What quantity measures the amount of matter in an object?​

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

Can someone me with 6 to 10 plz this is for masteries test.

Which of the following is the correct definition of chemical energy? a. energy an object has because of its motion or position b. energy resulting from the flow of charged particles, such as electrons or ions c. energy produced from the splitting of atoms d. energy stored in chemical bonds of molecules