fundamental definitions in chemistry.doc

Fundamental Definitions in Chemistry

Mole A mole is a number that is equal to the number of carbon atoms found

in exactly 12 grams of carbon-12. This number is equal to 6.0 x 1023 and is given a special name Avogadro’s number. The Avogadro’s number has unit mole-( per mole)

number of moles mass mass of 1 mole number of moles number of particles

6.0 x 1023

Relative atomic mass- Ar

The relative atomic mass of an atom is the number of times the atomis heavier than one twelfth of an atom of carbon-12

the relative atomic mass of one atom mass of atom 1/12 mass of 1 carbon-12 atom

Relative atomic mass of an element The relative atomic mass of an element is the average mass of one atom of the element

compared with 1/12th mass of one atom of carbon.12 the relative atomic the average mass of 1 atom of the element mass of an element 1/12 mass of 1 carbon-12 atom

Relative molecular mass- Mr

the relative molecular mass mass of one molecule 1/12 mass of 1 carbon-12 atom Molecular mass is equal to sum of the atomic masses

Molecular mass of carbon dioxide is (CO2) = 12+ 16+ 16 = 44 Molar mass ( mass of one mole)

The mass (in grams) of 1 mole of a substance is called its molar mass. The mass of 1 mole of atoms is equal to its relative atomic mass in grams. The mass of 1 mole of molecules is equal to its relative molecular mass in grams. The mass of 1 mole of formula units of ionic compound is equal to its relative formula mass in grams. number of moles mass of substance molar mass of substance

Molar mass has unit mole/gFormula mass is equal to sum of the atomic masses

Empirical formulaThe empirical formula shows the simplest number ratio of the different

types of atoms in a compound.

Molecular formula The molecular formula shows the actual number and kinds of atoms

present in a compound Molecular formula mass = n(empirical formula mass)

n = molecular mass empirical formula mass

The Periodic Table consists symbol of the elements arranged by increasing the atomic number strictly.

Molecular mass is equal to sum of the atomic masses

1

Molecular mass of sulphure dioxide is (SO2) = 32+ 16+ 16 = 64Find the molecular masses of the following molecules.

1) CH3CH2CH3,propane 6) C12H22O11,sucrose

2) C3H6O3 lactic acid 7) C6H8O7 citric acid

3) C9H8O4 aspirin for mild pain 8) C8H9O2N paracetamol for headaches

4)C8H18 petrol 9) CO(NH2)2 urea as fertilizer

5) H2C6H6O6 vitamin C 10) H2C2O4 oxalic acid

Substance exists as an atoms, the amount can find

number of moles of atoms mass relative atomic mass number of moles of atoms number of atoms

6.0 x 1023

Find the amount of following atoms.

1) 69 g of sodium 2) 48 g of O (oxygen atoms) 3) 96 g of sculpture

4) 93 g of phosphorous 5) 112 g of sodium 6) 71 g of chlorine atoms

Substance exists as molecules, the amount can find

number of moles of molecules mass relative molecular mass

number of moles of molecules number of molecules 6.0 x 1023

Find the amount of following molecules.

1) 142 g of Cl2 2) 128 g of O2 3) 88 g of CO2 4) 64 g of CH4

5) 36 g of H2O 6) 46 g of NO2 7) 88 g of C3H8 –propane

The amount of atoms or molecules can find

Number of moles X 6.0 x 1023 = number of molecules

Number of moles X 6.0 x 1023 = number of atoms

Calculate the molecules and atoms present on the above substances

156 g benzene C6H6 contains how many moles? and how many atoms?

Number of moles = mass of benzene = 156/ 78 = 2 mol

formula mass

so number of molecules = moles x 6.0 x 1023

so number of molecules = 2X 6.0 x 1023 = 12 x 1023

1 molecule of benzene consist atoms are =1212 x 1023 molecule of benzene consist atoms are = 12 atoms x12 x 1023 molecules 1 molecule

= 144 x 1023 atoms

Substance exists as an ionic compound, the amount of formula units can find

number of moles of formula units mass relative formula mass

number of moles of formula units number of formula units 6.0 x 1023

Find the amount of following ionic compounds.

