Sodium chloride and strontium chloride are both white solids. How could you distinguish one from the other?

Choose the expression that most logically completes each sentence. Tu as ____ des examens. a. as chaud b. as peur c. as raison

Determine the oxidation number of each element in each of the following compounds: (a) $\mathrm{HCN}$ (b) $\mathrm{OF}_2$ (c) $\mathrm{AsCl}_3$

Write balanced chemical equations for the reaction of the following acid anhydrides with water: (a) $\mathrm{SO}_3$ (b) $\mathrm{N}_2 \mathrm{O}_3$ (c) $\mathrm{Cl}_2 \mathrm{O}_7$ (d) $\mathrm{P}_4 \mathrm{O}_{10}$ (e) $\mathrm{NO}_2$

Nitrogen in the atmosphere exists as very stable diatomic molecules. Why does phosphorus form less stable $\mathrm{P}_4$ molecules instead of $\mathrm{P}_2$ molecules?

Carbon forms a number of allotropes, two of which are graphite and diamond. Silicon has a diamond structure. Why is there no allotrope of silicon with a graphite structure?

Indicate whether these statements are vrai or faux

Le cours de stylisme est à quatre heures vingt.

Select the person each statement describes.

II/Elle a cours de stylisme.

a. Sandrine

b. Amina

c. Astrid

d. Rachid

e. Stephane

Choose whether the statement is vrai or faux.

Le jeudi, Amina a cours de stylisme.

Suppose you discovered a diamond completely encased in a silicate rock. How would you chemically free the diamond without harming it?

A hydride of silicon prepared by the reaction of $\mathrm{Mg} 2 \mathrm{Si}$ with acid exerted a pressure of 306 torr at $26^{\circ} \mathrm{C}$ in a bulb with a volume of $57.0 \mathrm{~mL}$. If the mass of the hydride was $0.0861 \mathrm{~g}$, what is its molecular mass? What is the molecular formula for the hydride?

From the data given in Appendix I, determine the standard enthalpy change and the standard free energy change for each of the following reactions: (a) $\mathrm{BF}_3(\mathrm{~g})+3 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow \mathrm{B}(\mathrm{OH})_3(\mathrm{~s})+3 \mathrm{HF}(\mathrm{g})$ (b) $\mathrm{BCl}_3(\mathrm{~g})+3 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow \mathrm{B}(\mathrm{OH})_3(\mathrm{~s})+3 \mathrm{HCl}(\mathrm{g})$ (c) $\mathrm{B}_2 \mathrm{H}_6(\mathrm{~g})+6 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \longrightarrow 2 \mathrm{~B}(\mathrm{OH})_3(s)+6 \mathrm{H}_2(\mathrm{~g})$

Write a formula for each of the following compounds: (a) silicon dioxide (b) silicon tetraiodide (c) silane (d) silicon carbide (e) magnesium silicide

Predict the best choice in each of the following. You may wish to review the chapter on electronic structure for relevant examples. (a) the most metallic of the elements $\mathrm{Al}, \mathrm{Be}$, and $\mathrm{Ba}$ (b) the most covalent of the compounds $\mathrm{NaCl}, \mathrm{CaCl}_2$, and $\mathrm{BeCl}_2$ (c) the lowest first ionization energy among the elements $\mathrm{Rb}, \mathrm{K}$, and $\mathrm{Li}$ (d) the smallest among $\mathrm{Al} \mathrm{Al}^{+}$, and $\mathrm{Al}^{3+}$ (e) the largest among $\mathrm{Cs}^{+}, \mathrm{Ba}^{2+}$, and $\mathrm{Xe}$