Find the mass of 3.50x10^23 molecules of nitrogen gas

16.27 g.

Explanation:

Using cross multiplication:

1.0 mol of N₂ gas contains → 6.022 x 10²³ molecules.

??? mol of N₂ gas contains → 3.50 x 10²³ molecules.

∴ The no. of moles of N₂ gas = (1.0 mol)(3.50 x 10²³ molecules)/(6.022 x 10²³ molecules) = 0.5812 mol.

∴ The mass of 3.50 x 10²³ molecules of N₂ gas = (no. of moles)*(molar mass) = (0.5812 mol)(28.0 g/mol) = 16.27 g.

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.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.