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.
An essential part of the experimental design process is to select appropriate dependent and
independent variables.
True
False
10.00 g of Compound X with molecular formula C₂Hg are burned in a constant-pressure calorimeter containing 40.00 kg of water at 25 °C. The temperature of
the water is observed to rise by 2.604 °C. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.)
Calculate the standard heat of formation of Compound X at 25 °C.
Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
need help not sure what am doing wrong step by step please answer is 971A
During the lecture, we calculated the Debye length at physiological salt concentrations and temperature, i.e. at an ionic strength of 150 mM (i.e. 0.150 mol/l) and a temperature of T=310 K. We predicted that electrostatic interactions are effectively screened beyond distances of 8.1 Å in solutions with a physiological salt concentration.
What is the Debye length in a sample of distilled water with an ionic strength of 10.0 µM (i.e. 1.00 * 10-5 mol/l)? Assume room temperature, i.e. T= 298 K, and provide your answer as a numerical expression with 3 significant figures in Å (1 Å = 10-10 m).
Chapter 5 Solutions
Student Solutions Manual for Zumdahl/Zumdahl/DeCoste?s Chemistry, 10th Edition
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Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell