The mass of an atom of beryllium is 1.5 x 10^-26 kg. how many beryllium atoms are present in beryllium film of mass 0.37 g used as a window on an x-ray tube? answer in units of atoms.

There are 2.5 * 10^22 beryllium atoms in 0.37 grams

Explanation:

Step 1: Data given

The mass of an atom of beryllium is 1.5 x 10^-26 kg.

Total mass = 0.37 grams

Step 2: Calculate number of atoms

1 atom = 1.5 * 10 ^-26 kg

X atoms = 0.00037 kg

X = 0.00037/1.5*10^-26

X = 2.467 * 10^22 atoms ≈ 2.5 * 10^22 atoms

There are 2.5 * 10^22 beryllium atoms in 0.37 grams

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