The published study of Nurrenbern and Pickering in 1987 raises awareness among chemistry educators that students' success in answering numerical questions does not necessarily reflect their degree of understanding of the related chemical concepts. Efforts have been made to provide more opportunities for students to improve their ability in answering pictorial questions in many studies in the hope that this will explore their conceptual understanding. The aim of this study was to examine the difference between students' ability to answer algorithmic and pictorial type questions of equivalent content and level in the area of chemical kinetics. The respondents involved in this study were 335 Indonesian and UK university chemistry students. Equivalent algorithmic and pictorial question pairs in the topic of chemical kinetics were designed within a four-tier instrument. The results confirm that students' ability to respond to the two types of questions is significantly different. The scores obtained by students in the two types of questions indicate that students' performance in algorithmic questions is better than their performance in pictorial questions. The implications for teaching and learning chemical kinetics are also discussed.