Moles

Question 1

what is avogadro constant

Answer 1

number of particles in 1 mole. 6.02x10(23)

Question 2

what is the formula to work out the mass

Answer 2

n x mr

Question 3

Define empirical formula

Answer 3

simplest whole number ratio of atoms of each element present in a compound

Question 4

Define molecular formula

Answer 4

the actual number and type of atoms of each element in a molecule

Question 5

what is a hydrated salt

Answer 5

when water is part of its crystalline structure

Question 6

name the steps for an experiment to make an anhydrous salt

Answer 6

1. weigh an empty crucible
2. use a pipe clay triangle to support crucible containing salt on a tripod. Gently heat for 1 minute and strongly for 3.
3. Leave to cool then weigh anhydrous salt.

Question 7

how can you ensure all water is gone from salt

Answer 7

the salts will be different colours. Repeatedly heat the compounds.

Question 8

what is stoichiometry

Answer 8

relationship between the amounts of reactants and products in a chemical reaction

Question 9

what is the gas volume equation

Answer 9

v=nx24

Question 10

what is the concentration equation

Answer 10

n
- = c
v

Question 11

what is the ideal gas equation

Answer 11

PV=nRT

Question 12

how do you convert from degrees to K

Answer 12

+273

Question 13

how do you convert kPa to Pa

Answer 13

x10(3)

Question 14

what does R equal

Answer 14

8.314Jmo(-1)K(-1)

Question 15

how can you convert cm(3) to m(3)

Answer 15

x10(-6)

Question 16

what properties does the ideal gas have

Answer 16

random motion (HT), elastic collision, negligible size (LP) and no intermolecular forces (HT)

Question 17

what is the atom economy formula

Answer 17

Mr of desired product
————————————– x100
sum total of all Mr products

Question 18

what does a high atom economy lead to

Answer 18

less waste products and more sustainable

Question 19

how can you increase atom economy

Answer 19

use a different reaction with a higher atom economy or find a use for the unwanted product

Question 20

what is the % yield formula

Answer 20

amount of product you actually make
——————————————————- x100
amount you should theoretically make

Question 21

what can you do to increase % yield

Answer 21

most efficient conditions and apparatus

Question 22

outline a method to dilute a solution

Answer 22

1. weigh out solid using mass balance on a weigh boat
2. add water (less than volume needed)
3. stir with a stirring rod until everything is dissolved (transparent)
4. use a filter funnel to pour the solution into a volumetric flask
5. rinse off stirring rod, weigh boat and beaker into volumetric flask
6. add more distilled water until the bottom of the meniscus touches the line
7. put the lid on and invert the solution to ensure solid is mixed throughout.

Question 23

how can you calculate the concentration of a diluted solution

Answer 23

divide volume of stock solution used over final volume of diluted solution. Multiply this by the concentration of stock solution.

Question 24

what is the solubility of carbonates and hydroxides

Answer 24

insoluble except for sodium potassium and ammonium

Question 25

what is the solubility of nitrates

Answer 25

soluble

Question 26

what is the solubility of chlorides

Answer 26

soluble except silver and lead chloride

Question 27

what is the solubility of sulfates

Answer 27

soluble except lead, barium and calcium sulfate

Question 28

what is the solubility of carbonates and hydroxides

Answer 28

insoluble except sodium, potassium and ammonium