radioisotope cobalt 60, half life 5.3 years has activity of 12,400 cmp how much time has passed if the activity of the sample has dropped to 775 cpm

answer: c.

explanation:

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

bcde is the incorrect answer it is a

air

in a tire you fill a tire with air

then a couple days later you check the air pressure in the tire

hope this mark me brainliest