100 !

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:

CaCl_{2}(aq)+Na_{2}SO_{4}(aq)-->CaSO_{4}(s)+2NaCl(aq)

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.

CaCl_{2}(aq)+Na_{2}SO_{4}(aq)-->CaSO_{4}(s)+2NaCl(aq)

Mass of each reactant per mole:

(1 * Ca + 2 * Cl)=(1*40.08g/mol) + (2*35.45g/mol)=110.98g/mol

(2*Na)+(1*S)+(4*O)=(2*22.99g/mol)+(1*32.07g/mol)+(4*16.00g/mol)=142.04g/mol

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

Mass of each product per mole:

(1*Ca)+(1*S)+(4*O)=(1*40.08g/mol)+(1*32.06g/mol)+(4*16.00g/mol)=136.14g/mol

(2*Na)+(2*Cl)=(2*22.99g/mol)+(2*35.45g/mol)=116.88g/mol

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.

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Explanation: Look it up next time

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:

CaCl_{2}(aq)+Na_{2}SO_{4}(aq)-->CaSO_{4}(s)+2NaCl(aq)

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.

CaCl_{2}(aq)+Na_{2}SO_{4}(aq)-->CaSO_{4}(s)+2NaCl(aq)

Mass of each reactant per mole:

(1 * Ca + 2 * Cl)=(1*40.08g/mol) + (2*35.45g/mol)=110.98g/mol

(2*Na)+(1*S)+(4*O)=(2*22.99g/mol)+(1*32.07g/mol)+(4*16.00g/mol)=142.04g/mol

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

Mass of each product per mole:

(1*Ca)+(1*S)+(4*O)=(1*40.08g/mol)+(1*32.06g/mol)+(4*16.00g/mol)=136.14g/mol

(2*Na)+(2*Cl)=(2*22.99g/mol)+(2*35.45g/mol)=116.88g/mol

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.

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answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.