Which of these statements is true?

a. chemical energy is a form of potential energy.

b. chemical energy is a form of nuclear energy.

c. chemical energy is associated with moving electrons.

d. chemical energy is associated with molecular motion.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

you gotta add the following molecules so we can give u an answer

explanation: