<span>The law of conservation of mass states that, "Mass can neither be created nor destroyed, only its form changes with respect to different forms of energy."
In any reaction, say 10 gms of water is decomposed into its constituents Hydrogen and Oxygen. But the mass remains conserved for the reaction. Although mass and energy are inter-convertible. But,the net mass/energy remains conserved i.e. the mass of products will be equal to the mass of reactants. </span>
<u>Answer:</u> The mass of 1 mole of lithium is 6.941 grams.
<u>Explanation:</u>
To calculate the mass of a compound or element, we use the formula used to calculate the number of moles:

Where,
Number of moles of lithium = 1 mole
Given mass of lithium = ? g
Molar mass of lithium = 6.941 g/mol
Putting value in above equation, we get:

Hence, the mass of 1 mole of lithium is 6.941 grams.
Answer:
Oxygen
Explanation:
Oxygen has 6 valence electrons and it wants to have 8 to obtain a stable octet. So Oxygen gains two electrons in the bond, developing an anion.
It is also a non-metal, and they tend to gain anions.
Answer:During a chemical reaction, all of the atoms that make up the reactants rearrange to form the products.
Explanation:
During a chemical reaction, atoms cannot be created or destroyed.