1) 117 g of sodium chloride 4) 466 g of barium sulphate

2) 318 g of sodium carbonate 5) 120 g 0f sodium hydroxide

3) 112 g of potassium hydroxide 6) 342 g of barium hydroxide

(C=12,O=16,N=14,H=1,Fe+56,Zn=65,Cu=64,Pb=207,Ba=137,Sr=88,Co=59,Ca=40,Mg=24,P=31,S=32,Al=27)

2

At room temperature and pressure 1 mole of any gas has 24 dm3 ( 24000 cm3 ) volume. Molar volume

Molar volume 24 mol/ dm3 = 24000 mol/cm3

Calculate the volume of following.

a) 8 g of CH4 d) 0.16 g of oxygen g) 0.22 g of carbon dioxide

b) 0.002 g of hydrogen e) 0.28 g of nitrogen h) 0.71 g of chlorine

c) 160 g of methane f) 280 g of nitrogen i) 440 g of carbon dioxide

Calculate the masses of following

a) 240 dm3 of carbon dioxide b) 240 cm3 of oxygen c) 2400 cm3 of hydrogen

d) 2400 cm3 of nitrogen e) 240 cm3 of chlorine f) 240 cm3 of methane

Mass volume calculations

a) According to following equation reaction has done

Mg(s) + 2HNO3(aq) Mg(NO3)2(aq) + H2(g)

2400 cm3 of hydrogen was collected, What is the mass of Mg reacted at R.T.P

What is the volume of 0.5 mol/dm3 HNO3(aq) which react with Mg

b) According to following equation reaction has done

Cu2S(s) + 2O2(g) 2CuO(s) + SO2(g)

2400 cm3 of sulphure dioxide was collected, What is the mass of Cu2S reacted at R.T.P

c) According to following equation reaction has done

Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g)

240 cm3 of carbon dioxide was collected, What is the mass of Fe2O3 reacted at R.T.P

d) According to following equation reaction has done

Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)

24 cm3 of hydrogen was collected, What is the mass of Zn reacted at R.T.P

What is the volume of 0.1 mol/dm3 H2SO4 (aq) which react with Zn

e) According to following equation reaction has done

Cu(s) + 2H2SO4(aq) CuSO4(aq) + SO2(g) +2H2O(l)

4800 cm3 of sulphure dioxide was collected, What is the mass of Cu reacted at R.T.P

What is the volume of 0.5 mol/dm3 H2SO4 (aq) which react with Cu

f) According to following equation lead nitrate was heated

2Pb(NO3)2(s) 2PbO (s) + 4NO2(g) + O2(g)

480 cm3 of oxygen was collected, What is the mass of Pb(NO3)2 reacted at R.T.P

g) According to following equation calcium carbonate was heated.

CaCO3 CaO(s) + CO2 (g)

240 cm3 of carbon dioxide was collected, What is the mass of CaCO3 reacted at R.T.P

h) According to following equation reaction has done

MgCO3 (s) + 2HNO3(aq) Mg(NO3)2(aq) + H2O(l) + CO2(g)

24 cm3 of carbon dioxide was collected, What is the mass of MgCO3 reacted at R.T.P

What is the volume of 0.25 mol/dm3 HNO3(aq) which react with MgCO3


3

i) According to following equation reaction has done

CaCO3(s) +2HNO3(aq) Ca(NO3)2(aq) + H2O(l) + CO2(g)

2400 cm3 of carbon dioxide was collected, What is the mass of CaCO3 reacted at R.T.P

What is the volume of 0.1mol/dm3 HNO3(aq) which react with CaCO3

j) According to following equation aluminium reacted with HCl

2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g)

4800 cm3 of hydrogen was collected, What is the mass of Al reacted at R.T.P

What is the volume of 0.05 mol/dm3 HCl (aq) which react with Al

k) According to following equation aluminum carbonate was heated

Al2(CO3)3(s) Al2O3(s) + 3CO2 (g)

480 cm3 of carbon dioxide was collected, What is the mass of Al2(CO3)3 reacted at R.T.P

Percentage composition

a) 0.41g of copper wire react with 0.20 mol/dm3 HNO3 acid according to following equation and collect

240 cm3 of NO2 gas at R.T.P

Cu(s) + 4HNO3(aq) Cu(NO3)2(aq) + 2H2O(l) + 2NO2(g)

1) What is the amount of NO2(g) in mol?

2) What is the amount of Cu in mole?

3) What is the mass of Cu?

4) What is the Cu% in copper wire?

5) What is the required volume of 0.20 mol/dm3 HNO3 ?

6) What is the mass of Cu(NO3)2

b) 0.1g of zinc alloy react with 0.50 mol/dm3 HCl acid according to following equation and collect

24 cm3 of H2 gas at R.T.P

Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)

1) What is the amount of H2(g) in mol?

2) What is the amount of Zn in mole?

3) What is the mass of Zn ?

4) What is the Zn% in zinc alloy?

5) What is the required volume of 0.50 mol/dm3 HCl ?

6) What is the mass of ZnCl2

c) 0.19g of magnesium wire react with 0.50 mol/dm3 H2SO4 acid according to following equation and

collect 120 cm3 of H2 gas at R.T.P

Mg(s) + H2SO4(aq) MgSO4(aq) + H2(g)


2) What is the amount of Mg in mole?

3) What is the mass of Mg?

4) What is the Mg% in magnesium wire?

5) What is the required volume of 0.50 mol/dm3 H2SO4 ?

6) What is the mass of MgSO4


4

d) 0.41g of marble react with 0.40 mol/dm3 HCl acid according to following equation and collect

80 cm3 of CO2 gas at R.T.P

CaCO3 (s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g)

1) What is the amount of CO2(g) in mol?

2) What is the amount of CaCO3 in mole?

3) What is the mass of CaCO3?

4) What is the CaCO3 % in marble?

5) What is the required volume of 040 mol/dm3 HCl ?

6) What is the mass of CaCl2

e) 7.5g of metal calcium alloy react with H2O (aq) according to following equation and collect

1600 cm3 of H2 gas at R.T.P

Ca(s) + 2H2O (aq) Ca(OH)2(aq) + 2H2(g)


2) What is the amount of Ca in mole?

3) What is the mass of Ca?

4) What is the Ca% in an alloy?

5) What is the mass of Ca(OH)2?

f) 1.4g of magnesium cube react with steam according to following equation and collect

1200cm3 of H2 gas at R.T.P

Mg(s) + H2O(g) MgO(s) + H2(g)




4) What is the Mg% in magnesium cube?

5) What is the mass of MgO ?

g) 0.5g of egg shells react with 0.30 mol/dm3 HNO3 acid according to following equation and collect

120 cm3 of CO2 gas at R.T.P

MgCO3(s) + 2HNO3(aq) Mg(NO3)2(aq) + H2O(l) + CO2(g)




4) What is the Mg% in egg shells?


6) What is the mass of Mg(NO3)2

h) 3.21g of iron wire react with 0.40 mol/dm3 HCl acid according to following equation and collect

1200cm3 of H2 gas at R.T.P

Fe(s) + 2HCl(aq) FeCl2(aq) + H2(g)


2) What is the amount of Fe in mole?

5

3) What is the mass of Fe?

4) What is the Fe% in iron wire?


6) What is the mass of FeCl2

i) 0.30g of aluminium wire react with 0.25 mol/dm3 HCl acid according to following equation and

collect 80 cm3 of H2 gas at R.T.P

2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2 (g)


2) What is the amount of Al in mole?

3) What is the mass of Al?

4) What is the Al% in aluminium wire?


6) What is the mass of AlCl3

j) 2.30g of silver compound react with 0.25 mol/dm3 HNO3 acid according to following equation and

collect 160cm3 of CO2 gas at R.T.P

Ag2CO3(s) + 2HNO3(aq) 2AgNO3 (aq) + H2O(l) + CO2(g)


2) What is the amount of Ag2CO3 in mole?

3) What is the mass of Ag2CO3?

4) What is the Ag2CO3% in silver compound?


6) What is the mass of AgNO3

k) 23 g of lead compound react with 0.5 mol/dm3 HNO3 acid according to following equation and

collect 1600cm3 of CO2 gas at R.T.P

PbCO3(s) + 2HNO3(aq) Pb(NO3) 2(aq) + H2O(l) + CO2(g)


2) What is the amount of PbCO3 in mole?

3) What is the mass of PbCO3?

4) What is the PbCO3% in lead compound?

5) What is the required volume of 0. 5 mol/dm3 HNO3 ?

6) What is the mass of Pb(NO3) 2?

l) 170g of silver wire react with 0.25 mol/dm3 HNO3 acid according to following equation and collect

16000 cm3 of H2S gas at R.T.P

Ag2S(s) + 2HNO3(aq) 2AgNO3 (aq) + H2S(g)

1) What is the amount of H2S (g) in mol?

2) What is the amount of Ag2S in mole?

3) What is the mass of Ag2S?

4) What is the Ag2S % in silver wire?


6) What is the mass of AgNO3?


6

Crystallization of water

1) A student was given some hydrated sodium carbonate crystals,Na2CO3.XH2O,where X is a whole

number. They were placed in a previously weighed container, which was reweighed.

mass of container + sodium carbonate crystals = 9.87 g

mass of container = 5.83 g

a) Calculate the mass of sodium carbonate crystals used in the experiment

The container and crystals were heated to remove the water of crystallization and then reweighed.

This process was repeated until there was no further change in mass.

b) Describe the appearance of the sodium carbonate crystals after heating.

mass of container + anhydrous sodium carbonate = 7.35 g

c) i) Calculate the mass of sodium carbonate which remained after heating.

ii) Calculate the mass of water which lost from the crystals.

d) Calculate the relative formula mass of sodium carbonate,Na2CO3, and the relative molecular mass

of water

e)Using your answers to c) and d) calculate

i) the number of moles of sodium carbonate which remained after heating,

ii) the number of moles of water which were lost on heating.

f) Using your answer to e) calculate the value of X in the formula Na2CO3XH2O

2) A student was given some hydrated copper(II) sulphate crystals,CuSO4.XH2O,where X is a whole


mass of container + hydrated copper(II) sulphate = 9.50 g


a) Calculate the mass of hydrated copper(II) sulphate crystals used in the experiment



b) Describe the appearance of the copper(II) sulphate after heating.

mass of container + anhydrous copper(II) sulphate = 9.05 g

c) i) Calculate the mass of copper(II) sulphate which remained after heating.


d) Calculate the relative formula mass of copper(II) sulphate, CuSO4, and the relative molecular mass

of water


i) the number of moles of copper(II) sulphate which remained after heating,


f) Using your answer to e) calculate the value of X in the formula CuSO4.XH2O

3) A student was given some hydrated cobalt(II)chloride crystals,CoCl2.XH2O,where X is a whole


mass of container + hydrated cobalt(II)chloride crystals = 9.716 g


a) Calculate the mass of hydrated cobalt(II)chloride crystals used in the experiment.

7



b) Describe the appearance of the cobalt(II)chloride after heating.

mass of container + anhydrous cobalt(II)chloride = 7.916g

c) i) Calculate the mass of cobalt(II)chloride which remained after heating.


d) Calculate the relative formula mass of cobalt(II)chloride , CoCl2, and the relative molecular mass of

water


i) the number of moles of cobalt(II)chloride which remained after heating,


f) Using your answer to e) calculate the value of X in the formula CoCl2.XH2O

4) A student was given some hydrated iron(II)sulphate crystals,FeSO4.XH2O,where X is a whole


mass of container + hydrated iron(II)sulphate crystals = 9.85 g


a) Calculate the mass of hydrated iron(II)sulphate crystals used in the experiment



b) Describe the appearance of the iron(II)sulphate after heating.

mass of container + iron(II) sulphate = 8.77 g

c) i) Calculate the mass of iron(II)sulphate which remained after heating.


d) Calculate the relative formula mass of hydrated iron(II)sulphate , FeSO4, and the relative molecular

mass of water


i) The number of moles of iron(II)sulphate which remained after heating,

ii) The number of moles of water which were lost on heating.

f) Using your answer to e) calculate the value of X in the formula FeSO4.XH2O

5) A student was given some hydrated magnesium crystals,MgSO4.XH2O,where X is a whole number.

They were placed in a previously weighed container, which was reweighed.

mass of container + hydrated magnesium crystals = 25.55g


a) Calculate the mass of hydrated magnesium crystals used in the experiment



b) Describe the appearance of the magnesium after heating.

mass of container + anhydrous sodium carbonate = 19.25 g

c) i) Calculate the mass of magnesium which remained after heating.


d) Calculate the relative formula mass of magnesium, MgSO4, and the relative molecular mass of

water

8


i) the number of moles of magnesium which remained after heating,


f) Using your answer to e) calculate the value of X in the formula MgSO4.XH2O

6) A student was given some hydrated calcium sulphate crystals,CaSO4.XH2O,where X is a whole


mass of container + calcium sulphate crystals = 24.31 g


a) Calculate the mass of calcium sulphate crystals used in the experiment



b) Describe the appearance of the calcium sulphate after heating.

mass of container + anhydrous calcium sulphate = 21.91 g

c) i) Calculate the mass of calcium sulphate which remained after heating.


d) Calculate the relative formula mass of calcium sulphate, CaSO4, and the relative molecular mass of

water


i) the number of moles of calcium sulphate which remained after heating,


f) Using your answer to e) calculate the value of X in the formula CaSO4.XH2O

Avogadrow’s LawAt the same temperature and same pressure, equal volumes of

gases has equal molecules or moles.

At the same temperature and same pressure, equal molecules or

moles of gases has an equal volume.

1 CH4(g) + 2O2(g) CO2(g) + 2H2O(l)

At R.T.P methane burns according to the above equation.

a. What is the volume of oxygen that react with 32g of methane.

b. What is the number of molecules of CH4 and O2 that formed 12 dm3 CO2

c. What is the number of molecules of methane which react with 2400 cm3 of O2

2 Find the ratio of the number of molecules in 4.0g of hydrogen to the number of molecules in 6.0

dm3 of oxygen at R.T.P.

3 A sample of nitrogen gas contains the same number of atoms as found in 4.25 g of ammonia gas.

What is the mass of the sample of nitrogen gas?

A 3.50 g B 7.00g C 14.0g D 28.0g

4 Methane reacts with steam to form hydrogen and carbon monoxide according to the following

equation;

CH4(g) + H2O(g) CO (g) + 3H2 (g)

What total volume of gaseous products can be obtained from 100 cm3 of methane?

9

( All gas volumes are measured at the same temperature and pressure)

A 500 cm3 B 400 cm3 C 300 cm3 D 100 cm3

5 In the experiment 264g of strontium reacts with 213 g of chlorine

What is the formula of strontium chloride?

A SrCl B SrCl2 C SrCl3 D Sr2Cl

6 A sample of an ester contains 0.18g of carbon, 0.03g of hydrogen and 0.08g of oxygen.

The relative molecular mass of the ester is 116.

Find both the empirical and molecular formulae of this ester.

7 2 dm3 of aqueous sodium hydroxide of concentration 5 mol/dm3 were required for an

Experiment.

How many moles of sodium hydroxide were needed to make up this solution?

A 2.5 B 5 C 7 D 10

8 An 8g of sample of oxygen atoms contains the same number of atoms as 16g of

Element X.

What is the relative atomic mass, Ar, of X?

A. 4 B. 8 C. 16 D. 32

9 When a 1.20g sample of graphite is completely burnt in oxygen, 4.40g of carbon

dioxide are produced. What mass of carbon dioxide is made when a 1.20g sample

of diamond is completely burnt in oxygen?

10 What is the ratio of the volume of 2 g of hydrogen to the volume of 16 g of methane, both at

A 1 to 1 B 1 to 2 C 1 to 8 D 2 to 1

11 What is the mass of aluminium in 204 g of aluminium oxide, Al2O3?

A 26 g B 27 g C 54 g D 108 g

12 A sample of a compound of iron is analysed. The sample contains 0.547 g of potassium,

0.195 g of iron, 0.252 g of carbon and 0.294 g of nitrogen.

Calculate the empirical formula of this compound.

13 How many moles per dm3 of gaseous carbon dioxide are there if 4.4 g occupies 500 cm3?

A 0.1 mol / dm3 B 0.2 mol / dm3 C 2.2 mol / dm3 D 8.8 mol / dm3

14 Aluminium sulphate can be obtained as shown in the equation.

2Al(OH)3 + 3H2SO4 Al2(SO4)3 + 6H2O

How many moles of sulphuric acid are needed to produce 0.5 mol of aluminium sulphate?

A 0.5 B 1.0 C 1.5 D 3.0

15 Ethene can also be converted into a compound that contains carbon, hydrogen and

10

oxygen. A sample of the compound was analysed and found to contain 0.72 g of

carbon, 0.18 g of hydrogen and 0.96 g of oxygen.

Show that the empirical formula of the compound is CH3O.

16 Sodium carbonate has the formula NayCO3. The molar mass, M, of the compound

is 106. What is the value of y and hence what is the formula of the compound.

17 A sample of iron sulphide contains 5.373 g of iron and 4.627 g sulphur. What is the empirical

formula of the compound?

18 A compound has the composition by mass: 29.4% calcium, 23.5% sulphur and 47.1%

oxygen. Find the empirical formula.

19 The spot turns black when palladium(II) chloride reacts with carbon monoxide to form

palladium metal.

PdCl 2(s) + + CO(g) Pd(s) + 2HCl (g) + CO2(g)

(i) Complete the equation by writing the formula of the missing reactant in the box.

20 Ammonium sulphate can be made by reacting aqueous ammonia with dilute sulphuric

acid.

2NH3(aq) + H2SO4(aq) (NH4)2SO4(aq)

Calculate the mass of ammonium sulphate that can be made from 51 g ammonia.

21 The relative molecular mass, Mr, of copper(II) sulphate, CuSO4, is 160.

The relative molecular mass, Mr, of water is 18.

What is the percentage by mass of water in copper(II) sulphate crystals, CuSO4.5H2O?

A 18 x100 B 5 X 18 X 100 C 18 X 100 D 5 X 18 X 100

160 160 + 18 160 + 18 160 + (5 x 18)

22 124 g of phosphorus vapour has the same volume as 71 g of chlorine gas at the

same temperature and pressure. What is the formula of a molecule of phosphorus?

A P8 B P4 C P2 D P

23 Analysis of an organic acid isolated from red ants shows that it contains 0.060 g of carbon,

0.010g of hydrogen and 0.16 g of oxygen.

Calculate the empirical formula for this acid.

24 A white powder is analysed and found to contain 43.64 g of phosphorus and 56.36 g of oxygen.

Calculate the empirical formula of the compound

25 Vitamin C contains 40.92% carbon , 4.58 hydrogen ,and 54.5% oxygen by mass.

Calculate the empirical formula of vitamin C

11

The molecular mass of vitamin C is 87. calculate the molecular formula

26 An anaesthetic compound is found to contain the elements carbon, hydrogen and oxygen.

The percentage by mass of these elements are given below;

Carbon 64.9%

Hydrogen 13.5%

Oxygen 21.6%

One mole compound has a mass of 74 g. Calculate the empirical formula and molecular formula.

27 What is the mass of magnesium which completely reacts with 250 cm3 of 1.0 mol /dm3

sulphuric acid?

A 6g B 12 g C 48 g D 96 g

24 A volume of ethane, C2H6, at r.t.p. has a mass of 20 g.

What is the mass of an equal volume of propene, C3H6, at r.t.p.?

A 20 g B 21 g C 28 g D 42 g

28 A sample of a hydrocarbon contains 0.240 g of carbon and 0.050 g of hydrogen.

Calculate the empirical formula of this hydrocarbon.

26 What is the mass of magnesium which completely reacts with 250 cm3 of 1.0 mol /dm3 sulphuric

acid?

A 6g B 12 g C 48 g D 96 g

29 A volume of ethane, C2H6, at r.t.p. has a mass of 20 g.

What is the mass of an equal volume of propene, C3H6, at r.t.p.?

A 20 g B 21 g C 28 g D 42 g

30 Which sulphide contains the greatest mass of sulphur in a 10 g sample?

31 When 20 cm3 of a gaseous alkene burns in an excess of oxygen, 60 cm3 of carbon dioxide are formed. Both volumes are measured at r.t.p. What is the formula of the alkene?A C3H6 C C6H12 B C3H8 D C6H14

32 Calculate N percentage of the following fertilizersa) NH4NO3 ammonium nitrate b) (NH4)2SO4 ammonium sulphate c) CO(NH2)2 urea d) KNO3 potassium nitrate e) (NH4)2HPO4 diammonium hydrogen phosphate f) (NH4)3PO4 ammonium phosphate


sulphide formula mass of one mole/g

ABCD

NiSFeS2

MoS2

PbS

90120160239

12

33 The equation for the burning of hydrogen in oxygen is shown below. 2H2(g) + O2(g) 2H2O(g) Which information does this equation give about the reaction?A 36 g of steam can be obtained from 16 g of oxygen.B 2 g of hydrogen combine with 1 g of oxygen.C 2 mol of steam can be obtained from 1 mol of oxygen.D 2 atoms of hydrogen combine with 2 atoms of oxygen.

34 In an experiment to find the formula of the oxide formed of the element M, 5.5 g of M was

burnt in oxygen. The mass of the oxide was 8.7 g.[ Ar; M, 55; O, 16.]

What is the formula of the metal oxide ?

A) MO B) M2O C) MO2 D) MO3

35 All ammonium salts on heating with sodium hydroxide produce ammonia gas.

From which ammonium salt can the greatest mass of ammonia be obtained?

A 0.5 mol (NH4)3PO4

B 0.5 mol(NH4)2SO4

C 1.0 mol NH4Cl

D 1.0 mol NH4NO3

35 Substance has the highest percentage by mass of nitrogen?

A NH4NO3 Mr = 80

B (NH4)2SO4 Mr = 132

C CO(NH2)2 Mr = 60

D (NH4)3PO4 Mr = 149

36 A 10 cm3 sample of gaseous hydrocarbon is completely burnt in oxygen. The total volume of the

products is 70cm3

Which equation represent the combustion of the hydrocarbon?

A CH4(g) + 2O2(g) CO2(g) + 2H2O(g)

B C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(g)

C C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g)

D 2C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(g)


13

fundamental definitions in chemistry.doc

Documents

Transcript of fundamental definitions in chemistry.doc