Identifies the number of protons a single atom of the element contains.
The atomic number helps people identify elements according to the number of protons one atom of the element has. It essentially defines the element
Answer:
Use a 10 mL pipet and a 50 mL volumetric flask, <em>twice</em>
Explanation:
Given those conditions, in order to have a solution that is 25 times less concentrated that the one previously prepared, we would need two dillution steps, as suggested by the problem.
If we take an aliquot of 10 mL and dilute it to a final volume of 50 mL, we prepare a solution that is 5 times less concentrated. And if we then take again an aliquot of 10 mL of that dilluted solution and dilute it to a final volume of 50 mL, we would have a solution 25 (5 times 5) times less concentrated than the original one.
In order to verify, we can calculate the resulting concentration and compare it with the original one:

Thus we can see that the obtained concentration is in fact 25 times lower than the original concentration.
I think that your answer would be evaporation
Answer:
n = 5
Explanation:
methane => 1 Carbon => CH₃
ethane => 2 Carbons => C₂H₆
propane => 3 Carbons => C₃H₈
butane => 4 Carbons => C₄H₁₀
pentane => 5 Carbons => C₅H₁₂
hexane => 6 Carbons => C₆H₁₄
heptane => 7 Carbons => C₇H₁₆ => CH₃(CH₂)₅CH₃
Octante => 8 Carbons => C₈H₁₈
Nonane => 9 Carbons => C₉H₂₀
Decane => 10 Carbons => C₁₀H₂₂