Answer:
The correct option is C.
In a tightly closed container in a dry and well-ventilated place
Explanation:
Hydrogen peroxide should be store in a tight closed container and ventilated area because it is an oxidizing agent and it's has oxidizing characteristics. If to is exposed or the bottle lid is broken and exposed it can react and liberate oxygen and heat. It can react with the air and chemical it is exposed with. This will make it to be less effective and there will be a change in it's composition.
There are 8.61 × 10²⁰ atoms in 0.290 g P₂O₅.
Step 1. Convert <em>grams of P₂O₅ to moles of P₂O₅</em>.

Step 2. Convert <em>moles of P₂O₅ to molecules of P₂O₅</em>.


Step 3. Convert <em>molecules of P₂O₅ to atoms</em>.
There are seven atoms in 1 mol P₂O₅.
∴ 
Answer:
V ∝ n
Step-by-step explanation:
Suppose that pressure and temperature are constant.
If you try to force more molecules of air into a balloon, the balloon will expand.
This is an example of <em>Avogadro's Law</em>: the volume of a gas is directly proportional to the number of moles (particles).
V ∝ n
13. D
14. A
15. C
16. B
17. F
18. E
P = pressure, V = volume, T = absolute temperature k = constant.