A. Formation of a gas. You can tell a chemical reaction has occurred through: formation of a precipitate, formation of a gas (also known as bubbles) unexpected color change, unexpected odor change, temperature change.
Answer:
Hope it helped
Explanation:
For neutral atoms, the number of valence electrons is equal to the atom's main group number. The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.
<span>It is known that amu is equal to the molar mass of 1 mole of substance. Therefore,
</span>
Weight of one mole of uranium = 238 g/mol
The molar mass or molecular weight for U205 is 556 g/mol.
(238 x 2) + (16 x 5) = 556 g/mol
You add solute until it can't dissolve anymore.