Stoichiometric Relationships

Question 1

What is the equation for percentage atom economy?

Answer 1

Question 2

What equation joins moles, No. of particles and Avogadro’s constant?

Answer 2

Question 3

For what kind of substances is Relative Molecular Mass (M_r) Used for?

Answer 3

Covalent Compounds

Question 4

For what kind of substances is Relative Formula Mass used for?

Answer 4

Ionic Comounds

Question 5

What equation joins moles, molar mass and mass of a substances?

Answer 5

Question 6

How is the % composition of a compiund found?

Answer 6

Question 7

What are the 3 main ways of analysing compounds for empirical formulas?

Answer 7

• Combustion Analysis (combusting and finding masses of CO₂ and H_2O
• Direct Determination (Reacting known masses of known element with a 2^nd)
• Decomposition (Decompose, usually heating, a sample with known mass and measuring the mass of compound)

Question 8

What is the equation for % yield?

Answer 8

Question 9

What is Boyles Law?

Answer 9

Pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.

Question 10

What is Charles’s Law

Answer 10

A law stating that the volume of an ideal gas at constant pressure is directly proportional to the absolute temperature

Question 11

What is Gay-Lussac’s law?

Answer 11

The pressure that a gas exerts on the sides of a container of a fixed volume is directly proportional to the temperature of the gas.

Question 12

What is Avogadro’s Law”

Answer 12

The law states that if you have two equal volume samples of a gas at the same temperature and pressure, the two samples will contain the exact same number of molecules.

Question 13

What is the combined gas law?

Answer 13

It is the combination of Boyle’ law, Charles’s Law, and Gay-Lussac’s law. The combined gas law has the following equation.

Question 14

What is the Ideal Gas Equation?

Answer 14

Question 15

Convert between cm³, dm³ and m³.

Answer 15

cm³ /1000

goes to…

dm³ /1000

goes to…

m³

Question 16

What equation joins concentration, amount of solute in moles or grams and volume of solution?

Answer 16

Question 17

What are elements?

Answer 17

Substances made up of the same atoms only - has not combined with any other atoms.

Question 18

What are compounds?

Answer 18

Sunstances made up of two or more different atoms (or ions) that have chemically bonded in a fixed ratio; but not always in molecules - we cannot use the term molecule when considering ionic compounds.

Question 19

What are mixtures?

Answer 19

Substances that are made up of two or more different atoms or ions but they are not chemically bonded together in fixed ratios. Mixtures have no fixed properties but have the properties of the componenets of the mixture.

Question 20

What is a Homogeneous mixture?

Answer 20

A mixture with a uniform composition with the same properties throughout the micture. eg. milk, soft drink, bronze

Question 21

What is a Heterogeneous mixture?

Answer 21

A mixture with no uniform composition and as a result the properties change throughout the mixture. eg. a human, unshaken salad dressing, a beach.

Question 22

What is relative isotopic mass?

Answer 22

The actual or absolute mass of a specific isotope (nuclide) of an element compared with 1/12^th of the mass of the most common carbon isotope. A relative quantity, no unit is needed.

Question 23

What equation links voume, moles and molar volume of a gas?

Answer 23