Amount of substance

Question 1

What is Avogadro’s constant

Answer 1

6.02*10^23

Question 2

What is a mole

Answer 2

The amount of substance

Question 3

1 mole of any element equals the…

Answer 3

relative atomic mass in grams

Question 4

What is molar mass

Answer 4

The mass in grams in each mole of the substance

Question 5

What is the formula that relates moles, mass and mr

Answer 5

n=m/mr

Question 6

What is molecular formula

Answer 6

The number of atoms of each element in a molecule

Question 7

What is empirical formula

Answer 7

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

Question 8

What is relative molecular mass

Answer 8

Compares the mass of a molecule with the mass of carbon 12

Question 9

In hydrated salts the water of crystallization is shown in a formula with a…

Answer 9

large dot

Question 10

What is the method for hydrated salts

Answer 10

1.Weigh an empty crucible
2.Add the hydrated salt into the weighted crucible
3.Weigh the crucible and the hydrated salt
4.Heat the crucible and contents gently for 1 minute
5.Leave the crucible to cool
6.Then weigh the crucible and anhydrous salt

Question 11

What is concentration

Answer 11

The amount of solute in moles, dissolved in each 1dm^3 of a solution

Question 12

What is the formula for concentration

Answer 12

C=n/v

Question 13

What is standard solution

Answer 13

A solution of known concentration

Question 14

What is molar gas volume

Answer 14

The volume per mole of gas molecules at a stated temperature and pressure

Question 15

What is room temperature

Answer 15

293 kelvin(20 degrees)

Question 16

What is room pressure

Answer 16

101Kpa

Question 17

what is 1 mole of gas molecules at room temp and pressure

Answer 17

24dm^3

Question 18

What is the formula for the amount in moles of a gas

Answer 18

n=volume/24

Question 19

What is the ideal gas constant

Answer 19

8.31Jmol^-1K^-1

Question 20

What is the ideal gas equation

Answer 20

Pv=nRT
p=pressure
v=volume
R=ideal gas constant
T=Temperature

Question 21

What is the method to find the relative molecular mass

Answer 21

1.Add a sample of the volatile liquid to a small syringe
2.Weigh the small syringe
3.inject the sample into a gas syringe through the self-sealing rubber cap
4.Reweigh the small syringe to find the mass of the volatile liquid
5.Place the gas syringe in a boiling water bath
6.Record the pressure of the gas produced

Question 22

What is Stoichiometry

Answer 22

The balancing numbers give the ratio of the amount(in moles) of each substance
Example:
2H2(g) + 02(g) –> 2H20(l)
2 mol 1 mol 2 mol

Question 23

What is the method to identify an unknown metal

Answer 23

1.Weigh a sample of the metal and add to the flask
2.Using a measuring cylinder add 25cm^3 1mol dm^-3 HCL to the flask and quickly replace the bung
3.Measure the maximum volume of gas in the syringe

Question 24

What is theoretical yield

Answer 24

The maximum possible amount of product

Question 25

What is the formula for percentage yield

Answer 25

percentage yield=actual yield/theoretical yield*100

Question 26

What is the limiting reactant

Answer 26

The reactant that is not in excess will be completely used up first

Question 27

What is atom economy

Answer 27

A measure of how well atoms have been utilized

Question 28

What is the formula for atom economy

Answer 28

atom economy=sum of molar masses of desired products/sum of molar masses of products * 100