Ineed an answer asap

how do scientists determine the number of neutrons in an isotope of an atom?

they subtract the number of protons from the mass number.

they subtract the number of electrons from the mass number.

they subtract the number of protons and neutrons from the mass number.

they add the number of protons and electrons.

Scientists can calculate the number of neutrons by subtracting the atomic number from the atomic mass.

they subtract the protons

h

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"