Calculate the mass percent composition of O in each compound. a. calcium nitrate
b. Iron(II) sulfate
c. Carbon dioxide

A. Mass percent composition of oxygen = 58.5%

B. Mass percentage composition of oxygen = 42.1%

C. Mass percentage composition of oxygen = 72.7 %

Explanation:

Percentage mass composition of an element in a compound is given by the formula below:

Percentage mass composition = mass of element/ molar mass of compound × 100%

Percentage mass of oxygen in the given compounds are then calculated.

a. Calcium nitrate, Ca(NO₃)₂: molar mass of compound is obtained first.

Molar mass of Ca(NO₃)₂ = 40 + 14 × 2 + 16 × 2 × 3 = 164 g

Mass of oxygen = 16 × 6 = 96 g

Mass percent composition of oxygen = 96/164 × 100% = 58.5%

b. Iron (ii) sulfate, FeSO₄: molar mass of compound is obtained first.

Molar mass of FeSO₄ = 56 + 32 + 16 × 4 = 152 g

Mass of oxygen = 16 × 4 = 64 g

Mass percentage composition of oxygen = 64/152 × 100% = 42.1%

c. Carbon dioxide, CO₂: molar mass of compound is obtained first.

Molar mass of CO₂ = 12 + 16 × 2 = 44 g

Mass of oxygen = 16 × 2 = 32 g

Mass percentage composition of oxygen = 32/44 × 100% = 72.7 %

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

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.