1. write a balanced double replacement chemical equation. (4 points) 2. for the above equation, demonstrate that it obeys the law of conservation of mass. (4 points) 3. what quantities are always conserved in a chemical reaction? (2 points)

1. A double replacement chemical equation is a reaction in which the cations and anions of the compounds that react exchange their positions forming new compounds. Double replacement reaction usually leads to the formation of water, a precipitate or a gas as one of the products.

Example of a double replacement reaction:

2. The above equation obeys the Law of conservation of mass as the number of atoms of each element on the reactant side is equal to that of the product side. So the overall mass on reactant side will be equal to that on the product side.

Mass of each reactant per mole:

Total mass on reactant side = (110.98+142.04) g/mol= 253.02g/mol

Mass of each product per mole:

Total mass on product side = (136.14+116.88)g/mol=253.02g/mol

Total mass on reactant side = Total mass on product side =253.02g/mol

So, it obeys the law of conservation of mass as the total mass remains same before and after the reaction.

3. In a chemical reaction, mass is conserved that means the mass of reacting species is equal to the mass of the products formed. Similarly the total number of atoms of each element is also conserved in a chemical reaction.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

answer; natural resources;