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A solution contains 2.0 g of one enantiomer of a chiral compound and 2.0 g of its mirror image in 100 cm3. The pure first enantiomer, at this concentration, rotates the plane of polarized light by +34.0° under the same conditions. What…
Boron trifluoride reacts with ammonia to form an adduct. BF3 + NH3 → H3N−BF3 Which terms describe boron trifluoride in this reaction? A. Electrophile and Lewis base B. Nucleophile and Lewis acid C. Nucleophile and Lewis base D. Electrophile and Lewis…
In the nitration of benzene with a mixture of concentrated nitric acid and concentrated sulfuric acid, the nitronium ion, NO2+, attacks the benzene ring. What is the role of NO2+ and what type of reaction takes place? A. Nucleophile; nucleophilic…
A student determined the enthalpy of combustion of a fuel as −680 kJ mol−1. The literature value is −850 kJ mol−1. What is the percentage error of the experimental result? A. 20 % B. 25 % C. 80 % D. 125 %
A student determines the formula of hydrated copper(II) sulfate, CuSO4 ⋅ x H2O, by heating a weighed sample until its mass is constant. Which observation would explain a systematic error in the value of x? A. The crucible was always weighed while it was…
Which compound produces the 1H NMR spectrum shown? The areas under the two signals are in the ratio 1 : 1. A. CH3COCH3 B. CH3COOCH3 C. CH3COOCH2CH3 D. CH3OCH3
The graph shows how the concentration of dinitrogen pentaoxide, N2O5, changes with time during its decomposition at constant temperature. What is the average rate of reaction, expressed as the rate of decrease in the concentration of N2O5, over…
Ethane burns completely in oxygen to give carbon dioxide and water. C2H6(g) + O2(g) → CO2(g) + H2O(l) What is the C2H6 : O2 mole ratio in the balanced equation, written with the smallest whole-number coefficients? A. 1:3 B. 2:5 C. 2:7 D.…
Propanoic acid, CH3CH2COOH, is the next member of the series. Outline two characteristics that make ethanoic acid and propanoic acid members of the same homologous series.
Calculate the percentage by mass of carbon in ethanoic acid.