formulating his periodic table, Mendeleev proposed that beryllium was divalent (forming Be2+ ions) and that it gave an oxide with the formula Be2O3. This assumption gives an atomic mass of 9.0. In 1894, A. Combes (Comptes Rendus 1894, p. 1221) reacted beryllium with the anion C5H7O2−and measured the density of the gaseous product. Combes’s data for two different experiments are as follows:
I
II
Mass
0.2022 g
0.2224 g
Volume
22.6 cm3
26.0 cm3
Temperature
13°C
17°C
Pressure
765.2 mm Hg
764.6 mm
If beryllium is a divalent metal, the molecular formula of the product will be Be(C5H7O2)2; if it is trivalent, the formula will be Be(C5H7O2)3. Show how Combes’s data help to confirm that beryllium is a divalent metal.
Study of body parts and their functions. In this combined field of study, anatomy refers to studying the body structure of organisms, whereas physiology refers to their function.
What volume (in mL) of 3.20 M HNO3(aq)
needs to be added to excess Na,CO3(s) to
generate 4.85 L CO2(g) at standard
temperature and pressure (STP)?
Provide your answer in decimal notation
rounded to the appropriate number of
significant figures.
Effervescent tablets contain both citric acid (C6H8O7) and sodium bicarbonate
(NaHCO3) and release carbon dioxide gas when dissolved in water as well as
forming trisodium citrate (Na3C6H5O7) and water. A typical effervescent tablet
contains 1.00 g of citric acid and 1.92 g sodium bicarbonate.
(a) Assuming that carbon dioxide acts as an ideal gas, determine the work
done due to the evolution of carbon dioxide by the dissolution of one
effervescent tablet in water at 25.0 °C and atmospheric pressure (1 atm
i.e. 101325 Pa).
Silicon tetrachloride (SICI4 ) can be prepared by heating Si in chlorine gas:
Si(s) + 2C12(g) -> SICIĄ(1)
In one reaction, 0.507 mole of SICI4 is produced. What mass (grams) of molecular chlorine were used in the reaction? Choose the
nearest answer. MW SICI4 = 169.9 g/mol; MW CI = 35.453 g/mol
A) 63 grams
B) 36 grams
72 grams
27 grams
Chapter 5 Solutions
Study Guide for Zumdahl/Zumdahl/DeCoste’s Chemistry, 10th Edition
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