A first order reaction is 40% completed in 30 minutes. what fraction of reactant remains at 40 minute?

The image below shows numerous volcanic mountains in the pacific northwest. what is the most likely cause of the volcanic and earthquake activity in this region?

How are the crust and the inner core alike? a) they are both solid. b) they both have the same temperature. c) they are both under the same pressure. d) they are both very close to the center of the earth.

Acoil suspended freely, points in some direction when no current is passed through it . can you tell what will happen when a current is passed though it?