4.what is the volume of 50.0 g of calcium if the density of calcium is .50 g/ml?

The volume of calcium is 100 ml.

Explanation:

Density is defined as the mass contained per unit volume.

Given : Mass of calcium= 50.0 grams

Density of calcium =

Putting in the values we get:

Thus the volume of calcium is 100 ml.

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

im not exactly sure but i think its b!