Answer:
Explanation:
Q1) as we know that moles=given mass/molar mass
mass of 5 moles of Mg is
mass =moles*molar mass
mass=5*24
mass=120 g
mass of 5 moles of CaCO3 is
mass= moles*molar mass
mass=5*100=500
Q2) number of atoms in 10 g Na
first we need number of moles of sodium
moles =mass/molar mass
moles=10/23=0.43
now we know that moles=number of atoms /avogadro number
for number of atom the formula become
number of atom=moles*avogadro number
number of atom=0.43*6.023*10^23=2.6*10^23
Q3)number of molecule in 10 g of NaCl
again we need number of moles of NaCl
moles=given mass/molar mass
moles=10/58.5=0.17
now number of molecules=moles*avogadro number
number of molecules=0.17*6.023*10^23=1.02*10^23
Q4) avogadro number is the number of particles(atoms,molecules,ions) present in one mole of a substance its value is 6.023*10^23
Q5)Number of atoms in 4g of oxygen
again we need number of moles of oxygen
moles=mass/molar mass
moles=4/16=0.25
now number of atoms=moles*avogadro number
number of atoms=0.25*6.023*10^23 =1.5*10^23
