Answer:
C3H7OH → C3H6 + H20
Explanation:
If we look at the reactant and the product we will realize that the reactant is an alcohol while the product is an alkene. The reaction involves acid catalysed elimination of water from an alcohol.
Water is a good leaving group, hence an important synthetic route to alkenes is the acid catalysed elimination of water from alcohols. Hence the conversion represented by C3H7OH → C3H6 + H20 is an elimination reaction in which water is the leaving group.
Explanation:tr
a) Molar mass of HF = 20 g/mol
Atomic mass of hydrogen = 1 g/mol
Atomic mass of fluorine = 19 g/mol
Percentage of an element in a compound:

Percentage of fluorine:

Percentage of hydrogen:

b) Mass of hydrogen in 50 grams of HF sample.
Moles of HF = 
1 mole of HF has 1 mole of hydrogen atom.
Then 2.5 moles of HF will have:
of hydrogen atom.
Mass of 2.5 moles of hydrogen atom:
1 g/mol × 2.5 mol = 2.5 g
2.5 grams of hydrogen would be present in a 50 g sample of this compound.
c) As we solved in part (a) that HF molecules has 5% of hydrogen by mass.
Then mass of hydrogen in 50 grams of HF compound we will have :
5% of 50 grams of HF = 
CaCO3 + 2KCL ⇒ CaCl2 + K2CO3
It is balanced as so based on the charges given on the periodic table and polyatomic ions.
Calcium has the charge of 2 but CO3 also shares the same charge, thus cancelling that out.
Potassium has a charge of 1 while Chlorine also shares a charge of 1, also cancelling it out.
Thus, if it performs a double replacement reaction, they would take these charges to the new elements that do not cancel out their charges.
Therefore, we need the coefficient of 2 in front of Potassium Chloride in order to balance the equation as on the products side of the equation, Potassium and Chlorine both have a subscript of 2.
Hope this helps!
Take 15/100 X 75 = The answer