Answer:
Titration
Explanation:
The best technique which can be used to determine the number of moles of the HCl in the sample is titration.
The given amount of HCl solution must be titrated with known concentration of the base like NaOH.
The volume of NaOH required must be noted also.
According to the reaction,

At equivalence point
Moles of
= Moles of 
Considering:-
Moles of 
Thus, in this way, moles of HCl can be determined.
Answer:
expands
Explanation:
Most substances become increasingly compressed when frozen solid, but water is a famous exception.
Answer:
Electrons "surround"
Explanation:
Protons and neutrons "make up" the nucleus so they are contained "within" the nucleus meaning that electrons would "surround" the nucleus as they orbit around the nucleus
Answer:
200 liters of fluoridated drinking water would have to be consumed by as person to reach the toxic level.
Explanation:
Toxic level of fluoride ions = 0.2 g per 70 kg body weight
Concentration of fluoride ions in drinking water = 1 mg/ L = 0.001 g/L
1 mg = 0.001 g
Let the volume of drinking water consumed by person to reach the toxic level of fluoride concentration be V.
For 70 kg body weight 0.2 grams of fluoride ions will be toxic.


200 liters of fluoridated drinking water would have to be consumed by as person to reach the toxic level.
Beryllium has an atomic number of 4, so a beryllium atom has 4 protons in its nucleus.
Since the charge of 1 proton is +1 and neutrons in the nucleus have 0 charge, the correct answer is (4) +4.
Hope this helps~