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A liquid fuel was burned in a spirit burner and the heat released was used to warm water in a metal calorimeter, as shown. Q = mcΔT What is the standard enthalpy change of combustion, ΔHcombustion⊖, of the fuel according to the…
Which row correctly describes an endothermic reaction? A. The temperature of the surroundings rises and the products are more stable than the reactants. B. The temperature of the surroundings falls and the products are more stable than the reactants. C. The…
Sulfur has different oxidation states in hydrogen sulfide, H2S, and in sulfurous acid, H2SO3. Which pair of values is correct? A. H2S: +2; H2SO3: +4 B. H2S: −2; H2SO3: +6 C. H2S: −2; H2SO3: +4 D.…
What is the coefficient of oxygen when the equation for the complete combustion of butan-1-ol is balanced using the smallest whole numbers? The unbalanced equation is C4H9OH + O2 → CO2 + H2O. A. 4 B. 6 C. 7 D. 13
When 0.601 g of propan-1-ol is burned, the heat released raises the temperature of 250 cm3 of water by 8.00 K. What is the enthalpy of combustion of propan-1-ol, in kJ mol−1, calculated from these results? Specific heat capacity of…
A chemical reaction occurs in a mixture that starts at the same temperature as its surroundings. Immediately after the reaction, the mixture is warmer than before. Which row correctly describes the energy changes in the system and in the surroundings as the…
What are the limiting reactant and the theoretical yield of hydrogen when 0.30 mol of aluminium reacts with 0.60 mol of hydrochloric acid? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) In each option the limiting reactant is given first and the theoretical…
Which route to chloroethane has an atom economy of 100 %? A. C2H5OH + PCl5 → C2H5Cl + POCl3 + HCl B. C2H6 + Cl2 → C2H5Cl + HCl C. C2H5OH + HCl → C2H5Cl + H2O D. C2H4 + HCl → C2H5Cl
A student stirred 0.030 mol of solid sodium hydrogencarbonate into 40 cm3 of a 1.0 mol dm−3 solution of ethanedioic acid. H2C2O4(aq) + 2 NaHCO3(s) → Na2C2O4(aq) + 2 CO2(g) + 2 H2O(l) The temperature of the solution fell from…
Which are units for rate of reaction? A. s mol−1 dm3 B. mol dm−3 min C. mol dm−3 min−1 D. mol min−1