1 - Stoichiometry

Question 1

atom economy

Answer 1

a measure of the amount of starting materials that become useful products.

Question 2

chemical element

Answer 2

a neutral substance that cannot be broken down into simpler substances using chemical methods

Question 3

compound

Answer 3

a pure substance formed when two ore more chemical elements are chemically bonded together in fixed ratios

Question 4

exothermic

Answer 4

release energy

Question 5

endothermic

Answer 5

absorb/ require energy

Question 6

sublimation

Answer 6

changing from solid to gas

Question 7

deposition

Answer 7

changing from gas to solid

Question 8

pure substance

Answer 8

an element or compound that has a definite and constant composition

Question 9

mixture

Answer 9

a physical combination of pure substances which has no definite or constant composition e.g. homogeneous, heterogeneous. It can be separated into its pure components through filtration (seperate from liquid or gas), distillation (using different boiling points) and various forms of chromatography.

Question 10

homogeneous mixtures

Answer 10

all the components are in the same phase

Question 11

heterogeneous

Answer 11

the components are is different phases

Question 12

mole

Answer 12

specific amount of a substance

Question 13

Avogadro’s constant

Answer 13

is the number of atoms in 12g of Carbon-12

Question 14

empirical formula

Answer 14

shows the simplest whole number ratio of atoms of each element in a particle of the substance

Question 15

molecular formula

Answer 15

shows the actual number of atoms of each element in a molecule of the substance

Question 16

theoretical yield

Answer 16

maximum amount of a product that could be formed according to the balanced equation

Question 17

experimental yield

Answer 17

actual amount of product obtained when the experiment is performed

Question 18

percentage yield

Answer 18

experimental yield divided by theoretical yield as a percentage