40 Chemistry question for revision

1.

Which substance is an element? a) Air b) Steam c) Carbon d) Naphthalene

2.

What is the meaning of isotopes? a) Atoms of the same element with the same nucleon number b) Atoms of the same element with different number of neutrons c) Atoms of the different elements with different proton numbers d) Atoms of the different elements with the same nucleon number

3.

4.

5.

Which of the following statements is true for one mole of a substance? a) 1 mol of copper contain 6.02 X 1023 molecules b) 1 mol of oxygen gas contains 6.02 X 1023 atoms c) 1 mol of water contains the same number of atoms as in 12g of carbon12 d) 1 mol of carbon dioxide contains the same number of molecules as the number of atoms in 12g of carbon-12 The following equation represents a reaction. Cu(OH)2 (s) + 2HNO3 (aq)  Cu(NO3)2 (aq) + 2H2O (l) What are the reactants in this equation? a) Copper(II) nitrate and water b) Copper(II) nitrate and nitric acid c) Copper(II) hydroxide and nitric acid d) Copper(II) hydroxide and copper(II) nitrate

6.

Element M and element L are located in Group 1 and Group 16 in the Periodic Table respectively. Element M reacts with element L to form a compound. What is the chemical formula of the compound? a) ML b) ML2 c) M2L d) M2L3

7.

Element J and element Q have proton number of 12 and 9 respectively. What is the relative formula mass of a compound formed between J and Q? [Relative atomic mass : J = 24; Q = 19] a) 30 b) 43 c) 62 d) 67

8.

Table 1 show the pH values of four acidic solutions which have the same concentration. Solution pH value K 1.0 L 3.0 M 5.0 N 6.0 Table 1 Which acidic solution has the highest degree of dissociation? a) K b) L c) M d) N

9.

An oxide of element X has the empirical formula of X2O3. 2.24 g of element X reacts completely with 0.96 g of oxygen. What is the relative atomic mass of X? [Relative atomic mass : O = 16 ] a) 112 b) 56 c) 25 d) 17

10.

Which substance is an ionic compound? a) Ethanol, C2H5OH b) Sulphur dioxide, SO2 c) Tetrachloromethane, CCl4 d) Magnesium oxide, MgO

Which substances are electrolytes? I. Glucose II. Acetamide III. Lead(II)bromide IV. Sodium chloride a) b) c) d)

I and II I and III II and IV III and IV

11.

12.

Table 2 shows two elements and their respective relative atomic mass. The letters used are not the actual symbol of the elements. Element Relative atomic mass X 24 M 12 Table 2 Which of the following is true about the atoms of element X and M? a) The mass of 1 mol of X is twice the mass of 1 mol of M b) 1 mol of X has the same mass as 1 mol of M c) The mass of an atom of X is 24g and the mass of an atom of M is 12g d) The number of mole in 12g of atom X is equal to the number of mole in 12g of atom M The empirical formula of copper oxide is determined by its reaction with hydrogen. The heating, cooling or weighing steps are repeated several times but a constant mass of the product is still not obtained. Which of the following can be done to get a constant mass of the product? a) During heating, dry hydrogen gas is passed through b) During cooling, dry hydrogen gas is passed through c) During weighing, the combustion tube must be stoppered d) During heating, excess hydrogen gas is burnt

13.

Which of the following substances is acidic? a) Ammonia b) Potassium oxide c) Carbon dioxide d) Sodium hydroxide

14.

Which of the following is true about electrolytes? a) Elements that conduct electricity in molten state b) Compound that conduct electricity in solid state c) Elements that conduct electricity in solid or molten state d) Compounds that conduct electricity in molten state or aqueous solution

15.

Which statement explains why the size of the atoms of Group 1 elements increases when going down the group in the Periodic Table? a) The number of protons increases b) The relative atomic mass increases c) The number of valence electrons increases d) The number of shells with electrons increases

16.

The following equation shows the decomposition of hydrogen peroxide, H2O2. 2 H2O2 (l)  2H2O (l) + O2 (g) What is the volume of oxygen gas, O2 produced from the decomposition of 500 cm3 of 2 mol dm-3 hydrogen peroxide at standard temperature and pressure (STP)? [Molar volume of gas at STP = 22.4 dm3 mol-1] a) 11.2 dm3 b) 22.4 dm3 c) 33.6 dm3 d) 44.8 dm3

17.

Which element can form acidic oxides? I. Magnesium II. Sulphur III. Sodium IV. Phosphorus a) I and II b) I and III c) II and IV d) III and IV

18.

Metal X has the following properties.  Less reactive than iron  Does not react with iron(III)oxide Which metal oxide can react with X? a) Zinc oxide b) Magnesium oxide c) Copper(II)oxide d) Aluminium oxide

19.

Which substance is a covalent compound? a) Phosphorus(V)oxide b) Sodium sulphate c) Magnesium chloride d) Lead(II)chloride

20.

Which statement explains why the reactivity of Group 1 elements increases when going down the group? a) The physical state of the elements changes from gas to liquid then to solid at room temperature b) The attractive force between valence electron and the nucleus becomes stronger c) The valence electron gets further away from the nucleus d) The melting point of the elements decrease

21.

Table 3 shows the property of elements P, Q and R. These elements are located in the same period in the Periodic Table. Element Property of oxide P Acidic Q Basic R Amphoteric Table 3 Arrange the three elements based on the increasing of proton number. a) R, Q, P b) R, P, Q c) Q, P, R d) Q, R, P

22.

23.

Table 4 shows the electron arrangements of atoms P, Q, R and S. Atom Electron arrangement P 2.4 Q 2.8.1 R 2.8.2 S 2.8.7 Table 4 Which pair of atoms forms a compound by sharing electrons? a) P and S b) P and R c) Q and S d) Q and R Which of the following is a property of potassium fluoride? a) Volatile b) Insoluble in water c) Has a low melting point d) Conducts electricity in the molten state

24.

Table 5 shows information about three voltaic cells. Metals X, Y and Z are used as electrodes in the cells. Voltaic Negative Positive Voltage cell terminal terminal (V) I X Y 3.0 II Z Y 1.2 III X Z 1.8 Table 5 What is the order of the metals from the most electropositive to the least electropositive? a) X, Y, Z b) X, Z, Y c) Y, Z, X d) Z, X, Y

25.

Table 6 shows the positive terminal and voltmeter readings of three pairs of metals used as electrodes in voltaic cells. Pair of Positive Voltmeter metal terminal reading (V) R, S S 1.8 S, Q S 0.3 P, R R 0.2 Table 6 What is the voltmeter reading when P and Q are the pair of metals used as electrodes? a) 0.1V b) 0.5V c) 1.7V d) 2.3V

26.

Which electrolyte and electrodes can be used to purify copper? Electrolyte Electrode Anode Cathode a) Copper(II)sulphate Pure Impure solution copper copper b) Copper(II)nitrate Impure Pure solution copper copper c) Sulphuric acid Pure Impure copper copper d) Nitric acid Impure Pure copper copper

27.

Which of the following conatins 6.02 X 1023 atoms? a) 1 mol of nitrogen gas b) 1 mol of chlorine gas c) 1 mol of ammonia d) 1 mol of neon

28.

Which of the following is not a chemical property of acids? a) Reacts with carbonate to produce salt, water and carbon dioxide b) Reacts with reactive metal to produce salt and hydrogen c) Reacts with metal oxide to produce salt and water d) Reacts with alkali to produce salt and hydrogen

29.

0.1 mol dm-3 solution of X has a pH value of 13. Which statement is correct about the solution? a) X is a weak acid b) X is a strong alkali c) X dissociates partially in water d) X has a high concentration of hydrogen ions

30.

Table 7 shows the proton numbers of elements X and Y. X and Y are not the actual symbols of the elements. Element Proton number X 11 Y 19 Table 7 Which statements are true about elements X and Y? I. Atoms X and Y have one valence electron II. Element X is more reactive than element Y III. Atom X has a bigger atomic size than atom Y IV. Elements X and Y are in the same group in the Periodic Table a) b) c) d)

31.

I and III I and IV II and III II and IV

Alkali Y of concentration 1 mol dm-3 has a pH of 13. Which statement is true about alkali Y? a) Slightly soluble in water b) Reacts only with a weak acid c) The degree of ionization in water is high d) Has a low concentration of hydroxide ions

32.

Table 8 shows the electron arrangement for elements W, X, Y and Z. The letters used are not the actual symbol of the elements. Element Electron arrangement W 2.1 X 2.3 Y 2.8.3 Z 2.8.7 Table 8 Which of the following is an element of Period 3 and able to form an amphoteric oxide? a) W b) X c) Y d) Z

33.

Element T has the same chemical property as the element with the proton number of 20. The letter T is not the actual symbol of the element. Which of the following is the electron arrangement for an atom of element T? a) 2 b) 2.8.2 c) 2.8.4 d) 2.8.8

34.

What is the number of moles of copper (II) nitrate in 56.4g of copper (II) nitrate, Cu(NO3)2? [Relative atomic mass : O = 16, Cu = 64, N = 14] a) 0.30 mol b) 0.32 mol c) 0.45 mol d) 3.33 mol

35.

The following equation represents the neutralization reaction between barium hydroxide, Ba(OH)2 and hydrochloric acid, HCl. Ba(OH)2 + 2HCl  BaCl2 + 2H2O What is the volume of 0.5 mol dm-3 hydrochloric acid needed to neutralize 25 cm3 of 0.1 mol dm-3 barium hydroxide? a) 2.5 cm3 b) 5.0 cm3 c) 10.0 cm3 d) 12.5 cm3

36.

The chemical formula for potassium hexacyanoferrate (III) is K3Fe(CN)6. What is its relative formula mass? [Relative atomic mass of C = 12, N = 14, K = 39 and Fe = 56] a) 121 b) 199 c) 251 d) 329

37.

If the Avogadro number is represented by the letter x, what is the number of hydrogen gas particles, H2, with the molar volume of 24 dm3 mol-1 at room temperature and pressure? a) x b) 2x c) x2 d) 1/2x

38.

The mass of three atoms of element X is equal to the mass of four carbon atoms. X is not the actual symbol of the element. What is relative atomic mass of element X? [Relative atomic mass : C = 12] a) 48 b) 36 c) 16 d) 12

39.

A dibase acid, H2J has the concentration of 0.5 mol dm-3. Letter J is not the actual symbol of the element. What is the volume of potassium hydroxide, KOH, 1.0 mol dm-3 that can neutralize 25.0 cm3 of the H2J acid solution? a) 6.25 cm3 b) 12.50 cm3 c) 25.00 cm3 d) 50.00 cm3

40.

Sodium reacts with chlorine to form sodium chloride. 2Na + Cl2  2NaCl What is the mass of sodium chloride formed when 2.30g of sodium reacts with excess chlorine? [Relative atomic mass : Na = 23, Cl = 35.5] a) 2.93 g b) 3.85 g c) 9.40 g d) 11.70 g