Asample of marble has a volume of 8 cm3 and a density of 2.75 g/cm3. what is its mass?
0.34 g
2.9 g
10.75 g
22 g

The correct answer is 22 g.

Explanation:

The expression for the relation between mass and density is as follows;

Here, m is the mass of the object and V is the volume of the object.

It is given in the problem that A sample of marble has a volume of and a density of  .

Calculate the mass of a sample marble.

Put and .

m=22 g

Therefore, the mass of a sample of a marble is 22 g.

c is the answer because when something is left after something evaporates that shows the chemical change.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-