What happens when a catalyst is added to a chemical reaction that is already in progress?

the reaction reverses

the reaction stops

the rate of the chemical reaction decreases

the reaction with the lower activation energy occurs

The p sub shell can hold up to 8 electrons in an atom. true or false?

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?

A40 kilogram skier starts at the top of a 12 meter high slope. at the bottom, she is travelling 10 meters per second. how much energy does she lose to friction