Thermal stability of Group 2 compounds, and the comparison with Group 1

Question 1

Thermal stablitity is a term that indicates how

Answer 1

stable a compound is when it is heated

Question 2

thermal stability is

Answer 2

a measure of the extent to which a compound decomposes when heated

Question 3

if a compound does not decompose at all, then it is (in terms of thermal stability)

Answer 3

very thermally stable

Question 4

if a compound decomposes very much, then is is……………….thermally stable

Answer 4

not stable

Question 5

when an ionic compound such as NaCl is heated so that it melts, there is ……………………..decomposition

Answer 5

no decomposition as there is a change of state

Question 6

the three reasons which explain why Group 2 nitrates and carbonates have very different thermal stabilities from Group 1 compounds are:

Answer 6

1) the charge on a group 2 cation is double that of a group 1 cation
2) the size (ionic radius) of a group 2 cation is smaller than that of the group 1 cation in the same period
3) the nitrate (NO3-) and carbonate (CO3 2-) anions are more complex than the Cl- ion

Question 7

all of the nitrates of groups 1 and 2 are (physical escription)

Answer 7

white solids

Question 8

when Group 1 or Group 2 nitrates are heated, they……………into ………or…………… and give off……………….and/or…………
if the nitrate contains water of crystallisation, then …is also observed

Answer 8

when Group 1 or Group 2 nitrates are heated, they decompose into nitrates or oxides and give off nitrogen dioxide (brown fumes) and/or oxygen
if the nitrate contains water of crystallisation, then steam is also observed

Question 9

nitrate(V) =

nitrate(III) =

Answer 9

nitrate(V) = nitrate
nitrate(III) = nitrite

Question 10

absence of brown fumes for the decomposition of a group 1 or 2 nitarte can be shown in the word equation:

Answer 10

metal nitrate = metal nitrite + oxygen

Question 11

brown fumes for the decomposition of a group 1 or 2 nitrate can be shown byt he word equation

Answer 11

metal nitarte = metal oxide + nitrogen dioxide + oxygen

Question 12

lithium nitarte is the only group 1 metal to undrgo………….decomposition

Answer 12

greater decomposition

Question 13

all of the carbonates of the group1 and 2 elements are

Answer 13

white solids

Question 14

when carbonates of group 1 or 2 are heated they either

Answer 14

-do not decompose
or
-decompose to oxides and give off CO2

Question 15

lithium carbonate is the only group1 metal to

Answer 15

decompose when heated

Question 16

all group 2 nitartes and carbonates

Answer 16

decompose