Problem solving and critical thinking are buzzwords used in defining general chemistry learning goals. Assessments including well-structured homework, quizzes, and exams are designed and incorporated to build these skills. Our research expanded upon the types of assessments and analyzed the effect of writing assignments for promoting problem solving, critical thinking, and retention in acid-base chemistry. Calibrated Peer Review (CPR) was used to implement writing assignments in a large enrollment two-quarter introductory sequence with the writing activities strongly emphasizing qualitative and quantitative problems in acid-base chemistry. To measure the effectiveness of assigning small writing assignments, students in the treatment course were compared to the honors students (control group) who have historically demonstrated stronger abilities in acid-base chemistry, especially in subsequent organic chemistry courses. Data was collected using interviews in which students verbally explained their answers and rationale for a set of six questions on acid-base chemistry. The control group was interviewed 10 weeks after instruction, and the treatment group was interviewed immediately after instruction (prior to the writing assignment) and 10 weeks following instruction and the writing assignment. Both the treatment and control groups were completing organic chemistry during the post-10-week interview. The treatment group was interviewed twice to gauge retention and make a comparison with the control group. Statistical differences in performance (using a 95% level of confidence) were not observed between the 10-week post-treatment and instruction interviews between the control and treatment groups, supporting the conclusion that the writing assignment aided in closing the gap in student abilities between the honors and introductory courses.