The Conquest and Challenge YouCat number for April is all about prayer.
#478 Why can we be confident that our prayer is heard by God?
Many people called on Jesus during his earthly life for healing, and their prayers were answered. Jesus listens to our petitions and brings them to the Father. Jesus performed signs and miracles. The lame, the lepers, and the blind did not ask Jesus in vain. There are testimonies also of prayers answered by all the saints of the Church. Many Christians can tell stories of how they called to God and God heard their prayer. We must leave it up to God how he will answer our petitions.