Quantative chemistry

Question 1

What does the law of conservation of mass state?

Answer 1

That no atoms are lost or made during a chemical reaction

so the mass of the products equals the mass of the reactants

Question 2

Define relative formula mass and state its symbol

Answer 2

The sum of the relative atomic masses of the atoms in the numbers shown in the formula
Symbol: Mr

Question 3

State the formula for percentage by mass

Answer 3

Percentage by mass = (Total Ar of atoms of element / Mr of compound) x 100

Question 4

What is the value of Avogardo’s constant?

Answer 4

6.02 x 10^23 per mole

Question 5

State the equation to find number of moles

Answer 5

number of moles = mass / relative formula mass

no more room

Question 6

In a chemical reaction, why is an excess of one of the reactants usually used?

Answer 6

To ensure the reactant is completely used up

Question 7

State the unit for concentration

Answer 7

g/dm^3

Question 8

State the formula for finding the concentration of a solution

Answer 8

concentration = mass (g) / volume (dm^3)

cry more vela

Question 9

Explain how the mass of a solute of a solute is related to the concentration of the solution (assuming volume is the same)

Answer 9

The higher the mass of the solute, the higher the concentration

Question 10

Explain how the volume of a solution is related to the concentration of the solution (assuming mass of solute is the same)

Answer 10

The more the volume, the less the concentration

Question 11

Define concentration

Answer 11

The mass of solute in a given volume of solution