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Questions in chemistry

[Done] To produce foamed plastics like Styrofoam, as a propellant in spray cans, and as a refrigerant in air conditioners and refrigerators: A. Ozone gas has been used B. Chlorofluorocarbons have been used C. Carbon dioxide has been used D. Hydrofluorocarbons have been used

[Done] Which process is a chemical change? A. burning a match B. boiling water C. melting ice D. breaking glass

[Done] A student takes a measured volume of 3.00 M HCl to prepare a 50.0 mL sample of 1.80 M HCl. What volume of 3.00 M HCl did the student use to make the sample? Use [tex]M_i V_i=M_f V_f[/tex]. A. 3.70 mL B. 16.7 mL C. 30.0 mL D. 83.3 mL

[Done] Identify the base in this acid-base reaction: [tex]2 HC_2 H_3 O_2+Mg(OH)_2 \rightarrow Mg\left(C_2 H_3 O_2\right)_2+2 H_2 O[/tex] A. [tex]HC _2 H _3 O _2[/tex] B. [tex]Mg ( OH )_2[/tex] C. [tex]Mg \left( C _2 H _3 O _2\right)_2[/tex] D. [tex]H _2 O[/tex]

[Done] Propane burns in air to produce carbon dioxide and water. What is this type of chemical reaction called? A. synthesis B. combustion C. decomposition D. single replacement

[Done] Which of the following is the most suitable requirement for the dehydration of ethanol to form an ether? A. Sodium hydroxide at 443K B. Sulphuric acid at 443K C. Sulphuric acid at 413K D. Sodium hydroxide at 413K

[Done] Identify the base in this acid-base reaction: $NaOH + HCl \rightarrow NaCl + H _2 O$ A. NaOH B. HCl C. NaCl D. $H _2 O$

[Done] Maltose $+ H _2 O \longleftrightarrow 2$ Glucose Calculate the equilibrium constant under standard transformed conditions ( $K_{e q}^{\prime}$ ) knowing that for this reaction $\Delta G^{* \prime}=-15.5 kJ . mol ^{-1}$. Make sure to use the correct unit for $K_{e q}^{\prime}$. A. 0.527 mol B. $0.527 mol^{-1} L^{-1}$ C. $526.724 L.mol^{-1}$ D. 526.724 (unitless) E. $526.724 mol^{-1} L^{-1}$

[Done] Select the best answer for the question. 17. On Earth, where is hydrogen not found? A. Water B. Natural gas well C. Mine D. Atmosphere

[Done] A compound is used as a food additive. The compound has a molar mass of 176.124 grams/mole. A 692.5-gram sample undergoes decomposition, producing 283.4 grams of carbon, 31.7 grams of hydrogen, and 377.4 grams of oxygen. What is the molecular formula of the compound? A. $C_3H_4O_3$ B. $C_4H_6O_4$ C. $C_6H_6O_6$ D. $C_6H_8O_6$