Emotions play a crucial role in collaboration. They help to make inferences about the partner and can strongly influence task performance. Due to limitations of emotional cues in computer-mediated collaboration (CMC), the collaborative process can be impacted. In this study, we report on the effect of an Emotion Awareness Tool (EAT) designed to facilitate the sharing of emotions between partners, on the perceived emotions after collaboration and the perceived quality of the interaction. Results showed that the EAT stimulated participants to engage in a mutual modeling of emotions. In the EAT condition, the perceived amount of time spent on emotion modeling process was positively correlated to the perceived intensity of positive emotions after collaboration. The EAT increased the perceived degree of transactivity, but only for women. This study provides a first step in exploring the effect of emotion awareness in CMC tasks including a comparing approach for its gender-specific relevance.