A student reacts calcium carbonate with hydrochloric acid.
CaCO3(s) + 2HC(aq) →CaC2(aq) + H2O(l) + CO2(g)
What physical state does (g) represent in the balanced symbol equation?
Aqueous
Gas
Liquid
Solid
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Introducing Chemical Reactions
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Introducing Chemical Reactions
A student reacts calcium carbonate with hydrochloric acid.
CaCO3(s) + 2HC(aq) →CaC2(aq) + H2O(l) + CO2(g)
What physical state does (g) represent in the balanced symbol equation?
Aqueous
Gas
Liquid
Solid
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Look at the balanced symbol equation.
CaCO3 (s) + 2HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)
What does the symbol (s) represent in the balanced symbol equation?
Solid
Solute
Solution
Substance
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The symbol of an aluminium ion is Al3+.
The symbol of an oxide ion is O2−.
What is the formula of aluminium oxide?
AlO
Al2O
Al3O2
Al2O3
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The accurate relative atomic mass of aluminium is 26.9815385.
What is this number to 5 significant figures?
26.98153
26.981
26.98154
26.982
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Which results show that the pH of a solution is acidic?
pH = 3, Universal indicator colour = orange
pH = 10, Universal indicator colour = blue
pH = 3, Universal indicator colour = blue
pH = 10, Universal indicator colour = orange
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Why can the mass of a reaction in an open conical flask decrease?
One of the products is a gas.
One of the products is a solid.
One of the reactants is a liquid.
One of the reactants is a solid.
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63.5g of copper reacts to make 134.5g of copper chloride, CuCl2
Cu + Cl2 → CuCl2
How much copper chloride will be made from 0.635g of copper?
0.001345 g
0.1345 g
1.345 g
13.45 g
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Calcium carbonate, CaCO3, thermally decomposes to make calcium oxide, CaO, and carbon dioxide.
CaCO3 → CaO + CO2
5.0 g of calcium carbonate makes 2.8 g of calcium oxide.
How much carbon dioxide is made?
2.2 g
2.8 g
4.4 g
7.8 g
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The formula of an iron(III) ion is Fe3+ and the formula of the sulfate ion is SO42-.
What is the formula of iron(III) sulfate?
Fe2SO4
Fe3(SO4)2
Fe2(SO4)3
(Fe)2(SO4)3
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Avogadro's constant has a value of 6.02 x 1023.
How many hydrogen atoms are in 0.05 moles of hydrogen molecules?
3.01 x 1022
3.01 x 1023
6.02 x 1022
6.02 x 1024
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Which equation shows the formation of a Group 5 non-metal ion?
X represents a Group 5 non-metal and e- represents an electron.
X + e- → X-
X + 3e- → X3-
X → X3-+ 3e-
X + 5e- → X5-
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A piece of iron wool is left in moist air and goes rusty.
Which graph shows how the mass of the iron wool changes?
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A student wanted to make 15.0 g of zinc chloride. The equation for the reaction is:
ZnCO3 + 2HCl → ZnCl2 + CO2 + H2O
What mass of zinc carbonate should the student add to the hydrochloric acid to make 15.0 g of zinc chloride?
Relative atomic masses (Ar): C = 12 Zn = 65 O= 16 Cl = 35.5 H= 1
11.0 g
13.8 g
15.0 g
22.0 g
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Symbol equations always need to have the same number of atoms on both sides.
Which equation is correctly balanced?
H2SO4 + 2NaOH → Na2SO4 + H2O
Ca(OH)2 + 2HCl → CaCl2 + H2O
4Na + O2 → 2Na2O
2Cu + 8HNO3 → 2Cu(NO3)2 + 2NO + 4H2
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How many moles are present in 9 kg of glucose, C6H12O6?
Relative formula mass (Mr): C6H12O6 = 180
0.02 mol
0.05 mol
20 mol
50 mol
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What is the mass of 0.25 moles of hydrated copper(II) sulfate, CuSO4.5H2O?
Relative formula mass (Mr): H2O = 18 CuSO4 = 160
40.0 g
44.5 g
62.5g
1000 g
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2.7 g aluminium reacts with 38.1 g of iodine, I2, to make 40.8 g aluminium iodide, AlI3.
Relative atomic masses (Ar): Al = 27 I = 127
Relative formula mass (Mr): AlI3 = 408
What coefficients would balance the equation for the reaction?
1 : 3 : 2
2 : 1 : 2
2 : 3 : 2
3 : 2 : 3
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Nitrogen and hydrogen react together to make ammonia.
N2 + 3H2 → 2NH3
If 2.0 g of hydrogen is added to 12.0 g of nitrogen which substance is the limiting reactant and how much of the excess reactant remains?
Relative atomic masses (Ar): H = 1 N = 14
| Limiting Reactant | Mass of excess reactant |
A | nitrogen | 2.0 g |
B | nitrogen | 10.0 g |
C | hydrogen | 2.7 g |
D | hydrogen | 9.3 g |
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When 12 g of carbon (C) burns in oxygen (O2), 44 g of carbon dioxide (CO2) is formed.
What mass of C would burn to form 11 g of CO2?
3 g
4 g
11 g
12 g
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Lead nitrate contains lead ions, Pb2+, and nitrate ions, NO3-.
What is the formula for lead nitrate?
PbNO3
Pb(NO3)2
Pb2NO3
Pb2(NO3)2
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Hydrogen gas can be made by reacting methane and steam (H2O).
CH4 + H2O 3H2 + CO
6 g of hydrogen gas can be made from 18 g of steam, H2O.
How much hydrogen gas can be made from 3.6 g of steam, H2O?
0.4 g
0.6 g
1.2 g
6.8 g
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Ethanol, C2H5OH, burns in oxygen. Carbon dioxide and water are made.
Which equation for this reaction is correctly balanced?
C2H5OH + O2 → CO2 + H2O
C2H5OH + 3O2 → 2CO2 + 3H2O
C2H5OH + 2O2 → 3CO2 + 2H2O
2C2H5OH + 7O2 → 4CO2 + 6H2O
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Oxygen reacts with 1.20 g of carbon. 4.40 g of carbon dioxide forms.
C + O2 → CO2
What mass of oxygen is used in this reaction?
0.80 g
1.60 g
3.20 g
5.60 g
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The formula of a magnesium ion is Mg2+.
The formula of a nitrate ion is NO3-.
What is the formula of magnesium nitrate?
MgNO3
Mg2NO3
Mg(NO3)2
Mg2(NO3)3
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Urea, (NH2)2CO, is a fertiliser.
A student makes 1 mole of urea from 2 moles of ammonia.
What is the mass of urea that the student makes?
43.0 g
44.0 g
58.0 g
60.0 g
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Magnesium reacts with chlorine. Magnesium chloride is made.
What is the balanced symbol equation for this reaction?
Mg + Cl → MgCl
Mg + Cl2 → MgCl2
2Mg + Cl2 → 2MgCl
2Mg + Cl2 → Mg2Cl2
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Which of these shows the balanced symbol equation for the reaction between potassium and chlorine to make potassium chloride?
K + Cl2 ➞ KCl2
P + Cl2 ➞ PCl2
2K + Cl2 ➞ 2KCl
2P + Cl2 ➞ 2PCl
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Magnesium is heated in a crucible.
The mass of the crucible and magnesium increases.
Which statement is the best explanation for this?
Oxygen is given off.
The magnesium melts.
The magnesium is oxidised to magnesium oxide.
The magnesium reacts to make magnesium carbonate.
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A student neutralises nitric acid with potassium hydroxide solution.
Which equation shows the ionic equation for neutralisation?
HNO3 + KOH → KNO3 + H2O
H+ + OH– → H2O
NO3 – + K+ → KNO3
H+ + NO3 – → HNO3
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What is the amount, in mol, of 15 g of carbonate ions, CO32-?
0.18
0.25
4.0
5.6
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Look at the diagram.
It shows how the reaction between hydrochloric acid and marble chips (calcium carbonate) can be monitored.
The reading on the balance decreases during the reaction.
Which statement is the best explanation?
Acid escapes from the flask.
Carbon dioxide gas is made which leaves the flask.
Hydrogen gas is made which leaves the flask.
The temperature in the laboratory changes.
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How many moles are in 30 g of nitrogen, N2?
Relative atomic mass (Ar): N = 14.0
0.47mol
0.93mol
1.07mol
2.14mol
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Hydrochloric acid, HCl, reacts with magnesium, Mg.
Magnesium chloride and hydrogen are made.
What is the balanced symbol equation for this reaction?
2HCl + Mg → MgCl + H2
2HCl + Mg → MgCl + H
2HCl + Mg → MgCl2 + H2
2HCl + Mg → MgCl2 + H
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Avogadro’s constant has a value of 6.02 × 1023.
How many oxygen atoms are in 0.25 moles of oxygen molecules?
1.204 × 1024
1.505 × 1023
3.010 × 1023
6.020 × 1023
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Avogadro’s constant has a value of 6.02 × 1023.
What is the number of atoms in 0.5 mol of water?
2.00 × 1023
3.01 × 1023
6.02 × 1023
9.03 × 1023
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Methane burns in oxygen to form carbon dioxide and water.
CH4 + 2O2 → CO2 + 2H2O
Calculate the amount of carbon dioxide made when 6.4 g of methane is burnt.
2.8 g
4.4 g
14.4 g
17.6 g
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Sodium hydroxide reacts with hydrochloric acid. Sodium chloride and water are made.
NaOH + HCl → NaCl + H2O
What mass of sodium hydroxide would be needed to make 46.8 g of sodium chloride?
16 g
32 g
50 g
64 g
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Phosphoric acid contains phosphate ions,
Phosphoric acid is completely neutralised by sodium hydroxide.
What is the formula of the salt that is made?
Na2PO4
Na3PO4
Na(PO4)3
Na2(PO4)3
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Calcium phosphate contains the ions Ca2+ and PO43–.
What is the formula for calcium phosphate?
CaPO4
Ca2PO4
Ca2(PO4)3
Ca3(PO4)2
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