Quiz — redox et electricité.pdf

Question 1 sur 10 20:00

[{"id":57937,"question":"Quel est l'oxydant dans le couple MnO₄⁻\/Mn²⁺ ?","option_a":"MnO₄⁻","option_b":"Mn²⁺","option_c":"O₂","option_d":"H⁺","option_e":"","option_f":"","bonne_reponse":"a","explication":"L'oxydant est l'espèce qui capte des électrons. Dans le couple MnO₄⁻\/Mn²⁺, MnO₄⁻ est réduit en Mn²⁺, donc c'est l'oxydant.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"MnO₄⁻\", \"b\": \"Mn²⁺\", \"c\": \"O₂\", \"d\": \"H⁺\"}}","_debug_options_count":4},{"id":57938,"question":"Dans une pile Daniell, l'électrode de zinc est le siège d'une réaction d'oxydation.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai. Le zinc, moins noble que le cuivre, s'oxyde en Zn²⁺ et libère des électrons, alimentant le circuit.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":57939,"question":"Quelle est l'unité de la force électromotrice (f.é.m.) d'une pile ?","option_a":"Volt (V)","option_b":"Ampère (A)","option_c":"Watt (W)","option_d":"Coulomb (C)","option_e":"","option_f":"","bonne_reponse":"a","explication":"La f.é.m. est une différence de potentiel, donc elle s'exprime en volts (V).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Volt (V)\", \"b\": \"Ampère (A)\", \"c\": \"Watt (W)\", \"d\": \"Coulomb (C)","_debug_options_count":4},{"id":57940,"question":"Quel est le rôle de la pont salin dans une pile ?","option_a":"Maintenir l'électroneutralité des solutions","option_b":"Augmenter la f.é.m.","option_c":"Stocker les électrons","option_d":"Réguler la température","option_e":"","option_f":"","bonne_reponse":"a","explication":"Le pont salin permet la circulation des ions pour équilibrer les charges dans les deux demi-piles, assurant ainsi la continuité du courant.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Maintenir l'électroneutralité des solutions\", \"b\": \"Augmenter l","_debug_options_count":4},{"id":57941,"question":"La réaction Zn + Cu²⁺ → Zn²⁺ + Cu est spontanée.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai. Le zinc est plus réducteur que le cuivre, donc la réaction se produit spontanément, libérant de l'énergie.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":57942,"question":"Quelle loi relie la tension aux bornes d'un conducteur ohmique à l'intensité du courant qui le traverse ?","option_a":"Loi de Joule","option_b":"Loi d'Ohm","option_c":"Loi de Faraday","option_d":"Loi de Lenz","option_e":"","option_f":"","bonne_reponse":"b","explication":"La loi d'Ohm stipule que U = R × I, où U est la tension, R la résistance et I l'intensité du courant.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Loi de Joule\", \"b\": \"Loi d'Ohm\", \"c\": \"Loi de Faraday\", \"d\": \"Loi","_debug_options_count":4},{"id":57943,"question":"Dans une pile en décharge, la masse de l'anode :","option_a":"Augmente","option_b":"Diminue","option_c":"Reste constante","option_d":"Devient nulle","option_e":"","option_f":"","bonne_reponse":"b","explication":"L'anode est le siège de l'oxydation. Sa masse diminue car le métal s'oxyde en ions.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Augmente\", \"b\": \"Diminue\", \"c\": \"Reste constante\", \"d\": \"Devient ","_debug_options_count":4},{"id":57944,"question":"Le potentiel standard d'un couple redox est mesuré dans des conditions standards.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai. Le potentiel standard est défini pour une température de 25°C, une pression de 1 bar et des concentrations de 1 mol\/L.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":57945,"question":"Quelle est la relation entre la f.é.m. d'une pile et la constante d'équilibre de la réaction ?","option_a":"E = (RT\/nF) ln K","option_b":"E = K \/ (RT\/nF)","option_c":"E = RT \/ (nF ln K)","option_d":"E = nF \/ (RT ln K)","option_e":"","option_f":"","bonne_reponse":"a","explication":"La relation est donnée par l'équation de Nernst : E = E° - (RT\/nF) ln Q, où Q est le quotient réactionnel. À l'équilibre, Q = K.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"E = (RT\/nF) ln K\", \"b\": \"E = K \/ (RT\/nF)\", \"c\": \"E = RT \/ (nF ln ","_debug_options_count":4},{"id":57946,"question":"Un accumulateur peut être rechargé car sa réaction est réversible.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Vrai. Contrairement aux piles, les accumulateurs utilisent des réactions chimiques réversibles, permettant de recharger l'appareil.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4}]