That really depends on the age of the periodic table you’re referring to. Mendeleev’s original periodic table had only 50 elements. Today, the most modern Periodic table has 118 elements.
Answer:
16.8128 grams of sodium azide is needed
Explanation:
2NaN3 = 2Na + 3N2
molar mass of NaN3 =

molar mass of N2

moles of N2 =
moles=mass/R.F.M
16.55÷42 = 0.3940
mole ratio=
2NaN3 : 3N2
3 = 0.3940
2=?

Mass of sodium azide =64×0.2627
=16.8126
Answer: 1.4 moles
Explanation:
I can only assume you are looking for the amount of moles in 0.4M. the capital M means Molarity.
Molarity=moles of solute/liters of solution
Since we know the molarity is 0.4, we can plug this into our equation

moles= 1.4
Answer: A thermal conductor is a material that allows energy in the form of heat, to be transferred within the material, without any movement of the material itself.
Explanation: