Module 2 inorganic

Question 1

What is an empirical formula?

Answer 1

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

Question 2

Define oxidation and reduction in terms of electron transfer.

Answer 2

Oxidation is loss of electrons and reduction is gain of electrons. (OILRIG)

Question 3

How many N atoms are in 5 moles of N2?

Answer 3

2 x 5 x 6.02x10^23 = 6.02X10^24

Question 4

Define relative isotopic mass

Answer 4

The mass on an isotope compared with 1/12th the mass of an atom of carbon-12.

Question 5

Give the formulae - including charge- of these ions: ammonium, hydroxide, carbonate, phosphate

Answer 5

NH+, OH-, CO3 2-, PO4 3-

Question 6

How are cm3 converted to dm3?

Answer 6

Divide by 1000

Question 7

Work out the oxidation number of S in H2SO4

Answer 7

+6 - H is 2x+1 and O is 4x-2, so for the whole number molecules to be 0, S must be +6

Question 8

What colour is phenolphthalein in acid and alkali?

Answer 8

Colourless in acid, purple/pink in alkali

Question 9

What is the oxidation number of any uncombined element?

Answer 9

Zero

Question 10

What is the usual oxidation number of hydrogen in a compound and the exception?

Answer 10

+1 usually; -1 in metal hydrides

Question 10

Name the three sub-atomic particles and give their locations in the atom

Answer 10

Protons and neutrons in the nucleus; electrons in the shells around the nucleus.

Question 10

Give the charges on ions of these atoms: Ag, Cu(II) , PO4, CO3 and Zn

Answer 10

Ag+ ,Cu2+ ,Zn2+, PO4 3- , CO3 2-

Question 10

Which technique allows the measurement of isotopic masses?

Answer 10

Mass spectrometry

Question 11

When zinc reacts with HCL acid to make zinc chloride and hydrogen gas, which element is oxidised and which is reduced?

Answer 11

Zn is oxidised from 0 to +2 and hydrogen is reduced from +1 to 0

Question 12

Give the formulae of sodium nitride and sodium nitrate.

Answer 12

Na3N and NaNO3

Question 13

What is the oxidation number of N in nitrate (V), NO3-

Answer 13

+5

Question 14

How many protons, neutrons and electrons does a Cl- ion have? Cl-35

Answer 14

p= 17 n= 18 e= 18

Question 15

When heating to remove water of crystallisation , how can you be sure all of the water has gone?

Answer 15

Reheat and reweigh until constant mass is reached.

Question 16

Define isotopes

Answer 16

Atoms of the same element with different numbers of neutrons and different masses.

Question 17

A sample of chlorine is 75.78% chlorine-35 and 24.22% chlorine-37. Calculate RAM

Answer 17

(75.78x35) + (24.22x37) / 100 = 35.48 to 2 dp

Question 18

What is the Avogadro constant?

Answer 18

The number of particles in a mole , 6.02x10^23

Question 18

What does R stand for in the ideal gas equation?

Answer 18

The gas constant, 8.314JK-1mol-1

Question 19

How can you convert concentration in mol dm-3 to units of g dm-3?

Answer 19

Multiply by the Mr of the solute

Question 20

What is a molecular formula?

Answer 20

The formula that shows the actual number of atoms of each element in a molecules.

Question 21

How would you describe what molar mass is?

Answer 21

The mass of a substance per mole (units g mol-1)

Question 22

How is atom economy calculated?

Answer 22

(Mr or mass of desired product/ Mr or mass of all products ) x 100

Question 23

What is a mole?

Answer 23

An amount of substance containing the Avogadro number of particles

Question 24

How do you convert cm3 into m3?

Answer 24

Divide by 10^6

Question 25

What is the equation that links amount in moles, concentration and volume of solution?

Answer 25

concentration (mol dm-3) = amount (mol) / vol (dm3)

Question 26

When one reactant is in excess, the other is completely used up- this reactant is called the...

Answer 26

Limiting reagent

Question 27

What are the units for each thing in the pV=nRT equation?

Answer 27

Temperature= Kelvin Pressure = pascals Volume = m3 Moles= mol R=gas constant 8.314

Question 28

How do you get from celcius to kelvin?

Answer 28

Add 273