Thorium (atomic mass 230, atomic number 90) decays by releasing 2 alpha particles to form the isotope

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

zfoods? ok, pressure is used to keep the heat inside and to keep the food perfect.

the answers would be

the first one and the second one