Which of these is an example of a chemical change? dissolving two cups of flour in a liter of water pouring water from a large trough into a beaker decreasing the motion of water molecules by freezing forming oxygen by bubbling fluorine through water

Forming oxygen By bubbling flourine through water

Explanation:

Chemical change is the change in which chemical composition of the substance changes by rearrangement of atoms.

Physical change is a change in which only the physical properties such as size, shape etc change and there is no rearrangement of atoms.

1. Dissolving two cups of flour in a liter changes the state and hence is a physical change.

2. Pouring water from a large trough into a beaker is a physical change.

3. Decreasing the motion of water molecules by freezing changes the state and hence is a physical change.

4. Forming oxygen By bubbling flourine through water involve rearrangement of atoms and thus is a chemical change.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

the answer is minerals.