4: Compounds- Safer Materials for a Safer World
- Page ID
- 284483
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)“The millions of known chemical compounds vary tremendously in their properties. For example, some are so unstable that just touching them with a steel spatula will cause them to explode spontaneously. Others are so stable and persistent that they last practically forever in the environment”
- 4.1: Chemical Bonds and Compound Formation
- This page discusses chemical compounds formed from elements via covalent or ionic bonds, highlighting bond strength and environmental impact. It emphasizes stable compounds like chlorofluorocarbons, which harm the ozone layer, and promotes green chemistry focusing on eco-friendly alternatives. Key traits of green compounds include renewability, low toxicity, non-flammability, and biodegradability, with sodium stearate as an example of a sustainable, biodegradable soap byproduct.
- 4.2: Electrons Involved in Chemical Bonds and Octets of Electrons
- This page explores valence electrons and the octet rule, emphasizing that atoms form bonds to achieve stable outer electron shells. It uses noble gases as models of stability and illustrates how elements like hydrogen and carbon obtain this stability through various bonding methods. Examples include covalent bonds (H2, N2, Cl2) and ionic bonds (NaCl), with a focus on how these principles apply to the formation of chemical compounds, including methane (CH4).
- 4.3: Sodium Chloride and Ionic Bonds
- This page discusses ionic compounds formed from cations and anions, highlighting their stability from strong ionic attractions and lattice energy. Examples include sodium chloride and its industrial counterparts. It also covers ionic liquids, which consist of large organic ions and remain liquid at low temperatures.
- 4.4: Covalent Bonds in H2 and Other Molecules
- This page explains Lewis symbols and their role in illustrating electron loss and gain in atoms, forming cations and anions. Atoms on the left side of the periodic table usually lose electrons, while those on the right gain them. Forming cations with charges over +2 or anions under -2 is difficult, leading middle-table atoms to share electrons through covalent bonds. This sharing helps reduce repulsion between positive nuclei, as demonstrated in the hydrogen molecule (H2).
- 4.5: Covalent Bonds in Compounds
- This page explores covalent bonds among lighter elements, emphasizing the octet rule and outer shell electron arrangements similar to noble gases. It illustrates hydrogen's bond formation in H2, achieving stability with 2 electrons, while other elements pursue 8 electrons. Covalent bonds are categorized by the degree of electron sharing (single, double, triple) and are depicted in molecular structures.
- 4.6: Covalent Bonds and Green Chemistry
- This page discusses the role of covalent bonds in green chemistry, highlighting how they affect energy needs, environmental impact, reactivity, and toxicity. Strong bonds, such as in N2, require harsh conditions for creation, while stable bonds can harm the environment, like those in dichlorodifluoromethane. Weak bonds lead to harmful reactions, exemplified by nitrogen dioxide causing smog.
- 4.7: Predicting Formulas of Covalently Bound Compounds
- This page explains how Lewis symbols and the octet rule help predict molecular formulas, exemplified by CO2 and H2O2. It highlights hydrogen's simple bonding and cases like NO where resonance structures are needed. The text discusses water's polar nature due to unequal electron sharing and introduces coordinate covalent bonds through NH3 and H3O+. Additionally, it emphasizes hydrogen peroxide's function as both a strong oxidant and a safer bleaching agent.
- 4.8: Chemical Formulas, the Mole, and Percentage Composition
- This page explains chemical formulas, detailing their role in conveying information about compounds, such as elements, atom counts, molar mass, and percentage composition. It introduces the mole concept, defined by Avogadro's number (6.02×10^23), and describes how to calculate molar mass using atomic or molecular masses. An example involving ammonium sulfate illustrates the calculation of percentage composition of its components.
- 4.9: What Are Chemical Compounds Called?
- This page explains naming conventions for inorganic chemical compounds, emphasizing binary molecular compounds that use prefixes for atom quantities, such as dinitrogen pentoxide (N2O5). It distinguishes ionic compounds, which do not utilize prefixes, illustrated by formulas like sodium sulfate (Na2SO4). Additionally, it touches on common names and outlines the naming process for compounds with multiple ions using prefixes as needed.
- 4.10: Acids, Bases and Salts
- This page explains the classification of inorganic compounds into acids, bases, and salts. Acids produce H+ ions, with strong examples like sulfuric acid fully dissociating and weak acids like carbon dioxide producing minimal H+. Bases contain or produce hydroxide ions (OH-), such as sodium hydroxide. Salts result from acid-base reactions and contain different cations and anions. Knowledge of their properties and naming is essential for applications in industry and environmental chemistry.
- Questions and Problems
- This page explores various chemistry-related questions to encourage inquiry into topics such as chemical compounds, green chemistry, bonding, and molecular structure. It addresses differences between elements and compounds, characteristics of green chemicals, properties of ionic and covalent bonds, and the octet rule. Additionally, it examines the implications of these concepts in chemical reactions and sustainable practices.