Quantitative Chemistry

Question 1

Conservation of mass

Answer 1

No atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants

Question 2

Ionic compounds

Answer 2

Ionic compounds are formed when metals react with nonmetals

metals form positive ions and most non-metals form negative ions

Question 3

Formula of ionic compounds

Answer 3

In an ionic compound, the charges on the ions have to cancel out to leave an overall charge of zero

Question 4

What is relative atomic mass Ar

Answer 4

The relative atomic mass of an element is the average mass of the isotopes of that element weighed to take into account the abundance of each isotope

Question 5

What is relative formula mass Mr

Answer 5

The relative formula mass of a compound is the sum of the relative atomic masses of atoms in the numbers shown in the formula

Question 6

What dose a mole =

Answer 6

6.02x10(23)

Question 7

moles equation for calculating number of moles in an element

Answer 7

Number of moles = mass (g) / relative atomic mass Ar

Question 8

Moles equation for calculating the number of moles in a compound

Answer 8

Number of moles = mass (g) / relative formula mass Mr

Question 9

Concentration equation

Answer 9

Concentration (g/dm3) = mass (g) / volume (dm3)