Helium has the smallest atomic radius® Α⇒Ω
Answer:
Explanation:
Num of molecules = num of moles * Avogadro's constant (6.02* 10^23)
But num of moles = reacting mass / molar mass
Molar mass of H20= 2*1 + 16 = 2+16 = 18g
Reacting mass of H20 = 0.55g
Therefore, num of moles of H20 = 0.55g/18g = 0.031 moles
Therefore, num of molecules of H20 = 0.031 * 6.02*10^23
= 1.87*10^22 molecules of H20
Answer:
4.858 g
Explanation:
Start with the formula
density = 
density = 1.98 g/mL
volume = 2.45 mL
mass = ??
rearrange the formula to solve for mass
(density) x (volume) = mass
Add in the substitutes and solve for mass
1.98 g/mL x 2.45 mL = 4.858 g