Anne prepares a solution of copper nitrate with a concentration of 30 g/dm³. what mass of copper nitrate did she add to 100cm³ of water, in grams?

3 g

Explanation:

Concentration of copper nitrate needed = 30 g/dm³

Volume of water = 100 cm³ = 0·1 dm³

( ∵ 1 dm³ = 1000 cm³)

Let the mass of copper nitrate that should be added to 100 cm³ water be m g

m ÷ 0·1 = 30

∴ m = 3 g

∴ Mass of copper nitrate that should be added to 100 cm³ of water = 3 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.

gold is my favorite solid.