{"id":8588,"date":"2024-08-05T22:06:51","date_gmt":"2024-08-06T01:06:51","guid":{"rendered":"https:\/\/xequematenem.com.br\/blog\/?p=8588"},"modified":"2024-09-09T19:29:07","modified_gmt":"2024-09-09T22:29:07","slug":"questao-124-enem-ppl-2018","status":"publish","type":"post","link":"https:\/\/xequematenem.com.br\/blog\/questao-124-enem-ppl-2018\/","title":{"rendered":"Quest\u00e3o 124 \u2013 ENEM PPL 2018"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">O aproveitamento integral e racional das mat\u00e9rias-primas lignocelul\u00f3sicas poder\u00e1 revolucionar uma s\u00e9rie de segmentos industriais, tais como o de combust\u00edveis, mediante a produ\u00e7\u00e3o de bioetanol de segunda gera\u00e7\u00e3o. Este processo requer um tratamento pr\u00e9vio da biomassa, destacando-se o uso de \u00e1cidos minerais dilu\u00eddos. No pr\u00e9-tratamento de material lignocelul\u00f3sico por via \u00e1cida, empregou-se uma <strong>solu\u00e7\u00e3o de \u00e1cido sulf\u00farico, que foi preparada diluindo-se 2 000 vezes uma solu\u00e7\u00e3o de \u00e1cido sulf\u00farico, de concentra\u00e7\u00e3o igual a 98 g\/L , ocorrendo dissocia\u00e7\u00e3o total do \u00e1cido na solu\u00e7\u00e3o dilu\u00edda.<\/strong> O quadro apresenta os valores aproximados de logaritmos decimais<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"885\" height=\"129\" src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-185.png\" alt=\"\" class=\"wp-image-8589\" title=\"\" srcset=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-185.png 885w, https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-185-300x44.png 300w, https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-185-768x112.png 768w\" sizes=\"(max-width: 885px) 100vw, 885px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Sabendo-se que as massas molares, em g\/mol, dos elementos H, O e S s\u00e3o, respectivamente, iguais a 1, 16 e 32, <strong>qual \u00e9 o pH da solu\u00e7\u00e3o dilu\u00edda de \u00e1cido sulf\u00farico preparada conforme descrito?<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A) 2,6<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B) 3,0<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C) 3,2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D) 3,3<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">E) 3,6<\/p>\n\n\n\n<p class=\"has-text-align-center has-large-font-size wp-block-paragraph\"><strong>Solu\u00e7\u00e3o<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Primeiro, vamos encontrar a concentra\u00e7\u00e3o da solu\u00e7\u00e3o dilu\u00edda e, em seguida, calcular o pH.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Dados:<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&#8211; Concentra\u00e7\u00e3o da solu\u00e7\u00e3o original de \u00e1cido sulf\u00farico: 98 g\/L<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">&#8211; Fator de dilui\u00e7\u00e3o: 2000 vezes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A concentra\u00e7\u00e3o de 98 g\/L equivale a concentra\u00e7\u00e3o molar de 1 mol\/L, j\u00e1 que a massa molar do \u00e1cido sulf\u00farico \u00e9 igual a 98 g\/mol. Considerando que a solu\u00e7\u00e3o foi dilu\u00edda 2000 vezes, a nova concentra\u00e7\u00e3o da solu\u00e7\u00e3o dilu\u00edda \u00e9 dada por:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img decoding=\"async\" width=\"174\" height=\"36\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-186.png\" alt=\"\" class=\"wp-image-8590 lazyload\" style=\"--smush-placeholder-width: 174px; --smush-placeholder-aspect-ratio: 174\/36;width:121px;height:auto\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\"><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">em que:<\/p>\n\n\n\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-2c90304e wp-block-group-is-layout-flex\">\n<p class=\"wp-block-paragraph\">M<sub>1<\/sub> = concentra\u00e7\u00e3o molar inicial = 1 mol\/L<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V<sub>1<\/sub> = volume inicial = V<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">M<sub>2<\/sub> = concentra\u00e7\u00e3o molar final<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V<sub>2<\/sub> = 2000V<\/p>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Ao substituir os valores, temos:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img decoding=\"async\" width=\"282\" height=\"115\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-187.png\" alt=\"\" class=\"wp-image-8591 lazyload\" style=\"--smush-placeholder-width: 282px; --smush-placeholder-aspect-ratio: 282\/115;width:211px;height:auto\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\"><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Determina\u00e7\u00e3o do pH<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">O \u00e1cido sulf\u00farico (H<sub>2<\/sub>\u200bSO<sub>4<\/sub>\u200b) \u00e9 um \u00e1cido forte e se dissocia completamente em solu\u00e7\u00e3o aquosa. A dissocia\u00e7\u00e3o \u00e9:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>H<sub>2<\/sub>SO<sub>4<\/sub> \u2192 2 H<sup>+<\/sup> + SO<sub>4<\/sub><sup>2-<\/sup><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Para cada mol do \u00e1cido s\u00e3o gerados 2 mols de H<sup>+<\/sup>. Portanto, a concentra\u00e7\u00e3o de \u00edons hidrog\u00eanio ser\u00e1 o dobro da concentra\u00e7\u00e3o da solu\u00e7\u00e3o dilu\u00edda de \u00e1cido sulf\u00farico:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>[H+] = 2 \u00d7 0,0005&nbsp;mol\/L = 0,001&nbsp;mol\/L<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Finalmente, calculamos o pH usando a f\u00f3rmula:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img decoding=\"async\" width=\"258\" height=\"108\" data-src=\"https:\/\/xequematenem.com.br\/blog\/wp-content\/uploads\/2024\/08\/image-188.png\" alt=\"\" class=\"wp-image-8592 lazyload\" style=\"--smush-placeholder-width: 258px; --smush-placeholder-aspect-ratio: 258\/108;width:186px;height:auto\" title=\"\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\"><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Alternativa B<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>O aproveitamento integral e racional das mat\u00e9rias-primas lignocelul\u00f3sicas poder\u00e1 revolucionar uma s\u00e9rie de segmentos industriais, tais como o de combust\u00edveis, mediante a produ\u00e7\u00e3o de bioetanol de segunda gera\u00e7\u00e3o. Este processo requer um tratamento pr\u00e9vio da biomassa, destacando-se o uso de \u00e1cidos minerais dilu\u00eddos. No pr\u00e9-tratamento de material lignocelul\u00f3sico por via \u00e1cida, empregou-se uma solu\u00e7\u00e3o de [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":8589,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[87,97],"tags":[],"area-do-conhecimento":[116,120],"assunto":[],"class_list":["post-8588","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-questoes-ppl","category-2018-questoes-ppl","area-do-conhecimento-ciencias-da-natureza-e-suas-tecnologias","area-do-conhecimento-quimica"],"_links":{"self":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/8588","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/comments?post=8588"}],"version-history":[{"count":1,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/8588\/revisions"}],"predecessor-version":[{"id":8593,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/posts\/8588\/revisions\/8593"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/media\/8589"}],"wp:attachment":[{"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/media?parent=8588"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/categories?post=8588"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/tags?post=8588"},{"taxonomy":"area-do-conhecimento","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/area-do-conhecimento?post=8588"},{"taxonomy":"assunto","embeddable":true,"href":"https:\/\/xequematenem.com.br\/blog\/wp-json\/wp\/v2\/assunto?post=8588"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}