Quiz — Détermination de l’ordre à partir des vitesses initiales.pdf

Question 1 sur 10 20:00

[{"id":89541,"question":"Quel est l’ordre d’une réaction si la vitesse est indépendante de la concentration du réactif ?","option_a":"Ordre 0","option_b":"Ordre 1","option_c":"Ordre 2","option_d":"Ordre fractionnaire","option_e":"","option_f":"","bonne_reponse":"a","explication":"Si la vitesse ne dépend pas de la concentration, l’ordre est 0 (vitesse = 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\": \"Ordre 0\", \"b\": \"Ordre 1\", \"c\": \"Ordre 2\", \"d\": \"Ordre fractionnai","_debug_options_count":4},{"id":89542,"question":"La loi de vitesse s’écrit v = k[A]^n. Si n=1, la réaction est d’ordre 1.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, si n=1, la vitesse est proportionnelle à la concentration de A, donc ordre 1.","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":89543,"question":"Pour une réaction d’ordre 2, si on double la concentration initiale, la vitesse initiale :","option_a":"Double","option_b":"Quadruple","option_c":"Reste inchangée","option_d":"Diminue de moitié","option_e":"","option_f":"","bonne_reponse":"b","explication":"Pour un ordre 2, v = k[A]^2. Si [A] double, v quadruple (2^2 = 4).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"Double\", \"b\": \"Quadruple\", \"c\": \"Reste inchangée\", \"d\": \"Diminue","_debug_options_count":4},{"id":89544,"question":"L’unité de la constante de vitesse k dépend de l’ordre de la réaction.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, par exemple : mol\/L\/s pour ordre 0, s^-1 pour ordre 1, L\/mol\/s pour ordre 2.","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":89545,"question":"Si la vitesse initiale est multipliée par 8 lorsque la concentration initiale est doublée, l’ordre de la réaction est :","option_a":"Ordre 0","option_b":"Ordre 1","option_c":"Ordre 2","option_d":"Ordre 3","option_e":"","option_f":"","bonne_reponse":"d","explication":"Si [A] double et v est multipliée par 8 (2^3), alors l’ordre est 3 (2^3 = 8).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"d\", \"options\": {\"a\": \"Ordre 0\", \"b\": \"Ordre 1\", \"c\": \"Ordre 2\", \"d\": \"Ordre 3\"}}","_debug_options_count":4},{"id":89546,"question":"La méthode des vitesses initiales permet de déterminer l’ordre partiel par rapport à chaque réactif.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, en faisant varier la concentration d’un réactif à la fois, on isole son ordre partiel.","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":89547,"question":"Pour une réaction A → produits, si la vitesse initiale est divisée par 4 lorsque [A] est divisée par 2, l’ordre est :","option_a":"Ordre 0","option_b":"Ordre 1","option_c":"Ordre 2","option_d":"Ordre 3","option_e":"","option_f":"","bonne_reponse":"c","explication":"Si [A] est divisée par 2 et v est divisée par 4 (2^2), l’ordre est 2.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"c\", \"options\": {\"a\": \"Ordre 0\", \"b\": \"Ordre 1\", \"c\": \"Ordre 2\", \"d\": \"Ordre 3\"}}","_debug_options_count":4},{"id":89548,"question":"L’ordre global d’une réaction est toujours égal à la somme des ordres partiels.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, l’ordre global est la somme des ordres partiels par rapport à chaque réactif.","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":89549,"question":"Si une réaction est d’ordre 1, son temps de demi-réaction est indépendant de la concentration initiale.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, pour un ordre 1, t1\/2 = ln(2)\/k, indépendant de [A]0.","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":89550,"question":"La constante de vitesse k peut être déterminée à partir de la pente d’un graphique de ln(v) en fonction de ln([A]).","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Oui, car ln(v) = ln(k) + n·ln([A]), donc la pente donne l’ordre n.","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}]