Mole is a unit that has become the way of scientist and those who are interested in the filed to count the number of substances or atoms. Thus, the answer is letter B. It will be very impractical for them to count the atoms using the natural numbers are they are very small and very numerous.
Answer:
0.59
Explanation:
Is 0.59 because you are dividing 35.0g by 58.5 which will than give you 0.59
Perihelion is when a planet is closest to the sun and aphelion is when it is farthest from the sun. Perihelion is the correct answer.
The black coloured precipitate that form is IRON ll SULPHIDE, FeS.
Iron sulphide ll sulphide is black in colour and is insoluble in water. It possess very high melting temperature and react in acids. Iron ll sulphide is used as pigment in hair dyes, glasses, bottles and paints. It is also used as lubricant.
The value of x : 2
<h3>Further explanation</h3>
Semi-normal Hydrochloric acid solution = 0.5 N = 0.5 M
for titration :
M₁V₁n₁=M₂V₂n₂(1=HCl,2=Na₂CO₃)
MW Na₂CO₃.xH₂O=143
MW Na₂CO₃.xH₂O = MW Na₂CO₃+ MW xH₂O = 143
MW Na₂CO₃ = 106 g/mol
MW xH₂O = 18x
Equation :