Name:
Class:
Sub.:
Chemistry
Subject Teachers:
Duration
VIII
Sec:
1 Hour (60 minutes)
Total Marks:
Roll:
50
Date:
Calculators are allowed for both Section A (must be done on MCQ sheet) & B
The Periodic Table is attached at the end of the Question Paper.
SECTION-A
Mark the correct option for the following multiple-choice questions in the MCQ sheet provided
[10 x 1.5= 15]
1. What is the relative molecular mass, Mr of CuSO 4.5H2O?
A 127
B 160
C 178
D 250
2. The equation for the burning of hydrogen in oxygen is shown.
2H2(g) + O2(g) →2H2O(g)
What does this equation indicate?
A
2 atoms of hydrogen combine with 2 atoms of oxygen.
B
2 g of hydrogen combine with 1 g of oxygen.
C
2 moles of steam can be obtained from 0.5 mole of oxygen.
D
2 moles of steam can be obtained from 1 mole of oxygen.
3. What is the concentration of a solution containing 1.0 g of sodium hydroxide in 250 cm 3 of solution?
A 0.025 mol / dm3
B 0.10 mol / dm3
C 0.25 mol / dm3
D 1.0 mol / dm3
4. 1.00dm3 of ammonia gas is passed over heated copper (II) oxide.
3CuO(s) + 2NH3 (g) → 3Cu(s) + N2(g) + 3H2O(l)
What is the volume of nitrogen formed when measured at the same temperature and pressure as the
ammonia?
A 0.25 dm3
B 0.50dm3
C 1.00dm3
D 2.00dm3
5. Using the Periodic Table for the relative atomic masses, which has the least mass?
A 0.1 mole of Silicon dioxide, SiO 2
B 0.5 mole of Oxygen, O2
C 0.5 mole of Lithium, Li
D 1 mole of ammonia, NH3
6. An element, E, forms a hydride, EH4, which contains 90.0% by mass of E.
If the relative mass of hydrogen is 1, what is the relative atomic mass of E?
A9
B 36
C 86
D 90
7. A piece of chalk has a mass of 23.0g. Chalk is impure calcium carbonate. When analysed, the chalk is
found to contain 0.226 moles of pure calcium carbonate. (Mr of CaCO 3 = 100)
What is the percentage purity of the piece of chalk?
A 0.983%
B 1.02%
C 77.0%
D 98.3%
8. 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
9. Analysis of a sample of an oxide of nitrogen gave the following data.
●
percentage by mass of nitrogen
47%
●
percentage by mass of oxygen
53%
What is the empirical formula of this oxide?
A
NO
B
NO2
C
N2O
D N2O3
10. Which contains the greatest mass of nitrogen?
A
B
C
D
0.5 moles (NH4)2SO4
1 mole NH4NO3
1.5 moles (NH4)3PO4
2 moles CO(NH2)2
Section – B
Answer the following in your answer scripts (round off your answers to 3 decimal places)
1. Define the following:
[1x5=5]
(a) Relative atomic mass (b) Molar gas volume (c) Empirical formula
(d) Avogadro’s number
(e) Mole
2. Balance the following chemical equations:
(a)
____ NH3 + ____ H2SO4 → ____ (NH4)2SO4
(b)
____ Pb(OH)2 + ____ HCl → ____ H2O + ____ PbCl2
(c)
____ AgNO3 + ____ Cu → ____ Cu(NO3)2 + ____ Ag
(d)
____ Na3PO4 + ____ KOH → ____ NaOH + ____ K3PO4
(e)
____ GaF3 + ____ Cs → ____ CsF + ____ Ga
(f)
____ Mg + ____ H2SO4 → ____ H2 + ____ MgSO4
3. How many grams are there in;
(a) 0.56 mol of Na2O
[1x6=6]
[1.5x3 =4.5]
(b) 1.12dm3 of Oxygen gas (c) 2.43 x 1022 atoms of lithium
4. How many moles are there in;
[1.5x3 =4.5]
(a) 19cm3 of Nitrogen gas (b) 1.8 x 1023 ions of Magnesium (c) 0.2g of Sulphur
5. How many particles are there in;
[1.5x3 =4.5]
(a) 0.075mol of Iron (II)Oxide (b) 100cm 3 of Iodine solution (c) 7.2g of Sodium Chloride
6. Solve the following problems showing your steps, using appropriate units.
[10.5 marks]
(a) Silver nitrate reacts with barium chloride to form silver chloride and barium nitrate. (3)
(i) Copy and balance the chemical equation.
_____ AgNO3 + ______ BaCl2 → _____ AgCl + ______Ba(NO 3)2
(ii) If 39.02 grams of barium chloride are reacted in an excess of silver nitrate,
how many particles of silver chloride are produced?
(iii) If 410.8 grams of barium nitrate are produced how many grams of silver
nitrate were reacted?
(b) Nitrogen gas is reacted with hydrogen gas to form nitrogen trihydride, also known
as ammonia.
(3)
(i) Copy and balance the chemical equation.
_____N2(g) + _____ H2(g) → _____ NH3(g)
(ii)What volume in dm3 of ammonia will be produced at r.t.p, if 80.28 grams of
hydrogen gas is reacted in an excess of nitrogen?
(iii) How many grams of hydrogen are needed to fully react 621.9 grams of
nitrogen gas?
(c) What is the empirical formula of a compound comprising 1.8% hydrogen, 56.1% sulfur,
and 42.1% oxygen? What would be the molecular formula of this compound if the molar
mass is approximately 195g/mol.
(2.5)
(d) Phosphorus reacts with bromine to form Phosphorus tribromide, if 35.0g of bromine are reacted
and 27.9 g of phosphorus tribromide is formed, then what is the yield?
2P + 3Br2 → 2PBr3
(2)