Faculty from the chemistry and English departments have developed a combined second-semester honors general chemistry and college writing course that fosters critical thinking through challenging writing assignments. Examples of case-study writing assignments and guidelines are provided that faculty at other institutions can adapt in similar small-enrollment lower-division chemistry classes. Recommendations for the writing assignments are provided based on our experiences in developing and implementing them. These recommendations include (i) considering pedagogical principles that define instructional objectives, audience, interest and relevance, critical thinking, clarity, document design, scaffolding, scheduling, and evaluation; (ii) providing appropriate references which students use to formulate their arguments; (iii) posing ill-formed problems for students to engage course content and think critically; and (iv) staging these assignments in multiple drafts throughout the semester with detailed grading criteria provided. This guidance is necessary for such lower-division students to strengthen their college-level academic writing skills and increase their knowledge of chemistry content. (Contains 2 tables.)