(a) The repeat unit molecular weight of polypropylene (C\u2083H\u2086) is 42.08 g\/mol<\/strong>.<\/p>\n\n\n\n (b) The number-average molecular weight ((M_n)) for a polypropylene with a degree of polymerization ((DP)) of 15,000 is:<\/p>\n\n\n\n [ [ Polypropylene (PP) is a polymer made up of repeating propylene (C\u2083H\u2086) units. The molecular weight of a polymer depends on its degree of polymerization, which is the number of repeat units in the polymer chain.<\/p>\n\n\n\n The molecular weight is crucial in determining the physical properties of polypropylene, such as tensile strength, melting point, and flexibility. Higher molecular weights generally lead to improved mechanical properties and increased viscosity, making the polymer suitable for various applications like packaging, automotive components, and textiles.<\/p>\n\n\n\n (a) Compute the repeat unit molecular weight of polypropylene. (b) Compute the number-average molecu- lar weight for a polypropylene for which the degree of polymerization is 15,000. The correct answer and explanation is : (a) The repeat unit molecular weight of polypropylene (C\u2083H\u2086) is 42.08 g\/mol. (b) The number-average molecular weight ((M_n)) for a polypropylene […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-199323","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/199323","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=199323"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/199323\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=199323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=199323"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=199323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
M_n = DP \\times \\text{Repeat Unit Molecular Weight}
]<\/p>\n\n\n\n
M_n = 15,000 \\times 42.08 = 631,170 \\text{ g\/mol}
]<\/p>\n\n\n\nExplanation:<\/h3>\n\n\n\n
\n
The molecular weight of the repeat unit in polypropylene is determined by adding the atomic weights of the elements in the propylene monomer (C\u2083H\u2086):<\/li>\n<\/ol>\n\n\n\n\n
\n
The number-average molecular weight ((M_n)) is given by: [
M_n = DP \\times M_{\\text{repeat unit}}
] Given (DP = 15,000), we multiply by 42.08 g\/mol: [
M_n = 15,000 \\times 42.08 = 631,170 \\text{ g\/mol}
] This value represents the average molecular weight of the polymer chains in the sample.<\/li>\n<\/ol>\n\n\n\n![\"\"](\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/03\/image-836.png\")
<\/figure>\n","protected":false},"excerpt":{"rendered":"