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Questions in chemistry

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

[Terjawab] 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. $526.724 mol^{-1} L^{-1}$

[Terjawab] 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

[Terjawab] 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. $C_6H_8O_6$

[Terjawab] Check the correct answer. Which of the following bears a diatomic molecule? i. Helium ii. Nitrogen iii. Sulphur iv. Phosphorus Which of the following is a chemical change? i. Melting of ice ii. Breaking a stone iii. Burning coal iv. Boiling of water Which of the following is an exothermic reaction? i. [tex]$CaO + H _2 O \longrightarrow Ca ( OH )_2$[/tex] ii. [tex]$2 KClO _3 \longrightarrow 2 KCl +3 O _2$[/tex] iii. [tex]$N _2+ O _2 \longrightarrow 2 NO$[/tex] When a piece of granulated zinc was added into the test tube containing dilute HCl, a gas was produced. What gas is it? i. Carbon dioxide ii. Ammonia iii. Oxygen iv. Hydrogen What does the symbol ([tex]$\rightleftharpoons$[/tex]) represent? i. Reactant ii. Product iii. Endothermic reaction iv. Reversible reaction What gas will be produced if [tex]$KClO _3$[/tex] is heated? i. Hydrogen ii. Oxygen iii. Chlorine iv. Potassium If limestone is heated, what will be the products? i. [tex]$Ca ( OH )_2+ O _2$[/tex] ii. [tex]$CaO + CO _2$[/tex] iii. [tex]$CaO + O _2$[/tex] iv. [tex]$KCl + O _2$[/tex]

[Terjawab] Which of the following diatomic molecules is joined by a double covalent bond? A. $O _2$ B. $N _2$ C. $Cl _2$ D. $H _2$

[Terjawab] The formation of which product(s) will most likely be observed in a combustion reaction? A. an oxide B. one element and one compound C. an element D. two ionic compounds

[Terjawab] Select the correct answer. A compound has an empirical formula of $C _2 H _5$. What is true about this empirical formula? A. It models the structure of the compound. B. It shows the ratio of elements in the compound. C. It gives the mass of each atom in the compound. D. It indicates the number of atoms in the compound. E. It describes only this one compound.

[Terjawab] What is [tex]$\Delta S$[/tex] in the equation [tex]$\Delta G=\Delta H-T \Delta S$[/tex] ? A. The change in heat content between the products and the reactants B. The change in free energy between the products and the reactants C. The change in enthalpy between products and reactants in a reaction D. The change in entropy between products and reactants in a reaction

[Terjawab] Mole of sodium hydroxide reacts with one. Calculate the concentration of the hydrochloric acid. [tex]NaCl + HCl[/tex] Why did the temperature of the mixture fall after the maximum temperature had been reached?