Which of the following statements is(are) true? Explain. Oxidation and reduction accompany all chemical reactions.

What type of molecule results when many smaller units are joined in addition reactions?

Draw the two possible dipeptides formed by condensation reactions between histidine and aspartic acid.

Rank the aryl halides in each group in order of increasing reactivity in nucleophilic aromatic substitution by an addition–elimination mechanism. a. chlorobenzene, p-fluoronitrobenzene, m-fluoronitrobenzene. b. 1-fluoro-2,4-dinitrobenzene, 1-fluoro-3,5-dinitrobenzene, 1-fluoro-3,4-dinitrobenzene. c. 1-fluoro-2,4-dinitrobenzene, 4-chloro-3-nitrotoluene, 4-fluoro-3-nitrotoluene.

Which reactions in the citric acid cycle form a product with a new asymmetric center?

Determine the magnitudes of the pin reactions at A, B, and C caused by the weight of the uniform 6000-lb beam.

Determine whether or not strangeness is conserved in the following decays and reactions.

$$\Xi^{0} \rightarrow \mathrm{p}+\pi^{-}$$

Which of the following statements about chemical equations is (are) true? a. When balancing a chemical equation, you can never change the coefficient in front of any chemical formula. b. The coefficients in a balanced chemical equation refer to the number of grams of reactants and products. c. In a chemical equation, the reactants are on the right and the products are on the left. d. When balancing a chemical equation, you can never change the subscripts of any chemical formula. e. In chemical reactions, matter is neither created nor destroyed, so a chemical equation must have the same number of atoms on both sides of the equation.

Select all the true statements regarding chemical equilibrium: -The concentrations of reactants and products remain constant. -The concentrations of reactants and products are equal. -Reactants are still being converted to products (and vice versa). -The rates of the forward and reverse reactions are equal.

Which are the catalysts of reactions in living things? a. enzymes b. lipids c. carbohydrates d. substrates

How does Mr. DePalma's reaction to news of the assassination differ from the students' reactions?

Consider the bond energies of three iodine halides:

$$\begin{matrix} \text{Bond} & \text{Bond Energy}\\ \text{Br - Cl} & \text{218 kJ/mol}\\ \text{Br - Br} & \text{193kJ/mol}\\ \text{I-Br} & \text{175kJ/mol}\\ \end{matrix}$$

How might you use valence bond theory to help explain this trend?

Sulfur forms oxides, oxoanions, and halides. What is the hybridization of the central $\mathrm{S}$ in $\mathrm{SO}_2, \mathrm{SO}_3, \mathrm{SO}_3{ }^{2-}, \mathrm{SCl}_4, \mathrm{SCl}_6$, and $\mathrm{S}_2 \mathrm{Cl}_2$ (atom sequence $\mathrm{Cl}-\mathrm{S}-\mathrm{S}-\mathrm{Cl}$ )?

Which statement about enthalpy is true?

• The sign of AH is always negative in exothermic reactions
• Heat is given off to the surroundings in endothermic reactions
• Some substances have a negative specific heat capacity
• Specific heat capacity is the same for all liquids