Hi avocadernize! For chemistry, perhaps it might be helpful for your child to study in a bite-size manner so that the challenging subject seem less overwhelming. Review 1 unit/chapter a day, do a few practice questions, and slowly build confidence. Once your child experiences the sense of achievement that she can master the concepts, slowly she will start finding chemistry less difficult. For chemical reactions, mindmaps might be helpful so that at one glance, she can review and recap easily. Hope this helps!