Solved: What coefficients must be placed in the following

Explain how table salt has emergent properties.

Is a trace element an essential element? Explain

Iron (Fe) is a trace element required for the proper functioning of hemoglobin, the molecule that carries oxygen in red blood cells. What might be the effects of an iron deficiency?

Alithium atom has 3 protons and 4 neutrons. What is its atomic mass in daltons?

A nitrogen atom has 7 protons, and the most common isotope of nitrogen has 7 neutrons. A radioactive isotope of nitrogen has 8 neutrons. Write the atomic number and mass number ofthis radioactive nitrogen as a chemical symbol with a subscript and superscript

How many electrons does fluorine have? How many electron shells? Name the orbitals that are occupied. How many electrons are needed to fill the valence shell?

In Figure 2.9, if two or more elements are in the same row, what do they have in common? If two or more elements are in the same column, what do they have in common?

Why does the following structure fail to make sense chemically? H-C~C-H

Explain what holds together the atoms in a crystal of magnesium chloride (Mg02)

If you were a pharmaceutical researcher, why would you want to learn the three-dimensional shapes of naturally occurring signaling molecules? For suggested answers. see Appendix A

Refer to the reaction between hydrogen and oxygen that forms water, shown with ball-and-stick models on page 42. Draw the Lewis dot structures representing this reaction.

Which types of chemical reactions occur faster at equilibrium, the formation of products from reactants, or reactants from products?

Write an equation that uses the products of photosynthesis as reactants and uses the reactants as products. Add energy as another product. This new equation describes a process that occurs in your cells. Describe this equation in words. How does this equation relate to breathing?

In the term trace clement, the modifier trace means a. the element is required in very small amounts. b. the element can be used as a label to trace atoms through an organism's metabolism. c. the element is very rare on Earth. d. the element enhances health but is not essential for the organism's long-term surviV'dl. e. the element passes rapidly through the organism.

. Compared with 31 P, the radioactive isotope 32p has a. a different atomic number. d. one more electron. b. one more neutron, e. a different charge.

Atoms can be represented by simply listing the number of protons, neutrons, and electrons-for example, 2p+; 2no; 2efor helium, Which one ofthe following lists represents the 180 isotope of oxygen? a.6p+;8no;6eb. 8p+; lOne; 8ec.9p+;9no;ge d.7p+;2no;gee. IOp+;8no;ge

The atomic number ofsulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula ofthe compound: a. H$ b. HS2 C. H2S d. H3S:l e. H4$

The reactivity of an atom arises from a. the average distance of the outermost electron shell from the nucleus. b. the existence of unpaired electrons in the valence shell. c. the sum ofthe potential energies of all the electron shells. d. the potential energy of the valence shell. e. the energy difference between the sand p orbitals

\Vhich statement is true of all atoms that are anions? a. The atom has more electrons than protons. b. The atom has more protons than electrons. c. The atom has fewer protons than does a neutral atom of the same element. d. The atom has more neutrons than protons. e. The net charge is 1-.

What coefficients must be placed in the following blanks so that all atoms are accounted for in the products?Ct;H120 6 ------+ __C2H60 +__C02a. 1; 2 b. 2; 2 c. 1; 3 d. 1; 1 e. 3; I

\Vhich ofthe following statements correctly describes any chemical reaction that has reached equilibrium? a. The concentrations of products and reactants are equal. b. The rates ofthe forward and reverse reactions are equal, c. Both forward and reverse reactions have halted. d. The reaction is now irreversible. e. No reactants remain.

Dmw Lewis structures for each hypothetical molecule shown below, using the correct number of valence electrons for each atom. Determine which molecule makes sense because each atom has a complete valence shell and each bond has the correct number of electrons. Explain what makes the other molecules nonsensical, considering the number of bonds each type of atom can make.

The percentages of naturally occurring elements making up the human body (see Table 2.1) are similar to the percentages of these elements found in other organisms. How could you account for this similarity among organisms?

Female silkworm moths (Bombyx man) attract males by emitting chemical signals that spread through the air. A male hundreds of meters away can detect these molecules and fly to\'fdrd their source. The sensory organs responsible for this behavior are the comblike antennae visible in the photogmph here. Each filament of an antenna is equipped with thousands of receptor cells that detect the sex attmctant. Based on what you learned in this chapter, propose a hypothesis to account for the ability ofthe male moth to detect a specific molecule in the presence ofmany other molecules in the air. What predictions does your hypothesis make? Design an experiment to test one ofthese predictions.

While waiting at an airport, Neil Campbell once overheard this claim: "It's paranoid and ignorant to worry about industry or agriculture contaminating the environment with their chemical wastes. After all, this stuffis just made ofthe same atoms that were already present in our environment~How would you counter this argument?