What is the total number of moles represented by 20 grams of caco3

a. 0.1
b. 0.2
c. 1
d. 2

B. 0.2.

Explanation:

n = mass/molar mass

mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.

∴ n = mass/molar mass = (20 g)/(100.0869 g/mol) = 0.1998 ≅ 0.2 mol.

So, the right choice is: B. 0.2.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.