Question

Calcium carbonate is a compound that is used to make chalk for drawing on rocks or pavement. One molecule has one atom of calcium (Ca), one atom of carbon (C), and three atoms of oxygen (O). Which is the correct way to write the chemical formula for calcium carbonate?

A.
3CaCO
B.
Ca3CO
C.
CaCO3
D.
Ca3C3O3
using plato

Answer 1

the chemical formula is caca3

Answer 2

C. CaCO₃

Step-by-step explanation:

One formula unit contains the elements calcium, carbon, and oxygen. Start by writing the symbol of the elements:

CaCO

We indicate the number of atoms of each element by writing the number as a subscript following the symbol.

One formula unit contains one atom of Ca, one of C, and three of O, so the formula becomes

Ca₁C₁O₃

Finally, we do not write one as a subscript in a formula. If there is no subscript, we automatically assume that it is one. Thus, the correct formula is

CaCO₃