10.2 Configuring IP Standard Access Lists
10.2.3 Outbound access list processing
As shown in the main figure, for outbound standard IP access lists, after receiving and routing a packet to a controlled interface, the router checks the source address of the packet against the access list. If the access list permits the address, the router transmits the packet. If the access list denies the address, the router discards the packet and returns an ICMP "Admin Denied" message.

When configuring outbound access lists, order is important (just as it is with inbound access lists). Make sure you list the entries in order from specific to general.