3. Quantitative chemistry

Question 1

What is the conservation of mass?

Answer 1

In a chemical reaction, atoms are not created or destroyed so total mass remains the same throughout

Question 2

What is relative formula mass?

Answer 2

The sum of the relative atomic masses of each atom in a substance

Question 3

What are the four state symbols and what do they stand for?

Answer 3

(s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous solution

Question 4

How can you tell when a symbol equation is balanced?

Answer 4

The number of atoms of each element is the same on both sides

Question 5

What is the unit for concentration?

Answer 5

g/dm3

Question 6

What formula is used to calculate concentration from mass and volume?

Answer 6

Concentration = mass/volume

Question 7

How do you convert a volume reading in cm3 to dm3?

Answer 7

Divide by 1000

Question 8

How can concentration be calculated in mol/dm3?

Answer 8

Concentration = moles of solute/volume

Question 9

Give the value for Avogadro’s constant

Answer 9

6.02x10^23 particles

Question 10

What formula is used to calculate the mass of a substance from the number of moles and the Mr?

Answer 10

Mass = Mr x moles